Method for manufacturing laminated sheet and device for manufacturing laminated sheet

Abstract

A method for manufacturing a laminated sheet including a synthetic resin sheet and a cushion material laminated in this order in the direction from the front side to the back side and having protrusions and recesses at least on the front side thereof, the method comprising: a preparation step for producing a laminated sheet material by adhering the cushion material to the back side of the synthetic resin sheet; a softening step for softening the laminated sheet material by heating the same; and a shaping step for providing protrusions and recesses by performing vacuum suction from the front side of the laminated sheet through a shaping die formed from a porous member, the average pore diameter of the shaping die being 10-40 μm.

Description

Laminated sheet manufacturing method and laminated sheet manufacturing device

[0001] The present invention relates to a method and an apparatus for manufacturing a laminated sheet.

[0002] Conventionally, a method for manufacturing a laminated sheet is known in which a laminated sheet material having a cushioning material made of synthetic resin foam attached to the back surface of the outer material is subjected to a heat press process to create an uneven shape on the surface of the laminated sheet material (see, for example, Patent Documents 1 and 2).

[0003] Furthermore, a method for manufacturing a laminated sheet having a textured surface employs a vacuum suction machine (see, for example, Patent Documents 3 and 4). In particular, Patent Document 4 describes the use of a ceramic permeable patterned cylinder (a molding die made of porous ceramic).

[0004] Japanese Patent Publication No. 2003-326598 Japanese Patent Publication No. 2019-142231 Chinese Patent Application Publication No. 106192432 Chinese Patent Application Publication No. 103114408

[0005] In the manufacturing methods of laminated sheets as described in Patent Documents 1 and 2, the uneven shape is formed by heat pressing or the like, so depending on the uneven shape to be obtained, the surface of the laminated sheet material may not be able to conform to the surface of the mold, making it difficult to obtain a shape that faithfully corresponds to the mold. For example, the contour of the uneven shape may be drooped (gentler) compared to the desired contour that corresponds to the mold, making it impossible to obtain the desired uneven shape.

[0006] In recent years, there has been a demand for more complex patterns of protrusions and recesses on the surface of laminated sheets, such as a pattern that mimics quilting (also called a quilting pattern). A quilting pattern, for example, includes a mixture of relatively large protrusions and recesses (valleys) between the protrusions, and fine protrusions and recesses that mimic sewing threads and are formed in the grooves of the relatively large protrusions and recesses. These relatively large protrusions and recesses and fine protrusions are sometimes collectively referred to as a protrusion or recess.

[0007] The vacuum embossing method using vacuum suction, as described in Patent Documents 3 and 4, is suitable for forming minute irregularities on the very surface of an outer fabric. Therefore, it is possible to effectively reproduce, for example, minute irregularities such as the wrinkles known as grain found on the surface of genuine leather, as well as minute irregularities (shapes resembling sewing threads) that constitute part of the quilting pattern. However, it has often been difficult to form (i) the entire quilting pattern (a pattern including both minute irregularities resembling sewing threads and relatively large irregularities) or (ii) a pattern including both grain and large irregularities as desired using only vacuum embossing. For example, even if an outer fabric (synthetic resin sheet) is processed using vacuum embossing to form an irregularity and then a cushioning material is attached to the back side, the cushioning material may not be able to conform to the irregularities of the outer fabric, resulting in unintended depressions (flattening) in raised areas that should be plump (see FIG. 16).

[0008] In view of the above, one aspect of the present invention aims to provide a method for manufacturing a laminated sheet that can faithfully impart a desired shape even to a complex uneven shape that includes not only fine unevenness but also relatively large unevenness.

[0009] One aspect of the present invention is a method for manufacturing a laminated sheet that includes a synthetic resin sheet and a cushioning material laminated in this order from front to back, and that has irregularities on at least the front side, the method including: a preparation step of attaching the cushioning material to the back side of the synthetic resin sheet to produce a laminated sheet material; a softening step of heating and softening the laminated sheet material; and an irregularity imparting step of imparting irregularities to the front side of the laminated sheet material by vacuum suction through a porous ceramic forming mold, wherein the porosity of the forming mold is 20% or more and 60% or less.

[0010] According to one aspect of the present invention, it is possible to provide a method for producing a laminated sheet that can faithfully impart a desired shape even if the shape is complex and uneven.

[0011] 1 is a photograph taken from the front side of an example of a laminate sheet manufactured according to one embodiment of the present invention. It is a schematic diagram of an enlarged top view of portion III of FIG. 1. It is a schematic diagram of a cross section taken along line I-I of FIG. 1. It is a schematic diagram of a cross section taken along line II-II of FIG. 1. It is a cross section corresponding to FIG. 3 of a modified laminate sheet. It is a cross section corresponding to FIG. 3 of an example in which the height of the raised portions is relatively large. It is an explanatory diagram showing a preparation step in a manufacturing method of a laminate sheet according to one embodiment. It is a cross section showing a laminate sheet material produced in the preparation step in one embodiment. It is an explanatory diagram showing a softening step, a forming step, and a hardening step in a manufacturing method of a laminate sheet according to one embodiment. It is a cross section showing a schematic of a vacuum suction roll machine used in the forming step. It is an explanatory diagram of the manufacturing of a mold used in the vacuum suction roll machine. It is a cross section showing a schematic of a cooling roller used in the hardening step. It is an explanatory diagram showing a manufacturing method according to a first conventional technology. It is an explanatory diagram showing a manufacturing method according to a second conventional technology. It is a graph obtained in the measurement of pore size in Example 1. It is a photograph of a laminate sheet manufactured by a manufacturing method according to a conventional technology in which unintended depressions have occurred.

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, unless otherwise specified, the same or corresponding components will be denoted by the same reference numerals and their description may be omitted. In addition, in this specification, the side exposed when the laminate sheet is in use will be referred to as the "front side," the front surface of each component will be referred to as the "surface," the side not exposed when the laminate sheet is in use will be referred to as the "rear side," and the back surface of each component will be referred to as the "rear surface."

[0013] <Laminate Sheet> First, the laminate sheet manufactured according to this embodiment will be described. The laminate sheet 10 is suitable for use as a skin material for interior parts (seats, instrument panels, door trim, ceilings, etc.) of automobiles, railway vehicles, aircraft, etc. Fig. 1 shows a photograph of an example of the laminate sheet 10 taken from the front side. Fig. 2 shows a schematic drawing of an enlarged top view of a portion III in Fig. 1. Fig. 3 shows a schematic cross-section along line I-I in Fig. 2, and Fig. 4 shows a schematic cross-section along line II-II in Fig. 1.

[0014] As shown in Figures 1 to 4, the laminated sheet 10 according to this embodiment includes a synthetic resin sheet 20 and a cushion material 30 laminated in this order from front to back, and is a sheet having irregularities at least on the front side. More specifically, as shown in Figures 3 and 4, the laminated sheet 10 is formed of a laminated sheet material 11 in which a sheet-like cushion material 30 is attached to the back side of the synthetic resin sheet 20. The overall thickness of the synthetic resin sheet 20 in the laminated sheet material 11 may be 1 mm or more and 5 mm or less, and the overall thickness of the cushion material 30 may be 5 mm or more and 15 mm or less.

[0015] 3 and 4, the synthetic resin sheet 20 may be a sheet including a base fabric layer 21, a surface skin layer 24, and a surface treatment layer 25 laminated in this order from the back side to the front side. The synthetic resin sheet 20 used in this embodiment may preferably be synthetic leather. In this specification, "synthetic leather" refers to an artificial material in which a synthetic resin is applied to the surface of a fabric to give it a texture similar to that of natural leather.

[0016] The base fabric layer 21 may be composed of a fabric (fiber aggregate) made of fibers in the form of a nonwoven fabric, a woven fabric, a knitted fabric, or the like. Among these, woven fabric or knitted fabric is preferred because of its low cost and availability. Alternatively, the base fabric layer 21 may be a sheet material having a porous structure obtained by impregnating a fabric with a synthetic resin such as a polyurethane resin. The base fabric layer 21 functions to support and reinforce the layers formed on its front side. The presence of the base fabric layer 21 can enhance the strength and shape stability of the synthetic resin sheet 20. The base fabric layer 21 may be bonded to the back surface of the skin layer 24 with an adhesive. That is, in the laminated sheet material 11, an adhesive layer may be formed between the base fabric layer 21 and the skin layer 24.

[0017] In this embodiment, the synthetic resin sheet 20 does not necessarily have to have the base fabric layer 21. For example, as in the modified example shown in Fig. 5, the synthetic resin sheet 20 may be made of a surface layer 24 and a surface treatment layer 25, with the cushioning material 30 attached to the back side of the surface layer 24. In a configuration without the base fabric layer 21, the laminate sheet 10 can achieve high deformability, and is therefore preferable for applications requiring large flexible deformation.

[0018] The skin layer 24 may be a layer containing a synthetic resin. Examples of synthetic resins contained in the skin layer 24 include polyvinyl chloride (PVC) resin and polyurethane (PU) resin. Of these, polyvinyl chloride (PVC) resin is preferred because of its durability and ease of decorative processing. The skin layer 24 may contain additives such as plasticizers, stabilizers, and fillers as needed. The thickness of the skin layer 24 can be selected appropriately depending on the purpose, but is preferably 100 μm to 1000 μm, more preferably 200 μm to 800 μm, and even more preferably 250 μm to 450 μm.

[0019] The surface treatment layer 25 is a layer containing a synthetic resin different from the resin constituting the skin layer 24 and can be formed by applying a synthetic resin-containing liquid. The thickness of the surface treatment layer 25 can be selected appropriately depending on the purpose, but is preferably 5 μm to 20 μm, more preferably 10 μm to 20 μm. The thickness of the surface treatment layer 25 may be thinner than the thickness of the skin layer 24. Forming the surface treatment layer 25 can impart a unique texture and feel to the surface of the synthetic resin sheet 20, particularly when the synthetic resin sheet 20 is made of synthetic leather, resulting in a texture (gloss, etc.) and feel similar to that of natural leather. The synthetic resin is preferably an aqueous polyurethane (PU) resin, and examples of polyurethane resins include polycarbonate polyurethane, polyester polyurethane, and polyether polyurethane. The synthetic resin-containing liquid used to form the surface treatment layer 25 is formulated according to the texture, feel, surface friction characteristics, etc. desired for the synthetic resin sheet 20. The surface treatment layer 25 may contain additives such as a crosslinking agent or a lubricant, as needed.

[0020] The surface treatment layer 25 may be composed of a single layer as shown in Fig. 3 or may be composed of multiple layers, for example, two layers. When the surface treatment layer 25 is composed of multiple layers, the materials constituting the multiple layers may be the same or different. The surface treatment layer 25 may also contain a colorant.

[0021] Furthermore, an intermediate layer may be provided between the base fabric layer 21 and the surface layer 24. The intermediate layer may be adhered to the front side of the base fabric layer 21 via an adhesive layer. The intermediate layer may be composed of a foamed or non-foamed material, such as a synthetic resin foam containing polyvinyl chloride. The intermediate layer may contain additives such as plasticizers, stabilizers, fillers, foaming agents, and flame retardants, as needed. The material and thickness of the intermediate layer may be appropriately determined taking into account the texture and intended use of the synthetic resin sheet 20.

[0022] 3 and 4, the cushioning material 30 may include a sheet-like synthetic resin foam 31 and a backing fabric layer 32 disposed on the back side of the synthetic resin foam 31. Alternatively, the cushioning material 30 may be made of the synthetic resin foam 31 without including the backing fabric layer 32.

[0023] The material for the synthetic resin foam 31 is not particularly limited, but may be a foamed plastic, preferably a foamed plastic containing polyurethane. More specifically, the synthetic resin foam 31 may be a so-called soft urethane foam or a stripped urethane foam, which has interconnected cells and is relatively soft and resilient. The synthetic resin foam 31 is formed by mixing polyurethane as the base material with additives such as a catalyst and a blowing agent, and then subjecting the mixture to a foaming reaction and a resinification reaction. The hardness of the polyurethane-containing synthetic resin foam 31 can be easily adjusted by changing the manufacturing conditions. Therefore, the hardness of the cushioning material 30 can be appropriately adjusted depending on the material and hardness of the synthetic resin sheet 20, the application and specifications of the laminate sheet 10, and other requirements, thereby enabling the laminate sheet material 11 to be configured so that the uneven surface 11a can be easily formed.

[0024] The density of the synthetic resin foam 31 is 0.020 g / cm ３ 0.050g / cm or more ３ It is preferable that the thickness of the synthetic resin foam 31 is 5.0 mm or more, preferably 5.0 mm or more and 20.0 mm or less, more preferably 2 mm or more and 10 mm or less, and even more preferably 3 mm or more and 8 mm or less. When the thickness of the synthetic resin foam 31 is 5.0 mm or more, the laminate sheet 10 can obtain a clear uneven shape 12 (described in more detail later). The synthetic resin foam 31 according to this embodiment has, for example, a density of 0.030 g / cm ３ A foamed polyurethane sheet having a thickness of 5.0 mm is used. The "density" is a value at 4°C.

[0025] The backing fabric layer 32 may be made of the same material as the above-described backing fabric layer 21. That is, it may be made of a fabric (fiber assembly) in the form of a nonwoven fabric, a woven fabric, a knitted fabric, or the like. The backing fabric layer 32 can increase the strength and shape stability of the cushioning material 30 and, ultimately, the laminated sheet 10. The thickness of the backing fabric layer 32 is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 300 μm to 1,300 μm, more preferably 400 μm to 700 μm.

[0026] The method for manufacturing a laminate sheet according to this embodiment forms irregularities on the front side of the laminate sheet material 11, thereby obtaining a laminate sheet 10 with a predetermined irregular shape (irregular pattern) 12. The irregular shape formed on the laminate sheet 10 is not particularly limited, but may be a pattern in which, when viewed in at least one direction perpendicular to the thickness direction, a plurality of protrusions 12a are formed and at least one recess 12b is formed between the protrusions 12a. Furthermore, the irregular shape 12 is preferably one in which, when viewed in any direction perpendicular to the thickness direction, the width of the recess 12b is smaller than the width of the protrusion 12a.

[0027] In the example shown in Figures 1 to 4, the uneven shape 12 has a pattern (quilting pattern) that imitates quilting. Quilting is generally a process of stitching (stabbing) a laminate formed by sandwiching a cushioning layer between two sheets. Therefore, on the surface of a quilted article, groove-like depressions are formed by linear portions sewn with thread (stitch lines or stitch patterns), and the portions between the stitch lines are raised, thereby forming an uneven shape. The quilting pattern in the laminate sheet 10 may be an uneven pattern that imitates the uneven shape obtained by the quilting process, or in other words, an uneven pattern in which the uneven shape obtained by the quilting process is reproduced in the laminate sheet material 11 without sewing.

[0028] In the example shown in FIGS. 1 to 4 , the uneven shape 12 includes a relatively large uneven shape (hereinafter also referred to as a large uneven shape) G12. This large uneven shape G12 has a shape in which a plurality of relatively large raised portions G12a that rise to the front side are arranged in the surface direction, and grooves (valley portions) G12b are formed between the raised portions G12a. The grooves G12b can be considered to be depressions that extend linearly in a planar view. Furthermore, finer unevenness (hereinafter also referred to as a fine uneven shape) M12 is formed at the bottom of the grooves G12b of the large uneven shape G12. As shown in FIGS. 2 and 4 , the fine uneven shape M12 has a shape in which raised portions M12a and recessed portions M12b are alternately arranged along the extension direction of the elongated grooves G12b. When the uneven shape formed on the laminate sheet 10 is a quilting pattern, the grooves G12b are portions that mimic the depressions formed by stab stitching in a quilted product, and the fine uneven shape M12 is a portion that mimics the stitch pattern formed by stab stitching (the protrusions M12a are portions that mimic the areas where the thread is exposed on the surface, and the depressions M12b are portions that mimic the areas where the thread is inserted inside). In the laminate sheet 10 obtained by the manufacturing method of this embodiment, the uneven shape 12 formed on the front side of the laminate sheet 10 includes the large uneven shape G12 and the fine uneven shape M12 of different sizes as described above. According to this embodiment, even such a somewhat complex uneven shape can be formed in one process.

[0029] In addition, the raised portion G12a in the large uneven shape G12 and the convex portion M12a in the fine uneven shape M12 may be collectively referred to simply as the convex portion 12a, and the groove G12b in the large uneven shape G12 and the concave portion M12b in the fine uneven shape M12 may be collectively referred to simply as the concave portion 12b.

[0030] In plan view, the width W ( FIG. 2 ) of the groove G12b in the large uneven shape G12 may be preferably 0.5 mm or more and 3 mm or less, more preferably 1.5 mm or more and 2 mm or less. Furthermore, the groove G12b may be linear or curved in plan view, or may be bent or curved. Furthermore, since the raised portion G12a is an area surrounded or sandwiched by one or more grooves G12b, it may have various shapes depending on the shape of the grooves G12b. For example, the plan view shape of one raised portion G12a (or the plan view shape with the groove G12b as the outer contour) may be approximately square as shown in FIG. 1 , or may be a quadrangle other than a square, a polygon other than a quadrangle, a circle, an ellipse, or the like. Furthermore, multiple raised portions G12a may have the same plan view shape or different plan view shapes from each other.

[0031] The height h1 of the raised portion G12a (FIG. 3) may be 1 mm or more and 20 mm or less, more preferably 1 mm or more and 10 mm or less, even more preferably 2 mm or more and 15 mm or less, and even more preferably 3 mm or more and 8 mm or less. When the fine uneven shape M12 is formed in the groove G12b, the height h1 of the raised portion G12a may be the height from the surface of the recess M12b of the fine uneven shape M12 to the top surface of the raised portion G12a.

[0032] Furthermore, if the height h1 of the raised portion G12a is relatively large relative to the thickness of the synthetic resin foam 31, for example, if it is equal to or larger than the thickness of the synthetic resin foam 31, then unevenness may also be formed on the back side of the laminate sheet 10 in accordance with the rise of the raised portion G12a on the front side of the laminate sheet 10. That is, as shown in FIG. 6 , the backing fabric layer 32 may deform so as to be recessed from the back side to the front side at a position corresponding to the raised portion G12a. Even if unevenness is formed on the back side of the laminate sheet 10, the cushioning material 30 is sufficiently thick, so that the elasticity of the laminate sheet 10 is not affected. Furthermore, when unevenness is formed on the back side of the laminate sheet 10, large raised portions that cannot be obtained by other press molding methods can be formed, and the shape of such raised portions is highly stable over time.

[0033] The fine uneven shape M12 may be formed on the bottom of the groove G12b. When the uneven shape 12 is a quilting pattern, the fine uneven shape M12 has a pattern that looks like a sewing thread (a pattern that reproduces the stitches of the thread). The convex portions M12a correspond to the portions where the sewing thread is exposed on the surface. The surface of the convex portions M12a may further have unevenness that imitates the twist of the sewing thread, as shown in FIG. 2, for example. Note that the twist pattern of the sewing thread reproduced in the fine uneven shape M12 illustrated in FIG. 2 is a pattern formed by twisting two threads, but the unevenness that imitates the twist of the sewing thread may also reproduce a pattern formed by twisting three or more threads. Note that the twist pattern of the thread is omitted in FIG. 4.

[0034] When the fine concave-convex shape M12 is a pattern that reproduces a sewing thread, the width w of the convex portions M12a included in the fine concave-convex shape M12 may be equal to or smaller than the width W of the grooves G12b. The width w of the convex portions M12a (FIG. 2) may be 0.4 mm or more and 1.2 mm or less, preferably 0.4 mm or more and 1 mm or less. The height h2 of the convex portions M12a (FIG. 3) may also be 0.4 mm or more and 1.2 mm or less, preferably 0.4 mm or more and 1 mm or less. The height h2 of the convex portions M12a can also be said to be a dimension corresponding to the thickness of the reproduced sewing thread. The thickness of the sewing thread refers to the maximum thickness of the sewing thread in the case of a twisted sewing thread.

[0035] In addition, when the synthetic resin sheet 20 is synthetic leather, the surface of the skin layer 24 may also be formed with a background pattern that imitates the irregular wrinkles (grain) on the surface of natural leather. The background pattern is also an unevenness formed on the surface of the synthetic resin sheet 20 and is included in the fine unevenness M12 in this specification. For example, the height difference of the unevenness of the background pattern that imitates grain is approximately 30 μm or more and 1 mm or less, which is smaller than the height difference of the unevenness of the large unevenness shape G12 described above (height h1 of the raised portion G12a). Furthermore, it is smaller than the height difference of the unevenness of the fine unevenness shape M12, which is a pattern that reproduces the stitches of a sewing thread (height h2 of the raised portion M12a).

[0036] <Method for manufacturing laminated sheet> The method for manufacturing a laminated sheet according to this embodiment includes a preparation step (S10) of attaching the cushioning material to the back side of a synthetic resin sheet to prepare a laminated sheet material, a softening step (S20) of heating and softening the laminated sheet material, and a molding step (S30) of applying a vacuum to the front side of the laminated sheet material through a porous ceramic mold to create an uneven surface. Furthermore, a curing step (S40) may optionally be included after the molding step (S30). Each step will be described below.

[0037] (S10: Preparation Step (See FIG. 7)) In the preparation step (also referred to as the bonding step or the laminated sheet material fabrication step), first, a synthetic resin sheet 20 made of a predetermined material and a sheet-like cushion material 30 are prepared. The synthetic resin sheet 20 and the cushion material 30 may each have a long strip shape of a predetermined width and be wound into a roll. Then, the synthetic resin sheet 20 and the cushion material 30 are set in, for example, a commercially available frame laminator 100 (FIG. 7) equipped with a burner 101.

[0038] Next, using a frame laminating machine 100, the front surface 31a of the synthetic resin foam 31 of the cushion material 30 is attached to the back surface 21b of the base fabric layer 21 of the synthetic resin sheet 20 by frame lamination. This allows for the production of a laminated sheet material 11 in which the synthetic resin sheet 20 and the cushion material 30 are integrated, as shown in Figure 8. As shown in Figure 8, the front surface 11a of the laminated sheet material 11 becomes the front surface of the synthetic resin sheet 20 (the front surface of the surface treatment layer 25), and the back surface 11b of the laminated sheet material 11 becomes the back surface of the cushion material 30 (the back surface of the back base fabric layer 32). The front surface 11a of the laminated sheet material 11 is flat.

[0039] The frame lamination process is a process in which the surface 31a of the synthetic resin foam 31 of the cushioning material 30 is heated and melted by a burner 101 or the like, and then bonded to the synthetic resin sheet 20, which is another base material.

[0040] In the frame lamination process, the depth of the melted portion on the front side of the synthetic resin foam 31 from the outermost surface may be 2 mm or less. The entire area of ​​the surface 31a of the synthetic resin foam 31 where the synthetic resin sheet 20 is attached (also referred to as the synthetic resin sheet attachment area) is melted in a plan view. This enhances the integrity of the synthetic resin sheet 20 and the cushioning material 30, improving the quality of the resulting laminated sheet 10 (reproducibility of complex uneven shapes, flexibility). However, as long as the uneven shape of the original product or molding die, particularly the raised portions, can be sufficiently reproduced, the synthetic resin sheet attachment area does not necessarily have to be melted entirely.

[0041] The method for bonding the synthetic resin sheet 20 and the cushioning material 30 in the preparation step is not limited to the frame lamination process described above; an adhesive method may also be used. Examples of adhesive methods include applying a fluid adhesive to at least one of the back surface of the synthetic resin sheet 20 and the front surface of the cushioning material 30, and then bonding the two together; and placing a sheet-like adhesive, such as a hot-melt sheet, between the synthetic resin sheet 20 and the cushioning material 30 and then heating the sheet-like adhesive to soften or melt it. When bonding the synthetic resin sheet 20 and the cushioning material 30 using a separate adhesive, selecting the appropriate adhesive can ensure strong adhesion between the synthetic resin sheet 20 and the cushioning material 30, resulting in a highly durable laminated sheet. On the other hand, the frame lamination process described above is preferable because it does not require the use of a dissimilar adhesive and prevents the adhesive layer from hardening, which would impair the flexibility of the laminated sheet material 11.

[0042] Alternatively, a polyurethane elastomer containing a foaming agent may be heated and kneaded, and the resulting resin composition may be formed into a sheet by a calendaring method to obtain an unfoamed resin sheet, which may then be attached to a synthetic resin sheet 20 in a heated state, and the foaming agent may be foamed at a high temperature of about 200° C., thereby producing a laminated sheet material 11 in which the synthetic resin sheet 20 and the cushion material 30 are integrated. Thus, the term "cushion material" in this specification may include not only cushion materials that themselves have high cushioning properties, but also cushion material precursors that foam when treated by heating or the like, such as the unfoamed resin sheet.

[0043] As yet another method, the adhesive surface of the synthetic resin foam 31 of the cushioning material 30 and / or the adhesive surface of the base fabric layer 21 of the synthetic resin sheet 20 can be softened by plasma treatment or the like, and then the two can be bonded together.

[0044] (S20: Softening Step (See FIG. 9)) In the softening step, the laminate sheet material 11 obtained in the preparation step is softened to facilitate the formation of irregularities in the subsequent molding step. For example, if the laminate sheet material 11 is obtained in the preparation step in a rolled state, the laminate sheet material 11 is pulled out (unwound) and passed through a heater 102 set to a predetermined temperature. As a result, the laminate sheet material 11 is heated from the surface 11a side, and at least the skin layer 24 and the surface treatment layer 25 of the synthetic resin sheet 20 are softened. In other words, the heater 102 softens at least the surface 11a of the laminate sheet material 11, including the skin layer 24. Then, the laminate sheet material 11 with its surface 11a softened is continuously sent to the next step without being wound up.

[0045] Here, the heater 102 includes a housing 102a that is long along the conveyance direction of the laminated sheet material 11 and multiple heaters 102b (four heaters in the embodiment shown in FIG. 9 ) installed within the housing 102a. The housing 102a is, for example, 12 m long, and the heating length of the laminated sheet material 11 can be set depending on the length of the housing 102a. The multiple heaters 102b are each attached to the upper part of the housing 102a (e.g., the top surface of the housing 102a) along the conveyance direction of the laminated sheet material 11, thereby heating the surface 11a of the laminated sheet material 11. Note that the heaters 102b may also be attached to the lower part of the housing 102a (e.g., the bottom surface of the housing 102a, or the back side of the laminated sheet material 11) as long as they can heat the surface 11a of the laminated sheet material 11. Furthermore, the heaters 102b, 102b, . . . may be attached to both the upper and lower parts of the housing 102a, and may heat the front and back sides of the laminated sheet material 11 simultaneously.

[0046] Furthermore, the temperature of each heater 102b can be set individually, and the set temperature can be set to gradually increase from the sheet inlet 102c side of the housing 102a toward the sheet outlet 102d side. That is, in the softening process of this embodiment, the temperature to which the laminated sheet material 11 is heated can be set to gradually increase along the conveyance direction of the laminated sheet material 11. For example, the heating temperature can be set to increase in stages or gradually. The set temperatures of each heater 102b, 102b, ... are set arbitrarily depending on the softening state of the surface layer 24 of the laminated sheet material 11. In one embodiment, the set temperatures can be set to 120°C, 140°C, 150°C, and 180°C from the sheet inlet 102c side toward the sheet outlet 102d, respectively. Furthermore, a heat-retaining heater 102e is installed between the sheet outlet 102d and the vacuum suction roll machine 103 used in the subsequent molding process. The heater 102e for heat retention heats the surface 11a of the laminated sheet material 11 after the laminated sheet material 11 is discharged from the sheet discharge port 102d of the heater 102, and prevents a decrease in temperature of the surface 11a of the laminated sheet material 11 until it is formed. The heaters 102b, 102b, ... of the heater 102 are used in a temperature range of 120°C to 200°C. The softened laminated sheet material 11 is transported to the subsequent vacuum suction roll machine 103.

[0047] (S30: Molding Step (See FIGS. 9 and 10)) In the molding step (also referred to as the texture-imparting step), as shown in FIG. 9 , the laminated sheet material 11, whose surface 11 a including the skin layer 24 has been softened in the softening step, is placed with the surface 11 a facing a vacuum suction roll machine 103, and in this state, the front side of the laminated sheet material 11 is vacuum-suctioned by the vacuum suction roll machine 103. That is, the vacuum suction roll machine 103 vacuum-suctions the surface 11 a of the laminated sheet material 11 including the skin layer 24 through an air-permeable forming mold 105. As a result, a textured shape 12 corresponding to the forming mold 105 is imparted to the surface 11 a of the laminated sheet material 11 by vacuum molding.

[0048] 10, the vacuum suction roll machine 103 has a cylindrical support roller 104, a cylindrical forming die 105 provided on the outside of the support roller 104, and a cylindrical intermediate roller 106 arranged between the support roller 104 and the forming die 105. These rollers are arranged so that their axes are aligned in a direction perpendicular to the conveying direction.

[0049] The support roller 104 can rotate at a predetermined speed by power transmitted from a motor (not shown). A plurality of suction holes 104a are formed through the circumferential surface of the support roller 104, and air can be sucked into the roller through the suction holes 104a by a vacuum pump (not shown).

[0050] The forming die 105 is formed using a surface material (for example, a quilted natural leather product) or the like having a desired uneven shape 12 formed as a prototype, and has unevenness 105a formed on the outer peripheral surface, which is an inverse of the uneven shape 12. Although the shape of the unevenness 105a is shown in a simplified form in Figure 10, the unevenness 105a on the outer peripheral surface of the forming die 105 is formed so as to correspond to all of the uneven shapes 12 formed on the surface of the laminated sheet material 11. The forming die 105 in this embodiment is made of a porous member (porous material), and therefore has approximately uniform breathability over the entire outer peripheral surface.

[0051] The molding die 105 made of a porous member (or porous material) is produced by, for example, a manufacturing method using powder as a raw material, and the porosity, pore diameter, and pore shape can be adjusted by selecting and compounding the raw materials. Here, the molding die will be described.

[0052] The porous ceramic mold 105 is produced by a manufacturing method using powder as a raw material, for example, and the porosity, pore diameter, and pore shape can be adjusted by selecting and compounding the raw materials.

[0053] =Porous Member and Porous Ceramics= The porous member used in this embodiment may be made of a thermosetting resin containing metal powder or a metal, as long as the porosity of the molding die is 20% or more and 60% or less. However, porous ceramics are preferred in terms of durability and processability.

[0054] Porous ceramics may include either oxide ceramics or non-oxide ceramics. Oxide ceramics can be obtained by sintering alumina, zirconia, titania, cordierite, mullite, silica, magnesia, calcia, or the like as part of the material. Non-oxide ceramics can be obtained by sintering silicon nitride, silicon carbide, aluminum nitride, boron nitride, sialon, or the like as part of the material.

[0055] Representative examples of methods for producing porous ceramics using powder are given below: (1) Unsintered Method For example, by subjecting raw material powders that have been pre-sintered at a predetermined temperature to a sintering treatment, the powder particles are not closely packed together when sintered, and are not completely densified, thereby obtaining a sintered body having internal voids. Because the unsintered method does not use powder that would decompose and burn away and become the source of voids, this method alone is not suitable for producing porous ceramics with high porosity. However, the internal voids can be adjusted by the powder material used, making it possible to fine-tune the pore size. Therefore, by using this method in combination with another method, such as method (2), it is suitable for obtaining porous ceramics with the desired pore size.

[0056] (2) The method of using burnt powder as the prototype of pores: When a compact containing powder of organic matter is sintered, the organic matter is burnt away, and the shape of the burnt material becomes the shape of the pores, resulting in a porous ceramic. This method makes it easy to adjust the porosity range over a wide range by changing the shape and amount of the burnt material.

[0057] (3) Foaming and gel casting method: A foaming agent and a gelling agent are added to the slurry, which is foamed by stirring and then solidified by gelation. The solidified material is sintered to obtain a porous material. It is also possible to obtain a porous material without sintering by adding a binder material.

[0058] (4) Freeze-drying method: After freezing the raw material slurry, the ice is sublimated by freeze-drying to obtain a porous molded body in which the ice has become pores. In this method, freezing is performed from a specific direction, which allows directional ice pillars to grow, thereby giving direction to the pore shape.

[0059] (5) Slurry decompression method: The air bubbles present in the slurry are expanded by decompression, followed by drying and sintering to obtain a porous member. By adding a binder material, a porous member can be obtained without sintering.

[0060] (6) Extrusion Molding By extruding the dough-like slurry from a mold, a molded body with through holes, such as a honeycomb structure, can be produced. If the powder shape is anisotropic, the direction of the powder is aligned by the extrusion flow, making it possible to prepare anisotropic porous ceramics.

[0061] (7) Method using a foaming agent A foaming agent that generates gas is mixed into the slurry, and the slurry is solidified under foaming conditions, thereby obtaining a porous molded body in which the gas generated from the foaming agent becomes voids.

[0062] When the molding die used in this embodiment is made of ceramic, one or more of the above methods can be used for its manufacture. However, by using (1) the non-sintering method and (2) the method of using burnt-out powder as the prototype of the pores in combination, the porosity and pore size of the porous ceramic in this embodiment can be adjusted to the desired range.

[0063] =Manufacturing of Porous Ceramic Mold= The manufacturing of the porous ceramic mold will be described in more detail below. The porous ceramic mold can be manufactured by a process including a molding process, a drying process, and a firing process of a mixture obtained in a kneading process in which water is added to a mixture mainly composed of a heat-resistant inorganic material and optionally containing a binder (including inorganic binders and organic binders) to prepare an aqueous mixture.

[0064] ==Kneading Process== The inorganic binder is a material that becomes a ceramic component during the firing process and binds the inorganic materials together. Examples of inorganic binders include glass frit, colloidal silica, alumina sol, silica sol, sodium silicate, titania sol, lithium silicate, and water glass.

[0065] The heat-resistant inorganic material is a fibrous or particulate material that does not substantially melt or deform during the kneading process to the firing process.

[0066] Examples of fibrous heat-resistant inorganic materials include alumina-silica fibers, alumina fibers, chrysotile, carbon fibers, glass fibers, slag wool, silica fibers, zirconia fibers, gypsum whiskers, silicon carbide fibers, potassium titanate whiskers, aluminum borate whiskers, high silica fiber, fused silica fiber, rock wool, ceramic fibers, hollow ceramics, mullite fibers, and alumina-silica fibers.

[0067] Examples of particulate heat-resistant inorganic materials include particulate materials such as clay, calcium carbonate, talc, silica, aluminum, magnesium oxide, calcium oxide, zirconia, titania, sepiolite, kaolin, zeolite, silicon nitride, aluminum nitride, aluminoborosilicate, aluminosilicate, and porous carbon.

[0068] The heat-resistant inorganic material may contain fibrous heat-resistant inorganic material or particulate heat-resistant inorganic material, or both fibrous heat-resistant inorganic material and particulate heat-resistant inorganic material in any ratio. The pore size of the porous ceramic can be adjusted by the type and size of the fibrous heat-resistant inorganic material.

[0069] The organic binder and water-resistant organic material are added for the purposes of adjusting the plasticity of the slurry during the molding stage, improving strength, etc., but are burned off during the firing process. Therefore, by adjusting the amount of these components, the porosity can be adjusted to a large extent within a desired range.

[0070] Examples of organic binders include methyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, phenol resin, polyacrylic ester, sodium polyacrylate, acrylic resin, vinyl acetate resin, polyvinyl alcohol resin, epoxy resin, and corn starch.

[0071] The kneading step is a step of mixing predetermined amounts of the heat-resistant inorganic material, inorganic binder, organic binder, water-resistant organic material, and other additives with water to form a uniform aqueous dispersion. The amount of water used in the kneading step is adjusted so that the mixture is suitable for the subsequent molding step.

[0072] As the kneading device used in the kneading step, a known kneading device can be used, for example, an extruder or a pressure kneader.

[0073] ==Molding Process== In the molding process, a ceramic mold is created by transferring a quilting pattern made of genuine leather (natural leather) that has actually been created. More specifically, this can be done by the following steps: (1) A genuine leather product with a quilting pattern (prototype product) is created. (2) A negative pattern is created by transferring the quilting pattern from (1) using rubber or the like. To create a faithful negative pattern, it is preferable to use silicone rubber. The silicone rubber negative pattern may be in the form of a strip. In the following steps, since transferring silicone rubber to silicone rubber will cause the silicone rubber to adhere, transfer is repeated with another resin material interposed. (3) The negative pattern obtained in (2) is transferred to create a PVC positive pattern. (4) The positive pattern obtained in (3) is transferred to create an epoxy resin negative pattern Ne. (5) Multiple epoxy resin negative patterns Ne from (4) are linked to form larger units. (6) A silicone rubber positive pattern Ps1 corresponding to the epoxy resin large units connected in (5) is created (FIG. 11(a)). (7) The silicone rubber positive pattern Ps1 is curved and placed on the inner wall of a cylindrical frame (cylinder Cy) (placed so that the positive pattern Ps1 faces inward, FIGS. 11(b) and (c)). (8) Molten PVC is poured into the space inside the cylinder Cy (around the rotation axis) while rotating the cylinder Cy around the shaft Sh to apply centrifugal force, thereby creating a PVC negative master NM. The PVC negative master NM is carefully shaped to complete the PVC negative master NM (FIG. 11(c)). (9) The PVC negative master NM obtained in (8) is mounted in a cylinder Cy, and silicone rubber is poured into the space between the PVC negative master NM and the inner wall of the cylinder Cy (not shown), to produce a silicone rubber positive pattern Ps2. (10) The silicone rubber positive pattern Ps2 obtained in (9) is mounted in a cylinder Cy, and while rotating the cylinder Cy to apply centrifugal force, the raw material mixture obtained in the kneading step is poured into the space inside the cylinder Cy (around the rotation axis), to produce a ceramic raw material compact or a mold precursor (pre-fired mold) 105A (FIG. 11(d)).

[0074] In the series of processes for producing the prototype product, silicone rubber negative pattern, PVC positive pattern, epoxy resin negative pattern Ne, silicone rubber positive pattern Ps1, PVC negative master NM, silicone rubber positive pattern Ps2, and mold precursor 105A as described above, transfer is repeated with other resin materials interposed to prevent the silicone rubbers from adhering to each other when transferred; however, the process can be simplified by using silicone rubbers of different compositions that do not easily adhere to each other.

[0075] Drying Process The drying process, which precedes the subsequent firing process, typically involves drying the molded body at room temperature or at a heated temperature to remove moisture and harden the molded body to establish its shape. The heating temperature is typically 200°C or lower, and preferably around 110°C, at which moisture evaporates gently and easily. The drying time can vary depending on the shape of the molded body and the heating temperature, but is typically around 0.5 to 15 hours.

[0076] == Firing Step == The firing step is preferably divided into a preliminary firing step and a final firing step. The preliminary firing step is usually carried out in the atmosphere to prevent the occurrence of cracks due to the rapid disappearance of the particulate organic matter in the subsequent final firing step at high temperatures, and is usually carried out at 150 to 400°C. The preliminary firing time varies depending on the shape of the molded body and the heating temperature, but is usually about 10 to 70 hours.

[0077] The final firing step is typically performed at a high temperature of 400 to 1000°C to completely remove any remaining particulate organic matter and organic binder, and then melt the inorganic binder to integrate the entire product. The heating time for the final firing step varies depending on the shape of the compact, the heating temperature, the material components used, the compounding ratio, etc., but is typically about 0.5 to 24 hours. This completely burns off the water-resistant organic material, the organic binder, and other organic components, thermally melts the inorganic binder, and integrates it with the heat-resistant inorganic material to obtain a porous ceramic fired product essentially composed of inorganic components, i.e., the porous ceramic molding die 105 used in the laminate sheet manufacturing method according to this embodiment.

[0078] The ceramic molded body described above shrinks by about 5% in length during the firing process, so it is produced taking into account this shrinkage rate so that it will be of a size that can be loaded into a vacuum forming machine after firing.

[0079] Alternatively, a 3D scanner can be used to obtain three-dimensional data of the quilting pattern of a genuine leather product, and the raw material slurry can be used to form a molded product using a 3D printer. In this case, the viscosity of the slurry can be adjusted by changing the water content so that it can be discharged using a 3D printer.

[0080] The average pore diameter of the porous ceramic mold 105 may be 10 μm or more and 40 μm or less, and preferably 15 μm or more and 30 μm or less. The pore diameter is the median value measured by a mercury porosimeter. By having an average pore diameter within the above range, uniform vacuum suction can be more reliably performed over the entire outer surface of the mold, enabling molding that faithfully corresponds to the mold even if the uneven shape 12 is complex. Furthermore, by having an average pore diameter within the above range, the reproducibility of fine patterns is improved, particularly the reproduction of fine lines. Note that an average pore diameter value of 10 μm or more can improve the reproducibility of fine patterns and improve mold release during molding, while an average pore diameter of 40 μm or less enables molding that faithfully corresponds to the mold. If the average pore diameter is below 2 μm, the reproducibility of fine patterns is significantly reduced.

[0081] The pore size distribution preferably has a single peak in the range of 10 μm to 40 μm. This results in a sharper pore size distribution and suppresses variations in pore size depending on the location, thereby more reliably achieving uniform vacuum suction over the entire outer peripheral surface of the mold and improving the effect of enabling molding that faithfully conforms to the mold. In order to achieve a pore size distribution with a single peak in the range of 10 μm to 40 μm, the particle size of the powder of the burnable organic matter, etc. and the particle size of the powder that does not burn can be made uniform, and the internal voids can be made uniform, thereby adjusting the pore size distribution.

[0082] The porous ceramic mold 105 used in the molding step (S30) preferably has a porosity (open porosity) of 20% or more and 60% or more. The porosity may more preferably be 30% or more and 60% or less. A porosity of 20% or more ensures uniform vacuum suction over the entire outer peripheral surface of the mold, improving the effect of enabling molding that faithfully conforms to the mold even if the uneven shape 12 is complex. Furthermore, a porosity of 60% or less ensures the strength of the mold. The porosity (open porosity) can be measured using the Archimedes method.

[0083] The molding step (S30) will be described further with reference to Fig. 10 again. As shown in Fig. 9, the intermediate roller 106 is a metal roller having an inner tube 106a that contacts the support roller 104 and an outer tube 106b that contacts the forming die 105, with a space provided between the inner tube 106a and the outer tube 106b. Both the inner tube 106a and the outer tube 106b are formed with air vents (not shown) that penetrate in the radial direction, allowing air to pass through when sucked into the support roller 104.

[0084] As shown in FIG. 10 , the laminated sheet material 11 is conveyed with its surface 11 a facing the mold 105 and comes into contact with the rotating mold 105. The vacuum pump sucks air into the support roller 104 via the support roller 104, intermediate roller 106, and mold 105 in this order. As the air is sucked, a reduced pressure or vacuum is created between the mold 105 and the surface 11 a of the laminated sheet material 11 in contact with the mold 105, so that the surface 11 a of the laminated sheet material 11 adheres closely to the outer peripheral surface of the mold 105. As a result, the surface 11 a of the laminated sheet material 11, including the softened skin layer 24, deforms along the irregularities 105 a formed on the mold 105, forming an irregular shape 12 on the front side of the laminated sheet material 11. Furthermore, as the support roller 104 rotates, the laminated sheet material 11 is conveyed and released from the mold.

[0085] The intermediate roller 106 may have a cooling pipe 106c between the inner pipe 106a and the outer pipe 106b through which cooling water passes. The cooling water is supplied from a cooling water supply device (not shown) and circulates through the cooling pipe 106c. A second cooling pipe may be disposed inside the support roller 104 and connected to the cooling pipe 106c, so that cooling water also circulates inside the support roller 104. In this manner, the forming die 105 is cooled by the cooling water passing through the cooling pipe 106c. In other words, the vacuum suction roll machine 103 according to the illustrated embodiment can vacuum-suction the laminated sheet material 11 while cooling the forming die 105. The temperature of the cooling water is preferably set to 15°C to 20°C. The laminated sheet material 11 is preferably cooled to 80°C or less.

[0086] The vacuum suction roll machine 103 used in the forming process has a hollow cylindrical forming die 105 as described above, and is capable of continuously forming the uneven shape 12 on the long strip-shaped laminated sheet material 11. However, the shape of the forming die 105 is not limited to this, and it may also have a flat forming die, for example. In this case, it is preferable that the long strip-shaped laminated sheet material 11 is cut in advance to a size that can be sucked into the flat forming die. Then, the cut laminated sheet materials 11 of a predetermined size are intermittently vacuum-formed one by one.

[0087] (S40: Hardening step (see Figures 9 and 12)) In the hardening step, the temperature of the laminated sheet material 11, which has been heated in the molding step and has the uneven pattern 12 formed on its surface 11a, is lowered to stabilize the uneven pattern 12. In the hardening step, for example, the laminated sheet material 11 is cooled. More specifically, the laminated sheet material 11 is placed around a plurality of cooling rollers 107, 107, ... (three in Figure 9) and cooled while being transported while being brought into contact with the plurality of cooling rollers 107, 107, ... in turn. As a result, the laminated sheet material 11 is hardened to become the laminated sheet 10. Note that the hardening step can be carried out by leaving the laminated sheet 11 at room temperature, for example; however, by actively cooling the laminated sheet 11, the laminated sheet 10 can be obtained in a shorter time.

[0088] As shown in FIG. 9 , the cooling rollers 107 are arranged along the conveying direction of the laminated sheet material 11. The laminated sheet material 11 with the concave-convex pattern 12 is conveyed so that the front surface 11a and the back surface 11b sequentially contact the cooling rollers 107, and the front surface 11a and the back surface 11b are sequentially cooled. The number of cooling rollers 107 can be set depending on the material constituting the laminated sheet material 11, the temperature setting of the apparatus up to the molding process, etc. Furthermore, the number of cooling rollers 107 installed during operation or the number of cooling rollers 107 that the laminated sheet material 11 comes into contact with can be adjusted depending on the state of the laminated sheet material 11 upon completion of curing, etc. For example, if it is determined that the laminated sheet material 11 is not sufficiently cured by measuring the surface temperature of the laminated sheet material 11, the number of cooling rollers 107 that the laminated sheet material 11 comes into contact with can be increased to promote curing. In addition, when it is determined that the laminated sheet material 11 has been sufficiently hardened, the number of cooling rollers 107 that come into contact with the laminated sheet material 11 can be reduced to suppress cooling of the laminated sheet material 11 and prevent the laminated sheet material 11 from hardening too much.

[0089] As shown in FIG. 12 , each cooling roller 107 includes a cylindrical support roller 107a, a cooling pipe 107b provided outside the support roller 107a, and a refrigerant passage 107c formed between the support roller 107a and the cooling pipe 107b. The support roller 107a can rotate at a predetermined speed by power transmitted from a motor (not shown). The cooling pipe 107b is a metal pipe, such as stainless steel, against which the laminated sheet material 11 having the uneven surface 12 formed thereon is pressed. The cooling pipe 107b may face either the front surface 11a (the side on which the uneven surface 12 is formed) or the back surface 11b of the laminated sheet material 11. However, having the front surface 11a of the laminated sheet material 11 facing the cooling pipe 107b is preferable because it promotes surface cooling and quickly stabilizes the uneven surface 12. The outer surface of the cooling pipe 107b is mirror-finished. Coolant passage 107c is supplied with cooling water from a cooling water supply device (not shown).

[0090] In this way, the cooling roller 107 performs heat exchange between the cooling water and the laminated sheet material 11 via the cooling pipe 107b, thereby cooling the laminated sheet material 11. The cooled laminated sheet material 11 hardens to become the laminated sheet 10, which is then wound into a roll, completing the production of the laminated sheet 10.

[0091] In a conventional method for manufacturing a laminate sheet, a cushion material 30 is attached to a synthetic resin sheet 20 in advance to prepare a laminate sheet material 11, and then a concave-convex shape 12 is formed on a surface 11a of the laminate sheet material 11 by heat pressing (hereinafter referred to as a "first conventional manufacturing method"). In the first conventional manufacturing method, as shown in Fig. 13, a mold 110 for heat pressing is pressed against the surface 11a of the softened laminate sheet material 11, thereby forming the concave-convex shape 12 on the surface 11a, and a laminate sheet 10' is obtained.

[0092] However, with the manufacturing method according to the first prior art, when the mold 110 is pressed against the laminated sheet material 11, a gap S may form between the recesses 110a formed in the mold 110 and the laminated sheet material 11, trapping air. As a result, the corners K of the protrusions 12a of the uneven shape 12 cannot be tightly fitted to the mold 110. In this case, the corners K sag, making it difficult to obtain a shape that faithfully matches the shape of the recesses 110a of the mold 110. For example, even if the cross-sectional contour of the recesses 110a of the mold 110 has a sharp apex, the surface 11a of the laminated sheet material 11 cannot follow such a contour, making it difficult to obtain a sharp edge at the corners K. Furthermore, when the size (width, etc.) of the uneven shape 12 is small, for example, when the uneven shape is as fine as a fine seam, it becomes difficult to create the uneven shape 12. Thus, with the manufacturing method according to the first prior art, it was difficult to create an uneven shape 12 that faithfully matches the contours of the mold.

[0093] In contrast, in the laminate sheet manufacturing method according to this embodiment, the laminate sheet material 11 is vacuum-suctioned from the front side through a mold. Therefore, even if the concave and convex portions of the mold are small or have a complex shape, the mold and the surface 11a of the laminate sheet material 11 can be brought into close contact with each other without any gaps, so that a concave and convex shape 12 that faithfully corresponds to the mold can be obtained. For example, even if the height of the convex portions 12a included in the concave and convex shape 12 is high, if the cross-sectional contour of the convex portions 12a has sharp vertices, or if the concave and convex portions are minute in size, the desired concave and convex shape can be obtained.

[0094] In the prior art, a method (hereinafter referred to as the "second prior art manufacturing method") can be considered in which the uneven pattern 12 is first formed on the synthetic resin sheet 20 by vacuum forming, and then a cushioning material 30 having a synthetic resin foam 31 is attached to the back surface (back surface 21b of the base fabric layer 21) of the synthetic resin sheet 20. In the second prior art manufacturing method, it is necessary to attach the synthetic resin sheet 20 with the uneven pattern 12 to the surface 30a of the flat cushioning material 30, as shown in Figure 14.

[0095] However, when the synthetic resin sheet 20 is placed on the surface 30a of the cushion material 30, the backside of the convex portions 12a of the concave-convex shape 12 formed on the synthetic resin sheet 20 becomes hollow, creating gaps S. For this reason, in order to bond the synthetic resin sheet 20 and the cushion material 30, it becomes necessary to press the synthetic resin sheet 20 against the cushion material 30, and in this process, the convex portions 12a may be crushed. Therefore, with the manufacturing method according to the second prior art, the concave-convex shape 12 may end up being flatter than the desired concave-convex shape (the height of the concave-convex shape may be lower).

[0096] In contrast, in the method for manufacturing a laminated sheet according to this embodiment, the synthetic resin sheet 20 and the cushion material 30 are bonded together to form a laminated sheet material, and then the uneven shape is imparted. Therefore, the synthetic resin sheet 20 and the cushion material 30 can simultaneously deform into uneven shapes. Therefore, the cushion material 30 can deform in accordance with the deformation of the synthetic resin sheet 20, and therefore, pressure is applied in the thickness direction of the synthetic resin sheet 20 when the cushion material 30 is bonded, which prevents the uneven shape of the synthetic resin sheet 20 from being damaged.

[0097] <Production of Laminated Sheet> [Example 1] First, a mold used to produce a laminated sheet was prepared using raw materials with the composition shown in Table 1 (described below). Specifically, a mixture of 100 parts by weight of glass fiber as a particulate heat-resistant inorganic material (solid content), 20 parts by weight of colloidal silica, 80 parts by weight of glass frit as an inorganic binder, and 15 parts by weight of methyl cellulose as an organic binder was further mixed with 150 parts by weight of water and kneaded in an extruder to obtain a slurry-like mixture. This slurry-like mixture was molded into the shape of the mold and fired to produce a porous ceramic mold. The mold was prepared using a genuine leather product with a surface texture as described with reference to Figures 1 to 4 as a prototype, using the method described with reference to Figure 11.

[0098] The prototype of the genuine leather product had a quilted pattern in which threads were sewn in straight lines at a constant pitch in both the vertical and horizontal directions, with raised portions formed between the threads. The dimension of the porous ceramic mold corresponding to the thickness of the threads on the prototype (corresponding to h2 in Figure 3) was approximately 0.5 mm, and the areas where the threads were transferred were spaced at a 3 cm pitch (corresponding to P in Figure 3). The dimension corresponding to the height of the raised portions of the prototype (corresponding to h1 in Figure 3) was 5 mm.

[0099] Separately, a 1 mm thick PVC sheet was prepared as the synthetic resin sheet, and a 5 mm thick urethane foam (synthetic resin foam) was prepared as the cushioning material, and the two were bonded together by frame lamination. The surface of the PVC sheet was treated with a resin-containing liquid and provided with a 20 μm thick polyurethane surface treatment layer. The cushioning material had a 500 μm thick base fabric layer provided on the back side of the urethane foam. In the frame lamination process, the entire area of ​​the urethane foam where the PVC sheet would be attached was melted using a burner, and the PVC sheet was bonded to obtain a laminated sheet material.

[0100] The obtained laminated sheet material was softened by heating using a heater as shown in Fig. 9, and then vacuum-molded using a vacuum suction roll machine 103 equipped with the above-mentioned mold as shown in Fig. 9 and Fig. 10. The laminated sheet was then cooled using cooling rollers as shown in Fig. 9 and Fig. 12. This resulted in a laminated sheet having an uneven surface.

[0101] Examples 2 to 9 Molds were prepared in the same manner as in Example 1, except that the composition of the raw materials for the mold was changed as shown in Table 1, and laminate sheets were prepared in the same manner as in Example 1.

[0102] Comparative Example 1 A mold was prepared in the same manner as in Example 1, except that the composition of the raw materials for the mold was changed as shown in Table 1, and a laminate sheet was prepared in the same manner as in Example 1.

[0103] Comparative Example 2 A mold was prepared in the same manner as in Example 1 except that the composition of the raw materials for the mold was changed as shown in Table 1, and a laminate sheet was prepared in the same manner as in Example 1.

[0104] [Comparative Examples 3 and 4] A molding die was prepared and a laminate sheet was prepared in the same manner as in Example 1 and Example 4, respectively, except that the order of the manufacturing steps for the laminate sheet was changed. Specifically, in Comparative Examples 3 and 4, the same molding die as that prepared in Example 1 was used, but a PVC sheet (synthetic resin sheet) alone was first molded using the molding die, and after this molding, urethane foam (cushion material) was attached. In other words, after the preparation step of attaching the cushion material to the back side of the synthetic resin sheet to prepare the laminate sheet material, a molding step of imparting unevenness was performed, and frame lamination as performed in Examples 1 to 9 was not used.

[0105] The characteristics of the mold used in each example were measured, and the resulting products (laminate sheets) were also evaluated. The results are shown in Table 1.

[0106] <Measurement of Mold Properties> The porosity (open porosity) and pore diameter were measured as properties of the prepared mold. The porosity was measured by the Archimedes method using an air specific gravity meter (manufactured by Tokyo Science Co., Ltd.). The average pore diameter was taken as the median diameter measured using a mercury porosimeter (Micromeritics AutoPore V (model 9620)). The measurements were carried out under the following conditions. Mercury used: Recycled mercury Mercury surface tension: 485 dynes / cm Mercury contact angle: 130° Mercury injection pressure: 0.5 psia (0.003 MPa) Measurement pressure: 0.5 to 60,000 psia (0.003 to 414 MPa) Measurement mode: Measure the amount of mercury intrusion at a specified pressure (wait time for equilibration: 10 seconds) *Complies with JIS R 1655:2003 FIG. 15 is a graph showing the relationship between pore size diameter, cumulative intrusion, and incremental intrusion, obtained by measurement of the molding die of Example 1 using a mercury porosimeter.

[0107] <Evaluation of Obtained Product> The obtained product (laminate sheet) was evaluated as follows.

[0108] (Reproduction of raised portions) The resulting laminated sheet was compared with the original genuine leather product (original product) from which the quilting pattern was taken, and an evaluation was made of whether the raised portions (G12a in Figure 3, etc.) in the laminated sheet reproduced the raised portions of the original product. The evaluation criteria were as follows: ◎: The raised portions are faithfully reproduced. The raised portions are elastic and have no problems when touched. ○: The shape of the raised portions is faithfully reproduced, but the raised portions are slightly less elastic when touched. △: Partial depressions have occurred in the raised portions. ×: Multiple depressions have occurred in the raised portions. Note that "the raised portions are faithfully reproduced" means that no depressions are observed in the raised portions, just like in the original product.

[0109] (Changes in protrusions over time) The obtained laminated sheet was stored at 100°C for 100 hours, and then evaluated for changes compared to the state before storage. The evaluation criteria are as follows: ◎: No change in appearance or feel. ○: No change in appearance, but a difference in feel (stress felt weaker when pressed compared to the sample before storage). △: Slight dents occurred. ×: Multiple dents occurred.

[0110] (Reproduction of thread patterns in valleys) The resulting laminated sheet was compared with the original genuine leather product (original product) from which the quilting pattern was taken, and the fine irregularities (M12 in Figure 1, etc.) present in the valleys (grooves, G12b in Figure 1, etc.) between the ridges were evaluated for whether they reproduced the thread patterns of the sewing thread of the original product (whether they looked like sewing threads). Specific evaluation criteria are as follows: ⊚: Even when observed with the naked eye and under a 30x magnification with a loupe, even the twist of the sewing thread was clearly reproduced. ◯: No difference from ⊚ to the naked eye, but under a 30x magnification with a loupe, some loss of twist in the sewing thread was observed. △: Some loss of twist in the sewing thread was observed with the naked eye. ×: When observed with the naked eye, a defect such as unevenness in the thickness of the sewing thread was observed, or multiple loss of twist in the sewing thread was observed with the naked eye. XX: When observed with the naked eye, defects such as uneven thread thickness are observed, and when observed with the naked eye, the thread twist is missing in multiple places.

[0111]

[0112] Table 1 shows that in the examples (Examples 1 to 9) using a porous mold having an average pore diameter of 10 μm or more and 40 μm or less, it was possible to more faithfully reproduce the shape of the original mold, compared to the examples (Comparative Examples 1 and 2) using a porous mold having an average pore diameter outside the above range. This is thought to be because in Examples 1 to 9, suction can be performed uniformly across the entire mold surface, allowing the plastic deformation of the cushioning material to sufficiently follow the deformation of the synthetic resin sheet. It was also found that in the examples (Examples 1 to 9) using a porous mold having an average pore diameter of 10 μm or more and 40 μm or less, the state of the raised portions is less likely to change over time, i.e., less likely to deteriorate over time, compared to the examples (Comparative Examples 1 and 2) using a porous mold having an average pore diameter outside the above range. This is presumably because, in Examples 1 to 9, uniform suction is applied to the entire laminated sheet material during molding, preventing damage to the adhesive surface between the synthetic resin sheet and the cushioning material, and preventing stress from concentrating on a portion of the cushioning material and destroying the internal air bubbles. In this way, the generation of damaged areas is suppressed, and areas that are prone to deterioration over time are eliminated or reduced, so it is presumed that quality can be maintained even when stored at high temperatures, for example.

[0113] Furthermore, it was found that in the examples (Examples 1 to 9) in which a mold having an average pore diameter of 10 μm or more and 40 μm or less was used, the lines in the valleys (grooves) between the raised portions were also reproduced well compared to the example (Comparative Example 2) in which a mold having an average pore diameter of more than 40 μm was used. In Comparative Examples 3 and 4 in which a mold having an average pore diameter of 10 μm or more and 40 μm or less was used but no molding process was performed after the production of the laminated sheet material, good evaluations were not obtained, particularly with regard to the reproduction of the raised portions and changes in the raised portions over time.

[0114] Specific embodiments of the present invention are described below. (Note 1) The embodiment according to Note 1 is a method for producing a laminated sheet including a synthetic resin sheet and a cushioning material laminated in this order from the front side to the back side, and having irregularities on at least the front side, the method including a preparation step of attaching the cushioning material to the back side of the synthetic resin sheet to produce a laminated sheet material, a softening step of heating and softening the laminated sheet material, and a molding step of applying vacuum suction to the front side of the laminated sheet material through a molding die made of porous ceramics to impart irregularities, wherein the molding die has an average pore diameter of 10 μm or more and 40 μm or less.

[0115] According to the aspect of Supplementary Note 1, the laminated sheet material 11 is obtained by previously attaching the cushioning material 30 to the synthetic resin sheet 20, and then the uneven shape 12 is formed on the surface 11a of the laminated sheet material 11. Therefore, the cushioning material 30 is already provided on the backside of the protruding portions 12a formed on the surface 11a. As a result, during vacuum suction, the protruding portions 12a that protrude as the synthetic resin sheet 20 deforms are supported by the cushioning material 30. That is, the cushioning material 30 can deform in accordance with the deformation of the synthetic resin sheet 20. Therefore, the three-dimensional appearance of the protruding portions 12a is not lost, and a clear uneven shape 12 can be formed. More specifically, in the resulting final product (laminate sheet 10), the cushioning material 30 is evenly and closely packed and filled all over the backside of the protruding portions G12a of the large uneven shape G12, resulting in a plump finish. Furthermore, since the synthetic resin sheet 20 and the cushioning material 30 are bonded together in advance before the uneven shape 12 is imparted, the bonding strength between them is high, and the resulting laminated sheet 10 is highly durable and can continuously maintain its plump appearance and elasticity.

[0116] Furthermore, according to this embodiment, vacuum suction (vacuum forming) is used to impart the uneven shape during the molding process. Therefore, the uneven shape 12 can be imparted to the surface 11a of the laminated sheet material 11 while it is tightly and securely attached to the mold 105. This allows for the formation of an uneven shape 12 that faithfully corresponds to the mold or faithfully reproduces the uneven shape of the original product from which the mold was taken, even if the mold has complex unevenness or is small in size. For example, even if an uneven shape with sharp edges between the recesses 12b and the protrusions 12a in cross section is desired, the desired shape can be faithfully imparted. Furthermore, even if high protrusions 12a are desired, crushing of the protrusions 12a can be suppressed. Therefore, even fine uneven shapes 12 can be faithfully formed on the surface 11a of the laminated sheet material 11.

[0117] In this embodiment, the mold 105 used in the molding process is made of a porous material. This allows air to be drawn almost evenly from the entire outer peripheral surface of the mold 105 during the molding process. This allows the laminated sheet material 11 to be evenly adhered to the mold 105, faithfully reflecting the mold's irregularities on the surface 11a of the laminated sheet material 11. For example, irregularities with sharp edges can be reflected in the irregular shape 12 of the laminated sheet material 11. Furthermore, ceramics are materials with higher heat resistance and hardness than other materials such as metals and resins. Therefore, by using a mold made of porous ceramics, the mold 105 is less likely to undergo thermal expansion even at high temperatures, has high shape stability, and is less likely to deform due to impact. Furthermore, because the material is ceramic, it is easy to form fine pores throughout the material, making it easy to achieve uniform breathability throughout the mold 105.

[0118] Furthermore, by setting the average pore diameter of the mold made of a porous material to 10 μm or more and 40 μm or less, uniform suction can be more reliably achieved from the entire outer surface of the mold. This further improves the effect of the cushioning material being able to deform in response to the deformation of the synthetic resin sheet. This allows for the formation of unevenness that more faithfully reflects the unevenness of the original product or the unevenness of the mold, thereby improving the reproducibility of fine patterns, especially the reproducibility of fine stitching. The strength of the mold can also be ensured. Furthermore, by enabling more uniform suction as described above, stress generated at the bonding position between the synthetic resin sheet and the cushioning material during molding can be prevented, which could damage the bonded area, or stress concentration in a portion of the cushioning material could cause the internal air bubbles to collapse. Damage to the laminate sheet accelerates deterioration over time from that point. However, by suppressing the generation of such damage according to this embodiment, deterioration over time is reduced compared to conventional products, even with long-term use. Furthermore, even when the product is stored at a temperature higher than room temperature (for example, in an environment of 40° C. or higher, 60° C. or higher, or 80° C. or higher), changes (deterioration) over time can be delayed.

[0119] (Supplementary Note 2) In the embodiment according to Supplementary Note 2, the average pore size of the molding die is 15 μm or more and 30 μm or less.

[0120] According to the aspect of Supplementary Note 2 above, it is possible to more reliably perform uniform vacuum suction over the entire outer peripheral surface of the forming mold, and the effect of being able to form a shape that faithfully corresponds to the forming mold even if the uneven shape 12 is complex can be further improved.

[0121] (Supplementary Note 3) In the aspect according to Supplementary Note 3, the porosity of the mold is 20% or more and 60% or less.

[0122] According to the aspect of Supplementary Note 3, it is possible to more reliably perform uniform vacuum suction over the entire outer peripheral surface of the forming mold, thereby improving the effect of enabling molding that faithfully corresponds to the forming mold even if the uneven shape 12 is complex. It is also possible to improve the effects of reducing changes (deterioration) in the uneven shape over time and ensuring the strength of the forming mold.

[0123] (Supplementary Note 4) In the aspect according to Supplementary Note 4, the preparation step is performed by frame lamination.

[0124] According to the aspect of Supplementary Note 4, the synthetic resin sheet and the cushioning material can be attached without using adhesive. This hardens the adhesive surfaces (the back surface of the synthetic resin sheet 20 and the front surface of the cushioning material 30), preventing the laminated sheet material 11 and, ultimately, the final laminated sheet 10 from hardening. Furthermore, the presence of a hard adhesive layer within the laminated sheet can prevent the desired uneven deformation during the molding process (unevenness-imparting process). For example, when imparting a complex, particularly fine, uneven shape, a hardened adhesive layer can cause ruptures within or near that layer, preventing the cushioning material 30 from following the deformation of the synthetic resin sheet 20. However, this aspect can prevent such a situation.

[0125] (Supplementary Note 5) In the aspect according to Supplementary Note 5, the molding step is carried out while the molding die is cooled.

[0126] According to the aspect of Supplementary Note 5, it is possible to promote a decrease in the temperature of the surface 11a of the laminated sheet material 11 in the molding process. As a result, sagging of the concave-convex shape 12 is suppressed, and even if the desired concave-convex shape 12 includes sharp edges, it is possible to obtain the concave-convex shape 12 that more reliably reflects the shape of the molding die.

[0127] (Supplementary Note 6) In the aspect according to Supplementary Note 6, the softening step heats at least the front side of the laminated sheet material by increasing the heating temperature stepwise or gradually.

[0128] According to the aspect of Supplementary Note 6, the temperature of the laminated sheet material 11 can be gradually increased as it is conveyed, thereby preventing uneven heating. This prevents partial softening of the synthetic resin sheet 20, prevents wrinkles from forming on the surface 11 a, and allows the entire laminated sheet material 11 to be softened evenly while maintaining the surface 11 a smooth.

[0129] (Appendix 7) In an aspect according to Appendix 7, the unevenness of the laminated sheet includes grooves recessed from the front side to the back side, and linear fine unevenness extending along the bottom of the grooves.

[0130] According to the aspect of Supplementary Note 7, it is possible to realize a more aesthetically pleasing design, for example, a pattern that imitates quilting.

[0131] (Supplementary Note 8) In an aspect according to Supplementary Note 8, the synthetic resin sheet is synthetic leather including a surface layer containing polyvinyl chloride and a surface treatment layer formed on the surface side of the surface layer.

[0132] According to the aspect of Supplementary Note 8, the surface 11 a of the laminated sheet material 11 can be made harder than when, for example, the synthetic resin sheet 20 is synthetic leather containing polyurethane in the skin layer 24. As a result, when forming the uneven shape 12 in the molding process, it is possible to more reliably form the uneven shape 12 with sharp edges, and to form a clear uneven shape 12, compared to when the synthetic resin sheet 20 is synthetic leather containing polyurethane in the skin layer 24. Furthermore, even when using a synthetic resin sheet made of such a relatively hard material, vacuum suction is used in the molding process in this aspect, so the synthetic resin sheet can adhere to the molding die, allowing for more reliable formation of unevenness on the surface 11 a of the laminated sheet material 11.

[0133] (Supplementary Note 9) In the aspect according to Supplementary Note 9, the synthetic resin sheet further includes a base fabric layer on the back side of the skin layer.

[0134] According to the aspect of Supplementary Note 9, the strength and shape stability of the synthetic resin sheet can be improved. The synthetic resin sheet having a base fabric layer is suitable for use in applications that require continuous force, such as as a covering material for vehicle seats (car seats).

[0135] (Supplementary Note 10) In the aspect according to Supplementary Note 9, the cushioning material includes a synthetic resin foam containing polyurethane.

[0136] According to the aspect of Supplementary Note 10, when the laminated sheet material 11 is vacuum-suctioned, the cushion material 30 can be smoothly deformed in accordance with the deformation of the synthetic resin sheet 20. Therefore, the cushion material 30 can appropriately support the back side of the protrusion 12 a.

[0137] Furthermore, because the cushioning material has a polyurethane foam resin on the front side, the surface can be easily melted during the frame lamination process in the preparation process. Furthermore, even after bonding the synthetic resin sheet and the cushioning material, the elasticity of the interface between them is maintained. Therefore, during the molding process, flexible deformation is possible to fit the mold, and even complex uneven shapes can be faithfully reflected on the surface of the laminated sheet.

[0138] (Appendix 11) An aspect according to Appendix 11 is an apparatus for manufacturing a laminated sheet which includes a synthetic resin sheet and a cushioning material laminated in this order from the front side to the back side, and which has irregularities on at least the front side, the apparatus including: a preparation unit which attaches the front side of the cushioning material to the back side of the synthetic resin sheet to prepare a laminated sheet material; a softening unit which heats and softens the laminated sheet material; and a molding unit which imparts irregularities to the laminated sheet material by vacuum suction from the front side of the laminated sheet material through a molding die made of a porous member, and the porosity of the molding die is 20% or more and 60% or less.

[0139] According to the aspect of Supplementary Note 11, the same effects as those obtained by the aspect of Supplementary Note 1 can be obtained.

[0140] (Appendix 1A) An aspect according to Appendix 1A is a method for manufacturing a laminated sheet that includes a synthetic resin sheet and a cushioning material laminated in this order from the front side to the back side, and that has irregularities on at least the front side, the method including: a preparation step of attaching the cushioning material to the back side of the synthetic resin sheet to produce a laminated sheet material; a softening step of heating and softening the laminated sheet material; and a molding step of applying vacuum suction from the front side of the laminated sheet material through a molding die made of a porous member to impart irregularities, wherein the porosity of the molding die is 20% or more and 60% or less.

[0141] (Appendix 2A) An embodiment according to Appendix 2A is the method for producing a laminate sheet according to Appendix 1A, in which the mold made of the porous member is a mold made of porous ceramics.

[0142] (Appendix 3A) An aspect according to Appendix 3A is the method for producing a laminated sheet according to Appendix 1A, in which the preparation step is performed by frame lamination.

[0143] (Appendix 4A) An aspect according to Appendix 4A is the method for producing a laminate sheet according to Appendix 1A or Appendix 2A, wherein the average pore size of the mold is 5 μm or more and 40 μm or less.

[0144] (Appendix 5A) An aspect according to Appendix 5A is the method for producing a laminate sheet according to Appendix 1A or Appendix 2A, wherein the molding step is performed while the mold is cooled.

[0145] (Appendix 6A) An aspect according to Appendix 6A is the method for producing a laminate sheet according to Appendix 1A or Appendix 2A, in which the softening step heats at least the front side of the laminate sheet material by increasing the heating temperature stepwise or gradually.

[0146] (Appendix 7A) In an aspect according to Appendix 7A, there is provided the method for producing a laminate sheet according to Appendix 1A or Appendix 2A, wherein the unevenness of the laminate sheet includes grooves recessed from the front side to the back side, and linear fine unevenness extending along the bottom of the grooves.

[0147] (Appendix 8A) An aspect according to Appendix 8A is the method for producing a laminate sheet according to Appendix 1A or Appendix 2A, in which the synthetic resin sheet is synthetic leather including a surface skin layer containing polyvinyl chloride and a surface treatment layer formed on the surface side of the surface skin layer.

[0148] (Appendix 9A) An aspect according to Appendix 9A is the method for producing a laminated sheet according to Appendix 8A, in which the synthetic resin sheet further includes a base fabric layer on the back side of the skin layer.

[0149] (Appendix 10A) An aspect according to Appendix 9A is the method for producing a laminated sheet according to Appendix 1A or Appendix 2A, in which the cushioning material includes a synthetic resin foam containing polyurethane.

[0150] (Appendix 11A) An aspect according to Appendix 11A is an apparatus for manufacturing a laminated sheet that includes a synthetic resin sheet and a cushioning material laminated in this order from the front side to the back side, and that has irregularities on at least the front side, the apparatus including: a preparation unit that attaches the front side of the cushioning material to the back side of the synthetic resin sheet to prepare a laminated sheet material; a softening unit that heats and softens the laminated sheet material; and a molding unit that imparts irregularities to the laminated sheet material by vacuum suction from the front side of the laminated sheet material through a molding die made of a porous member, and the porosity of the molding die is 20% or more and 60% or less.

[0151] Although the present invention has been described above based on specific embodiments and examples, these embodiments and examples are presented only as examples, and the present invention is not limited to the above embodiments and examples. Various changes, modifications, substitutions, deletions, additions, combinations, etc. are possible within the scope of the disclosure of the present invention.

[0152] This application claims priority based on Japanese Patent Application No. 2023-134236, filed on August 21, 2023, the entire contents of which are incorporated herein by reference.

[0153] REFERENCE SIGNS LIST 10 Laminated sheet 11 Laminated sheet material 11a Surface of laminated sheet material 11b Back surface of laminated sheet material 12 Concave-convex shape 12a Convex portion 12b Concave portion 20 Synthetic resin sheet 21 Base fabric layer 21b Back surface of base fabric layer 24 Skin layer 25 Surface treatment layer 30 Cushion material 31 Synthetic resin foam 32 Back base fabric layer 105 Molding mold G12 Large concave-convex shape G12a Raised portion G12b Groove M12 Fine concave-convex shape M12a Convex portion of fine concave-convex shape M12b Concave portion of fine concave-convex shape

Claims

1. A method for producing a laminated sheet comprising a synthetic resin sheet and a cushioning material laminated in this order from front to back, and having irregularities on at least the front side, comprising: a preparation step of attaching the cushioning material to the back side of the synthetic resin sheet to produce a laminated sheet material; a softening step of heating and softening the laminated sheet material; and a forming step of imparting irregularities to the front side of the laminated sheet material by vacuum suction through a forming mold made of porous ceramics, wherein the average pore diameter of the forming mold is 10 μm or more and 40 μm or less.

2. The method for producing a laminate sheet according to claim 1, wherein the average pore size of the mold is 15 μm or more and 30 μm or less.

3. The method for producing a laminate sheet according to claim 1, wherein the porosity of the mold is 20% or more and 60% or less.

4. A method for producing a laminated sheet according to any one of claims 1 to 3, wherein the preparation step is carried out by frame lamination.

5. A method for producing a laminated sheet according to any one of claims 1 to 3, wherein the molding step is carried out while the mold is cooled.

6. A method for producing a laminate sheet according to any one of claims 1 to 3, wherein the softening step includes heating at least the front side of the laminate sheet material by increasing the heating temperature stepwise or gradually.

7. A method for manufacturing a laminated sheet as described in any one of claims 1 to 3, wherein the unevenness of the laminated sheet includes grooves recessed from the front side to the back side and linear fine unevenness extending along the bottom of the grooves.

8. A method for producing a laminate sheet according to any one of claims 1 to 3, wherein the synthetic resin sheet is synthetic leather comprising a surface layer containing polyvinyl chloride and a surface treatment layer formed on the surface side of the surface layer.

9. The method for producing a laminate sheet according to claim 8, wherein the synthetic resin sheet further comprises a base fabric layer on the back side of the skin layer.

10. A method for producing a laminate sheet according to any one of claims 1 to 3, wherein the cushioning material comprises a synthetic resin foam containing polyurethane.

11. An apparatus for manufacturing a laminated sheet comprising a synthetic resin sheet and a cushioning material laminated in that order from front to back and having irregularities on at least the front side, comprising: a preparation unit for attaching the front side of the cushioning material to the back side of the synthetic resin sheet to prepare a laminated sheet material; a softening unit for heating and softening the laminated sheet material; and a molding unit for imparting irregularities by vacuum suction from the front side of the laminated sheet material through a molding die made of a porous member, wherein the average pore diameter of the molding die is 10 μm or more and 40 μm or less.