JP2024074257A - Manufacturing method and device for manufacturing laminated sheet - Google Patents

Abstract

[Problem] To provide a method for manufacturing a laminated sheet, capable of faithfully forming a concave-convex pattern including fine concave-convex shapes on a laminated sheet material having a cushioning material attached to the back surface of a synthetic resin sheet, using a molding die. [Solution] A method for manufacturing a laminated sheet including a synthetic resin sheet and a cushioning material laminated from front to back in this order, and having concave-convex shapes at least on the front surface, includes a preparation step of attaching the cushioning material to the back surface of the synthetic resin sheet to prepare a laminated sheet material, a softening step of 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 material to impart concave-convex shapes. [Selected Figure] Figure 1

Description

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

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

In addition, a method using a vacuum suction machine (vacuum suction machine) is also known as a method for manufacturing a laminated sheet having an uneven surface (see Patent Documents 3 and 4).

JP 2003-326598 A JP 2019-142231 A Chinese Patent Publication No. 106192432 Chinese Patent Publication No. 103114408

In the manufacturing methods of laminated sheets as described in Patent Documents 1 and 2, even if an uneven shape is created in the laminated sheet material by heat pressing or the like, 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 rounded (gentled) compared to the desired contour that corresponds to the mold, making it difficult to obtain a sharp edge.

In recent years, there has been a demand for more complex patterns of projections and recesses on the surface of laminated sheets, one example of which is a pattern that imitates quilting (also called a quilting pattern). A quilting pattern, for example, includes a mixture of relatively large projections and recesses including raised portions and grooves between the raised portions, and fine projections and recesses that imitate stitching lines (stitches) formed in the grooves of the relatively large projections and recesses. There is also a demand for such complex projection and recess patterns to be formed faithfully to the molding die.

The processing method using vacuum suction (vacuum embossing method) described in Patent Documents 3 and 4 is a method suitable for forming unevenness on the very surface of the outer material. Therefore, for example, fine uneven shapes (shapes that mimic stitching lines) in the above-mentioned quilting pattern can be formed well. However, it is often the case that relatively large uneven shapes in quilting patterns cannot be formed as desired using only the vacuum embossing method. For example, even if the outer material (synthetic resin sheet) is processed using the vacuum embossing method to form an uneven shape and then a cushioning material is attached to the back side, the cushioning material cannot follow the uneven shape of the outer material, and unintended dents (depressions) may occur in the raised parts that should be plump (rising) (Figure 13).

The present invention was made with a focus on the above problems, and aims to provide a method for manufacturing a laminated sheet that can faithfully form a concave-convex pattern, including fine concave-convex shapes, on the surface of a laminated sheet material in which a cushioning material is attached to the back surface of a synthetic resin sheet, in a mold.

In order to achieve the above object, 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 from the front side to the back side, and has irregularities at least on the front side, and includes a preparation step of attaching the cushioning material to the back side of the synthetic resin sheet to prepare a laminated sheet material, a softening step of 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 material to impart irregularities.

As a result, the laminate sheet manufacturing method of the present invention can faithfully form a concave-convex pattern, including fine concave-convex shapes, on the surface of a laminate sheet material in which a cushioning material is attached to the back surface of a synthetic resin sheet, in a mold.

1 is a photograph of a laminate sheet manufactured by a manufacturing method according to one embodiment of the present invention. 2(a) is a plan view of the laminated sheet shown in FIG. 1 as seen from the front side, and FIG. 2(b) is an enlarged view of a portion III in FIG. 2(a). 2 is a cross-sectional view taken along line II in FIG. 1. 2 is a cross-sectional view taken along line II-II of FIG. 1. FIG. 4 is a cross-sectional view corresponding to FIG. 3 of a modified example of the laminated sheet. FIG. 4 is a cross-sectional view corresponding to FIG. 3, but with a relatively large ridge height. FIG. 4 is an explanatory diagram showing a preparation step in a manufacturing method according to an embodiment. FIG. 4 is a cross-sectional view showing a laminated sheet material produced in a preparation process. 3A to 3C are explanatory views showing a softening step, a molding step, and a hardening step in a manufacturing method according to one embodiment. FIG. 2 is a cross-sectional view showing a schematic diagram of a vacuum suction roll machine used in the molding process. FIG. 4 is a cross-sectional view showing a schematic diagram of a cooling roller used in a curing step. FIG. 1 is an explanatory diagram showing a manufacturing method according to the prior art. FIG. 1 is an explanatory diagram showing a manufacturing method according to the prior art. 1 is a photograph of a laminated sheet produced by a conventional manufacturing method, in which an unintended dent has occurred.

A method for manufacturing a laminate sheet according to an embodiment of the present invention will be described below with reference to the drawings. In the following description, the side of the laminate sheet 10 that is exposed when in use is referred to as the "front side", the front surface of each member is referred to as the "surface", the side of the laminate sheet that is not exposed when in use is referred to as the "back side", and the back surface of each member is referred to as the "surface".
will be done.

<Laminated sheet>
The laminated sheet obtained in one embodiment is formed from a laminated sheet material in which a sheet-shaped cushioning material is attached to a synthetic resin sheet. The laminated sheet is a laminated sheet material having a predetermined uneven shape (pattern) on the surface. The laminated sheet is suitably used as a skin material for interior parts (seats, instrument panels, door trims, ceilings, etc.) of automobiles, railway vehicles, and aircraft.

Figure 1 shows a photograph of an example of a laminate sheet taken from the front side. Figure 2 shows a schematic drawing of an enlarged top view of part III in Figure 1. Figure 3 shows a schematic cross-section along line I-I in Figure 2, and Figure 4 shows a schematic cross-section along line II-II in Figure 1.

As shown in Figs. 1 to 4, the laminated sheet 10 according to this embodiment includes a synthetic resin sheet 20 and a cushioning material 30 laminated in this order from the front side to the back side, and is a sheet having irregularities at least on the front side. More specifically, as shown in Figs. 3 and 4, the laminated sheet 10 is formed of a laminated sheet material 11 in which a sheet-shaped cushioning material 30 is attached to the back side of a synthetic resin sheet 20. The cushioning material 30 of the present invention may include a synthetic resin foam 31 and a backing fabric layer 32, or may be formed only from the synthetic resin foam 31 without using the backing fabric layer 32. The total 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 thickness of the synthetic resin foam 31 constituting the cushioning material 30 is 2 mm or more and 10 mm or less, preferably 3 mm or more and 8 mm or less.

As shown in Figures 3 and 4, the synthetic resin sheet 20 may be a sheet including a base fabric layer 21, a surface 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 provided on the surface of a fabric, and the texture resembles that of natural leather.

The base fabric layer 21 may be made of a fabric (fiber aggregate) in the form of nonwoven fabric, woven fabric, knitted fabric, etc. Among these, it is preferable to use woven fabric or knitted fabric because they are inexpensive. The base fabric layer 21 may be a sheet material having a porous structure in which a synthetic resin such as a polyurethane resin is impregnated into the fabric. The base fabric layer 21 has the function of supporting and reinforcing the layer formed on its front side. The provision of the base fabric layer 21 can increase 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.

In this embodiment, the synthetic resin sheet 20 does not necessarily have to have the base fabric layer 21. For example, as shown in the modified example in FIG. 5, the synthetic resin sheet 20 may be composed of a surface layer 24 and a surface treatment layer 25, and the cushioning material 30 may be attached to the back side of the surface layer 24. In a configuration without the base fabric layer 21, the laminated sheet 10 can obtain high deformability, and is therefore preferable in applications where large flexible deformation is required.

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 necessary. The thickness of the skin layer 24 can be appropriately selected 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.

The surface treatment layer 25 is a layer containing a synthetic resin different from the resin constituting the above-mentioned skin layer 24, and can be formed by applying a synthetic resin-containing liquid. The thickness of the surface treatment layer 25 can be appropriately selected according to the purpose, but is preferably 5 μm or more and 20 μm or less, and more preferably 10 μm or more and 20 μm or less. By forming the surface treatment layer 25, a unique texture and feel can be imparted to the surface of the synthetic resin sheet 20, and in particular, when the synthetic resin sheet 20 is made of synthetic leather, a texture (gloss, etc.) and feel similar to natural leather can be imparted. As the above-mentioned synthetic resin, an aqueous polyurethane (PU) resin is preferable, and examples of the polyurethane resin include polycarbonate polyurethane, polyester polyurethane, and polyether polyurethane. The synthetic resin-containing liquid used to form the surface treatment layer 25 is prepared according to the texture, feel, surface friction characteristics, etc. required for the synthetic resin sheet 20. The surface treatment layer 25 may contain additives such as a crosslinking agent and a lubricant as necessary.

The surface treatment layer 25 may be composed of a single layer as shown in FIG. 3, etc., 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.

Furthermore, an intermediate layer may be provided between the base fabric layer 21 and the surface layer 24. The intermediate layer may be attached to the surface side of the base fabric layer 21 via an adhesive layer. The intermediate layer may be made of a foam or a non-foam, and may be made of a synthetic resin foam containing polyvinyl chloride, for example. The intermediate layer may contain additives such as plasticizers, stabilizers, fillers, foaming agents, and flame retardants as necessary. The material and thickness of the intermediate layer may be appropriately set in consideration of the texture and use of the synthetic resin sheet 20.

As shown in Figures 3 and 4, the cushioning material 30 has a sheet-shaped synthetic resin foam 31 and a backing fabric layer 32 laminated on the back side of the synthetic resin foam 31.

The material constituting the synthetic resin foam 31 is not particularly limited, but may be foamed plastic, preferably foamed plastic containing polyurethane. More specifically, the synthetic resin foam 31 may be a so-called soft urethane foam, delaminated urethane foam, or the like, which has interconnected air bubbles and is relatively soft and resilient. The synthetic resin foam 31 is composed of a foam obtained by mixing polyurethane foam as a main component with additives such as a catalyst and a blowing agent, and carrying out a foaming reaction and a resinification reaction. The hardness of the polyurethane-containing synthetic resin foam 31 can be easily adjusted by changing the conditions during production. Therefore, it is possible to appropriately adjust the hardness of the cushion material 30 according to the material and hardness of the synthetic resin sheet 20, the application and specification requirements of the laminated sheet 10, and the like, to form a laminated sheet material 11 that is easy to form an uneven shape 12 on the surface 11a.

The density of the synthetic resin foam 31 is preferably in the range of 0.0200 g/cm ³ or more and 0.050 g/cm ³ or less. Furthermore, the thickness of the synthetic resin foam 31 is preferably 5.0 mm or more, and may be 5.0 mm or more and 20.0 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 detail later). As the synthetic resin foam 31 in this embodiment, a foamed polyurethane sheet having a density of 0.030 g/cm ³ and a thickness of 5.0 mm is used. In this specification, the "density" is a value at 4°C.

The backing fabric layer 32 may be made of the same material as the above-mentioned fabric layer 21. In other words, it may be made of a fabric (fiber aggregate) in which fibers are shaped into a nonwoven fabric, woven fabric, knitted fabric, or the like. The backing fabric layer 32 is not necessarily provided, but the backing fabric layer 32 can increase the strength and shape stability of the cushioning material 30 and, ultimately, the laminated sheet 10. There is no particular limit to the thickness of the backing fabric, and it can be selected appropriately depending on the purpose, but it is preferably 300 μm or more and 1,300 μm or less, and most preferably 400 μm or more and 700 μm or less.

By the method for manufacturing a laminate sheet according to this embodiment, unevenness is formed on the front side of the laminate sheet material 11, thereby obtaining a laminate sheet 10 with a predetermined uneven shape (uneven pattern) 12. The uneven shape given to the laminate sheet 10 is not particularly limited, but may be a pattern in which a plurality of convex portions 12a are formed when viewed along at least one direction perpendicular to the thickness direction, and the spaces between the convex portions 12a are recessed portions 12b. In addition, it is preferable that the uneven shape 12 is one in which the width of the recessed portions 12b is smaller than the width of the protruding portions 12a when viewed along any direction perpendicular to the thickness direction.

In the example shown in Figures 1 to 4, the uneven shape 12 is a pattern that imitates quilting (quilting pattern). Quilting is generally a process of sewing (stabbing) a laminate consisting of two sheets with a cushioning layer sandwiched between them. Therefore, on the surface of a quilted item, linear portions sewn with thread (stitching lines or stitches) are recessed like grooves, and the portions between the stitching lines are raised, forming an uneven shape. The quilting pattern in the laminated sheet 10 may be an uneven pattern that imitates the uneven shape obtained by the quilting process, in other words, an uneven pattern in which the uneven shape obtained by the quilting process is reproduced in the laminated sheet material 11 without sewing.

In the example shown in Figures 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 is 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 said to be depressions that extend linearly in a planar view. Furthermore, at the bottom of the grooves G12b of the large uneven shape G12, finer unevenness (hereinafter also referred to as a fine uneven shape) M12 is formed. The fine uneven shape M12 is a shape in which convex portions M12a and concave portions M12b are alternately arranged along the extension direction of the elongated grooves G12b, as shown in Figures 2 and 4. When the uneven shape formed on the laminated sheet 10 is a quilting pattern, the grooves G12b are parts that imitate depressions formed by stab stitching in a quilted product, and the fine uneven shape M12 is a part that imitates a stitch pattern formed by stab stitching. The protrusions M12a are parts that imitate the places where the thread is exposed on the surface, and the recesses M12b are parts that imitate the places where the thread is inserted inside. In the laminated sheet 10 obtained by the manufacturing method of this embodiment, the uneven shape 12 formed on the front side of the laminated sheet 10 includes the large uneven shape G12 and the fine uneven shape M12 of different sizes as described above. And according to this embodiment, even such a somewhat complicated uneven shape can be formed in one process.

Note that 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.

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. In addition, the groove G12b may be straight or curved in plan view, and may be bent or curved. In addition, since the raised portion G12a is an area surrounded or sandwiched by one or more grooves G12b, it may have various shapes. For example, the plan view shape of one raised portion G12a (plan view shape with the groove G12b as the outer contour) may be approximately square as shown in FIG. 1, or may be a rectangle other than a square, a polygon other than a rectangle, a circle, an ellipse, etc. In addition, multiple raised portions G12a may have the same plan view shape, or may have different plan view shapes from each other.

The height h1 of the raised portion G12a (FIG. 3) may be 1 mm or more and 10 mm or less, and is preferably 3 mm or more and 8 mm or less. When the groove G12b has a fine uneven shape M12 formed therein, the height h1 of the raised portion G12a can 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. When the height h1 of the raised portion G12a is relatively large compared to the thickness of the synthetic resin foam 31, for example, when it is equal to or larger than the thickness of the synthetic resin foam, unevenness may be formed on the back side of the laminated sheet 10 following the rise of the raised portion G12a on the front side of the laminated sheet 10. That is, as shown in FIG. 6, the back base layer 32 may be deformed 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 laminated sheet 10, the cushioning material 30 is sufficiently thick, so that the elasticity of the laminated sheet 10 is not affected. In addition, if the back side of the laminated sheet 10 is made uneven, it is possible to form large raised areas that cannot be obtained by other press molding methods, and the shape of such raised areas is highly stable over time.

The fine uneven shape M12 may be formed at the bottom of the groove G12b. When the uneven shape 12 is a quilting pattern, the fine uneven shape M12 becomes a pattern that looks like a sewing thread (a pattern that reproduces the stitches). The convex portion M12a corresponds to the portion where the sewing thread is exposed on the surface. The surface of the convex portion M12a may further have unevenness that imitates the twist of the sewing thread, for example, as shown in FIG. 2. Note that the twisted pattern of the sewing thread reproduced in the fine uneven shape M12 exemplified in FIG. 2 (not shown in FIG. 4) 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.

When the fine uneven shape M12 is a pattern that reproduces a sewing thread, the width w of the convex portion M12a included in the fine uneven shape M12 may be equal to or smaller than the width W of the groove G12b. The width w (Fig. 2) of the convex portion M12a may be 0.4 mm or more and 1.2 mm or less. The height h2 (Fig. 3) of the convex portion M12a may be 0.4 mm or more and 1.2 mm or less. The height h2 of the convex portion M12a can be said to be a dimension equivalent to the thickness of the reproduced sewing thread.

When the synthetic resin sheet 20 is synthetic leather, the surface of the skin layer 24 may also be formed with a ground pattern that imitates the irregular wrinkles (grain) on the surface of natural leather. The ground 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 ground pattern that imitates grain is about 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). It is also 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).

<Method of manufacturing laminated sheet>
The method for manufacturing a laminated sheet according to this embodiment includes a preparation step (S10) of preparing a laminated sheet material by attaching the cushioning material to the back side of a synthetic resin sheet, a softening step (S20) of softening the laminated sheet material, and a forming step (S30) of providing unevenness by vacuum suction from the front side of the laminated sheet material through a porous ceramic forming die. Furthermore, after the forming step (S30), a hardening step (S40) may be optionally included. Each step will be described below.

(1) Preparation Step (S10, see FIG. 7)
In the preparation step (S10, also referred to as the pasting step or laminated sheet material preparation 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 in a roll. Then, the synthetic resin sheet 20 and the cushion material 30 are set in, for example, a commercially available frame laminator 100 (a preparation unit for preparing a laminated sheet, FIG. 7) equipped with a burner 101.

Next, using a frame laminating machine 100, the surface 31a of the synthetic resin foam 31 of the cushioning 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 the laminated sheet material 11 shown in FIG. 8 to be created in which the synthetic resin sheet 20 and the cushioning material 30 are integrated. As shown in FIG. 8, the surface 11a of the laminated sheet material 11 is the surface of the synthetic resin sheet 20 (the surface of the surface treatment layer 25), and the back surface 11b of the laminated sheet material 11 is the back surface of the cushioning material 30 (the back surface of the back base fabric layer 32). The surface 11a of the laminated sheet material 11 is flat.

Frame lamination is a processing method in which the surface 31a of the synthetic resin foam 31 of the cushioning material 30 is heated and melted using a burner 101 or the like, and then bonded to the synthetic resin sheet 20, which is another base material.

The depth from the outermost surface of the portion melted on the front side of the synthetic resin foam 31 during frame lamination 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 in a plan view (also called the synthetic resin sheet attachment area) is melted. This enhances the unity between the synthetic resin sheet 20 and the cushioning material 30, improving the quality (reproducibility of complex uneven shapes, flexibility) of the resulting laminated sheet 10. However, as long as it is possible to sufficiently reproduce the uneven shapes of the original product or the molding die, especially the raised parts, the synthetic resin sheet attachment area does not necessarily have to be melted in its entirety.

The method of bonding the synthetic resin sheet 20 and the cushion material 30 in the preparation step (S10) is not limited to the above-mentioned frame lamination process, and a method using an adhesive may be used. Methods using an adhesive include a method of applying a fluid adhesive to at least one of the back surface of the synthetic resin sheet 20 and the front surface of the cushion material 30 and then bonding the two together, and a method of placing a sheet-like adhesive such as a hot melt sheet between the synthetic resin sheet 20 and the cushion material 30 and then heating the sheet-like adhesive to soften or melt it to bond the two together. When bonding is performed by separately providing an adhesive in this way, by appropriately selecting the adhesive, it is possible to firmly bond the synthetic resin sheet 20 and the cushion material 30, and a highly durable laminated sheet can be obtained. On the other hand, the above-mentioned frame lamination process is preferable because it does not require the intervention of an adhesive, which is a different material, and it is possible to prevent the adhesive layer from becoming hard and losing the flexibility of the laminated sheet material 11.

As another method, a polyurethane elastomer containing a foaming agent is heated and kneaded, and the resulting resin composition is formed into a sheet by a calendaring method to obtain an unfoamed resin sheet, which is then laminated to a synthetic resin sheet 20 in a heated state, and the foaming agent is foamed at a high temperature of about 200°C to produce a laminated sheet material 11 in which the synthetic resin sheet 20 and the cushioning material 30 are integrated. In this way, the "cushioning material" in this specification may include not only cushioning materials that have high cushioning properties themselves, but also cushioning material precursors that foam when treated by heating, such as the unfoamed resin sheet described above.

As another method, the adhesive surface of the polyurethane foam or the adhesive surface of the base fabric can be softened by plasma treatment or the like before bonding.

(2) Softening step (S20, see FIG. 9)
In the softening step (S20), the obtained laminated sheet material 11 is softened to facilitate the formation of unevenness in the subsequent molding step (S30). The laminated sheet material 11 can be softened by raising the temperature of the laminated sheet material 11. In this case, the laminated sheet material 11 may be heated directly or indirectly. For example, when the laminated sheet material 11 is obtained in a rolled state in the preparation step (S10), the laminated sheet material 11 is pulled out (unwound) and passed through a heater (softening section) 102 set to a predetermined temperature. As a result, the laminated 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 surface 11a of the laminated sheet material 11 is softened by the heater 102 at least up to the skin layer 24. Then, the laminated sheet material 11 with the softened surface 11a is continuously sent to the next step without being wound up.

Here, the heater 102 has a long housing 102a along the conveying direction of the laminated sheet material 11, and multiple heaters 102b, 102b, ... installed in the housing 102a (four heaters in the illustrated embodiment). The length of the housing 102a in the conveying direction is, for example, 12 m, and the heating length of the laminated sheet material 11 is set according to the length of the housing 102a. In addition, the multiple heaters 102b, 102b, ... are each attached to the upper part of the housing 102a (for example, the inner upper surface of the housing 102a) along the conveying direction of the laminated sheet material 11, thereby heating the surface 11a of the laminated sheet material 11. In addition, the heaters 102b, 102b, ... may be attached to the lower part of the housing 102a (the back side of the laminated sheet material 11, for example the inner bottom surface of the housing 102a) 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 both the front and back of the laminated sheet material 11 simultaneously.

The temperature of each heater 102b can be set individually, and the set temperature can be set so that it gradually increases from the sheet inlet 102c side to the sheet outlet 102d side provided in the housing 102a. That is, in the softening process (S20) in this embodiment, the temperature at which the laminated sheet material 11 is heated is set so that it gradually increases along the conveying direction of the laminated sheet material 11. For example, the heating temperature can be set to increase in stages or gradually. The set temperature of each heater 102b is set arbitrarily according to the softening state of the skin layer 24 of the laminated sheet material 11. In one embodiment, the set temperature can be set to 120°C, 140°C, 150°C, and 180°C from the sheet inlet 102c side to the sheet outlet 102d in that order. Furthermore, a heater 102e for keeping warm is installed between the sheet outlet 102d and the vacuum suction roll machine 103 used in the next process, the molding process (S30). The heater 102e for keeping warm heats the surface 11a of the laminated sheet material 11 after it is discharged from the sheet discharge port 102d of the heater 102, and prevents the temperature of the surface 11a of the laminated sheet material 11 from decreasing until it is formed. The heaters 102b, 102b, ... of the heater 102 are used in the temperature range of 120°C to 200°C. The laminated sheet material 11 softened in this way is transported to the subsequent vacuum suction roll machine 103.

(3) Molding step (S30, see FIGS. 9 and 10)
In the forming step (S30, also referred to as the unevenness imparting step), as shown in Fig. 9, the laminated sheet material 11, whose surface 11a including the skin layer 24 has been softened in the softening step (S20), is placed so that the surface 11a faces a vacuum suction roll machine (forming section) 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 11a of the laminated sheet material 11 including the skin layer 24 through a forming die 105 that is made of a porous material and has air permeability. As a result, the unevenness shape 12 corresponding to the forming die 105 is formed on the surface 11a of the laminated sheet material 11 by vacuum forming.

As shown in FIG. 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 combined coaxially and arranged so that their axes are aligned in a direction perpendicular to the conveying direction.

The support roller 104 can rotate at a predetermined speed by power transmitted from a motor (not shown). A number of suction holes 104a are formed through the peripheral 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).

The mold 105 is formed using a skin material (e.g., a natural leather product with quilting) having a desired uneven shape 12 as a prototype, and has unevenness 105a, which is an inverted shape of the uneven shape 12, formed on the outer peripheral surface. In FIG. 10, the shape of the unevenness 105a is simplified, but the unevenness 105a on the outer peripheral surface of the mold 105 has a shape corresponding to all the uneven shapes 12 formed on the surface of the laminated sheet material 11. When the uneven shape to be formed on the laminated sheet material is a combination of relatively large uneven shapes and fine uneven shapes, the unevenness 105a of the mold 105 has a shape corresponding to the pattern of the combination. The mold 105 in this embodiment is formed of a porous member (porous material), for example, porous ceramic, and has almost uniform air permeability over the entire outer peripheral surface. Ceramics are preferable as a material for the mold 105 because they have higher heat resistance and hardness than metals.

The mold 105 made of a porous member (or porous material) is produced, for example, by a manufacturing method using powder as a raw material, and the porosity, pore diameter, pore shape, etc. can be adjusted by selecting and mixing the raw materials. For example, the mold 105 can be produced by forming a flat silicone concave mold based on a flat master model, forming a flat silicone convex mold based on the silicone concave mold, spraying a ceramic solution in which ceramic powder is dissolved in a specified solvent onto the silicone convex mold, and then rolling the silicone convex mold into a cylindrical shape and drying it.

The porosity (open porosity) of the mold 105 may be preferably 20% to 85%, more preferably 30% to 60%. This ensures uniform suction from the entire outer peripheral surface of the mold, improving the effect of the cushioning material being able to deform in accordance with the deformation of the synthetic resin sheet. The porosity can be measured by the Archimedes method. The average pore diameter of the mold 105 may be preferably 5 μm to 55 μm, more preferably 5 μm to 40 μm. Such an average pore diameter can improve the efficiency of vacuum suction and ensure the strength of the mold. The average pore diameter can be measured by a mercury porosimeter.

As shown in FIG. 10, the intermediate roller 106 is a metal roller having an inner tube 106a in contact with the support roller 104 and an outer tube 106b in contact with the mold 105, with a space between the inner tube 106a and the outer tube 106b. The inner tube 106a and the outer tube 106b are each formed with a radially penetrating air hole (not shown), so that the air sucked into the support roller 104 passes through. In addition, the intermediate roller 106 may have a cooling pipe 106c through which cooling water passes between the inner tube 106a and the outer tube 106b. The cooling water is supplied from a cooling water supply device (not shown) and circulates through the cooling pipe 106c. In addition, a second cooling pipe may be arranged inside the support roller 104 and connected to the cooling pipe 106c and the second cooling pipe so that the cooling water also circulates inside the support roller 104. In this way, the mold 105 is cooled by the cooling water passing through the cooling pipe 106c. The cooling water temperature is preferably set to 15°C to 20°C.

The laminated sheet material 11 is conveyed with the surface 11a facing the mold 105 and comes into contact with the rotating mold 105. The vacuum pump sucks air into the inside of the support roller 104 through the support roller 104, intermediate roller 106, and mold 105 in this order. As the air is sucked in, a reduced pressure or vacuum is created between the mold 105 and the surface 11a of the laminated sheet material 11 in contact with the mold 105, so that the surface 11a of the laminated sheet material 11 adheres closely to the outer circumferential surface of the mold 105. As a result, the surface 11a of the laminated sheet material 11, including the softened skin layer 24, is deformed along the unevenness 105a formed on the mold 105, and the uneven shape 12 is formed on the front side of the laminated sheet material 11. The laminated sheet material 11 is conveyed while being vacuum-suctioned by the rotation of the support roller 104. The laminated sheet material 11 is released from the mold 105 by further rotation of the support roller 104.

As described above, in the vacuum suction roll machine 103 in this embodiment, while the laminated sheet material 11 is vacuum-suctioned, cooling water is circulated through the cooling pipe 106c, and the mold 105 is cooled by the cooling water. In other words, the vacuum suction roll machine 103 vacuum-suctions the laminated sheet material 11 while cooling the mold 105. As a result, the laminated sheet material 11 in close contact with the mold 105 is vacuum-suctioned and simultaneously cooled by heat exchange with the mold 105. It is preferable that the laminated sheet material 11 is cooled to 80°C or less.

The vacuum suction roll machine 103 shown in FIG. 10 has a hollow cylindrical molding die 105, and is capable of continuously forming the uneven shape 12 on the long strip of laminated sheet material 11. However, the shape of the molding die 105 is not limited to this, and it may also have a flat molding die, for example. In this case, it is preferable to cut the long strip of laminated sheet material 11 in advance to a size that can be sucked into the flat molding die. Then, the cut laminated sheet material 11 of a predetermined size is intermittently vacuum-formed one by one.

(4) Curing Step (S40, see FIGS. 9 and 11)
In the curing step (S40), the temperature of the laminated sheet material 11 with the uneven shape 12 on the surface 11a, which was raised in the forming step (S30), is lowered to stabilize the uneven shape 12. In the curing step (S40), for example, the laminated sheet material 11 is cooled. More specifically, the laminated sheet material 11 that has been subjected to the forming step (S30) is hung on a plurality of cooling rollers (hardening parts) 107, 107, ... (three in FIG. 9), and cooled while being conveyed in contact with these cooling rollers 107, 107, ... in order. As a result, the laminated sheet material 11 is cured to become the laminated sheet 10.

The cooling rollers 107, 107, ... may be installed along the conveying direction of the laminated sheet material 11 as shown in FIG. 9. The laminated sheet material 11 with the uneven shape 12 is conveyed so that the front surface 11a and the back surface 11b are successively contacted with the multiple cooling rollers 107, 107, ..., so that the front surface 11a and the back surface 11b are successively cooled. The number of cooling rollers 107 installed can be set according to the material constituting the laminated sheet material 11, the temperature setting of the device up to the molding process, etc. Also, 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 may be adjustable according to the state of the laminated sheet material 11 at the time of completion of hardening, etc. For example, if it is determined that the laminated sheet material 11 is not sufficiently hardened by measuring the temperature of the surface of the laminated sheet material 11, the number of cooling rollers 107 that cool the laminated sheet material 11 can be increased to promote hardening. In addition, if it is determined that the laminated sheet material 11 has hardened too much, the number of cooling rollers 107 that cool 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.

As shown in FIG. 11, each cooling roller 107 has a cylindrical support roller 107a, a cooling pipe 107b provided on the outside of 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, and the laminated sheet material 11 on which the uneven shape 12 is formed is pressed against the surface of the cooling pipe 107b. At this time, the surface 11a (the side on which the uneven shape 12 is formed) of the laminated sheet material 11 may face the cooling pipe 107b, or the back surface 11b. However, it is preferable to have the surface 11a of the laminated sheet material 11 facing the cooling pipe 107b, because this promotes cooling of the surface and quickly stabilizes the uneven shape 12. The outer peripheral surface of the cooling pipe 107b may be mirror-finished. Coolant passage 107c is supplied with cooling water from a cooling water supply device (not shown).

In this way, in the cooling roller 107, heat is exchanged between the cooling water and the laminated sheet material 11 via the cooling pipe 107b, and the laminated sheet material 11 is cooled. 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.

In addition, one method of manufacturing a laminated sheet using conventional technology is to simply apply a hot press to the surface 11a of a laminated sheet material 11, which is made by attaching cushioning material 30 to a synthetic resin sheet 20 in advance, to create an uneven shape 12 (hereinafter referred to as the "first conventional manufacturing method"). In the first conventional manufacturing method, as shown in FIG. 12, a mold 110 for hot pressing is pressed against the surface 11a of the softened laminated sheet material 11, to create an uneven shape 12 on the surface 11a, thereby obtaining a laminated sheet 10'.

However, in the manufacturing method according to the first conventional technology, when the mold 110 is pressed, a gap S may be generated between the recess 110 formed in the mold 110 and the laminated sheet material 11, and air may remain. Therefore, the corner K of the protrusion 12a of the uneven shape 12 cannot be in close contact with the mold 110. In that case, the corner K sags, making it difficult to obtain a shape faithful to the shape of the recess 110a of the mold 110. In particular, when the contour of the cross-sectional shape of the recess 110a of the mold 110 has a sharp apex, the surface 11a of the laminated sheet material 11 cannot follow such a contour, and it is difficult for the corner K to obtain a sharp edge along the sharp contour of the recess 110a. In addition, in the manufacturing method according to the first conventional technology, when the size (width, etc.) of the uneven shape 12 is small, for example, when it includes a fine uneven shape such as a fine stitch shape, it is difficult to give the desired uneven shape. Thus, with the manufacturing method according to the first conventional technology, it was difficult to create an uneven shape 12 that faithfully corresponded to the unevenness of the molding die.

In contrast, in the method for manufacturing a laminated sheet according to this embodiment, the laminated sheet material 11 is vacuum-sucked from the front side through a mold. Therefore, even if the unevenness of the mold is small in size or has a complex shape, the mold and the surface 11a of the laminated sheet material 11 can be brought into close contact with each other without any gaps, so that an uneven shape 12 that faithfully corresponds to the mold can be obtained. For example, even if the height of the convex parts 12a included in the uneven shape 12 is high, the contour of the cross-sectional shape of the convex parts 12a has a sharp apex, or the size of the unevenness is minute, the desired uneven shape can be obtained.

As another conventional technique, there is a method (hereinafter referred to as the "manufacturing method according to the second conventional technique") in which a synthetic resin sheet 20 is first formed with a concave-convex shape 12 by vacuum molding, and then a cushioning material 30 having a synthetic resin foam 31 is attached to the back surface of the synthetic resin sheet 20 (the back surface 21b of the base fabric layer 21). In the manufacturing method according to the second conventional technique, it is necessary to attach the synthetic resin sheet 20 with the concave-convex shape 12 to the surface 30a of the flat cushioning material 30, as shown in FIG. 13.

However, when the synthetic resin sheet 20 is placed on the surface 30a of the cushioning material 30, the back side of the convex portion 12a of the uneven shape 12 formed on the synthetic resin sheet 20 becomes hollow, creating a gap S. This means that in order to bond the synthetic resin sheet 20 and the cushioning material 30, it becomes necessary to press the synthetic resin sheet 20 against the cushioning material 30, but this can cause the convex portion 12a to be crushed. For this reason, with the manufacturing method according to the second conventional technology, the uneven shape 12 can end up being flatter than the desired unevenness (the height of the unevenness can be reduced).

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 be deformed simultaneously and integrally to form uneven shapes. Therefore, since the cushion material 30 can deform following the deformation of the synthetic resin sheet 20, it is possible to prevent the synthetic resin sheet 20 from being subjected to pressure in the thickness direction due to the bonding of the cushion material 30, which would damage the uneven shape of the synthetic resin sheet 20. Shapes including tall protrusions can also be formed faithfully to the molding die.

<Production of Laminated Sheet>
[Example 1]
First, a mold used for manufacturing a laminated sheet was prepared by the following method. A mixture of 20 parts by weight of colloidal silica, 80 parts by weight of glass frit, and 5 parts by weight of methyl cellulose was further added with 35 parts by weight of water, and the mixture was kneaded in an extruder to obtain a slurry mixture. This slurry mixture was molded into the shape of the mold and fired to produce a porous ceramic mold. The mold was prepared by faithfully transferring a genuine leather product having a surface irregularity shape as described with reference to Figures 1 to 4 as a prototype (positive) to a silicone resin (negative), and then repeatedly transferring it to epoxy resin, PVC, etc., and then transferring it to a porous ceramic mold (negative).

The prototype of the genuine leather product had a pattern in which the sewing thread was sewn in straight lines at a constant pitch in both the vertical and horizontal directions, with the spaces between the stitching lines raised to form raised sections. The areas on the porous ceramic mold where the sewing thread was transferred had a pitch of 5.0 cm (corresponding to P in Figure 3), the dimension corresponding to the height of the raised sections of the prototype (corresponding to h1 in Figure 3) was 3.0 mm, and the dimension corresponding to the thickness of the sewing thread of the prototype (corresponding to h2 in Figure 3) was 0.4 mm.

On the other hand, a 1 mm thick PVC sheet was prepared as the synthetic resin sheet. A 500 μm thick base fabric (back base fabric layer) was attached to the back side of a 5.0 mm thick urethane foam as the cushioning material. The synthetic resin sheet and the cushioning material were attached by frame lamination. The surface of the PVC sheet was treated with a 20 μm thick polyurethane film. In the frame lamination, the entire area of the urethane foam where the PVC sheet was attached was melted using a burner, and the PVC sheet was attached to obtain a laminated sheet material.

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 as shown in FIG. 9 and FIG. 10 equipped with the above-mentioned forming mold. It was then cooled using a cooling roller as shown in FIG. 9 and FIG. 11. This resulted in a laminated sheet having an uneven surface.

[Examples 2 to 6]
A laminate sheet was produced in the same manner as in Example 1, except that the prototype and the size of the mold were changed (Table 1).

[Comparative Example 1]
A laminate sheet was produced in the same manner as in Example 1, except that the order of the manufacturing steps of the laminate sheet was changed. Specifically, in Comparative Example 1, the same mold as that produced in Example 1 was used, but in the manufacture of the laminate sheet, a PVC sheet (synthetic resin sheet) alone was first molded using the mold, and after the molding, a urethane foam (synthetic resin foam) was attached. In other words, frame lamination was not used.

<Evaluation of the obtained product>
The obtained product (laminate sheet) was evaluated as follows. The evaluation results are shown in Table 1.

(Reproduction of the raised part)
The quilting pattern of the obtained laminated sheet was compared with the original genuine leather product (original product) from which it was taken, and an evaluation was made as to whether the raised parts of the laminated sheet (G12a in FIG. 3, etc.) reproduced the raised parts of the original product. The evaluation criteria were as follows:
⊚: The raised portion is faithfully reproduced. The raised portion has a springy feel and no problems.
◯: The shape of the protuberances is faithfully reproduced, but the protuberances feel somewhat inferior in elasticity to the touch.
△: Partial depressions were observed on the raised portions.
×: Multiple dents are formed on the raised portion.
Here, "the raised portion is faithfully reproduced" means that no depressions at all are observed in the raised portion, just like in the original product.

(Changes in the protruding part over time)
The obtained laminated sheet was stored at 100° C. for 100 hours, and then the change in state compared with the state before storage was evaluated. The evaluation criteria were as follows:
◎: No change in appearance or texture.
○: No change in appearance, but a difference in feel (stress felt when pressed is weaker than the sample before storage).
△: Slight dents are observed.
x: Multiple dents are formed.

(Reproduction of the stitches in the cleavage)
The quilting pattern of the obtained laminated sheet was compared with the original genuine leather product (original product) from which it was taken, and an evaluation was made as to whether the fine unevenness (M12 in Fig. 1, etc.) present in the valleys (grooves, G12b in Fig. 1, etc.) between the raised parts reproduced the stitching of the sewing thread of the original product (whether it looked like the sewing thread). The specific evaluation criteria were as follows:
◎: Even when observed with the naked eye or under a 30x loupe, the twist of the sewing thread is clearly reproduced. ○: There is no difference from ◎ to the naked eye, but when magnified with a 30x loupe, some of the twist of the sewing thread is missing.
△: When observed with the naked eye, some of the twists in the sewing thread are missing.
x: When observed with the naked eye, defects such as unevenness in the thickness of the sewing thread are evident, or when observed with the naked eye, the sewing thread is missing twists in multiple places.

As shown in Table 1, in the examples (Examples 1 to 6) where unevenness was formed by vacuum suction on a laminated sheet material obtained by attaching a synthetic resin foam to the back side of a synthetic resin sheet, the shape of the molding die was faithfully reproduced, and the condition of the raised portion after a specified time had passed was also good. In all of the laminated sheets of Examples 1 to 7, unevenness was observed on the back side as well, and the overall shape was warped toward the front side.

Specific aspects of the present invention are described below along with their effects.

The first aspect is a method for manufacturing a laminated sheet that includes a synthetic resin sheet and a cushioning material laminated from the front side to the back side, and has irregularities at least on the front side, and includes a preparation step of attaching the cushioning material to the back side of the synthetic resin sheet to prepare 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 material to impart irregularities.

According to the first aspect, after the cushioning material is attached to the synthetic resin sheet in advance to obtain a laminated sheet material, the surface is given an uneven shape. Therefore, when the synthetic resin sheet is deformed during vacuum suction, the cushioning material follows the deformation, and the cushioning material adheres to the back side of the raised convex parts, so that the cushioning material can be sufficiently filled. Therefore, the desired three-dimensional effect of the convex parts is not lost, and a clear uneven shape can be formed. More specifically, in the final product (laminate sheet) obtained, the cushioning material is evenly adhered to and filled all over the back side of the raised parts, especially those with large uneven shapes, and a plump finish is obtained. In addition, by bonding the synthetic resin sheet and the cushioning material together in advance before the uneven shape is given, that is, in a flat state, it is possible to bond them together without any gaps, and the bonding strength between the two is increased, so that the durability of the obtained laminated sheet is high and the plump appearance and elasticity can be continuously maintained.

In addition, according to this embodiment, vacuum forming is used to provide the uneven shape in the molding process. Therefore, the uneven shape can be provided while the surface of the laminated sheet material is in good contact with the mold without any gaps. As a result, even if the unevenness of the mold is complex or the size of the unevenness on the surface of the mold is small, it is possible to obtain an uneven shape that faithfully corresponds to the mold or faithfully reproduces the uneven shape of the original product from which the mold was taken. For example, even if an uneven shape with sharp edges between the concave and convex parts is desired in cross section, it is possible to provide a shape that is faithful to the desired shape. In addition, it is possible to faithfully provide high convex parts and fine uneven shapes. In addition, since the mold is made of a porous material, air can be sucked in almost evenly from the entire outer peripheral surface of the mold. Therefore, the laminated sheet material can be more evenly adhered to the mold, and the cushion material can deform in accordance with the deformation of the synthetic resin sheet to form an uneven pattern that faithfully reflects the unevenness of the mold.

Furthermore, according to this embodiment, it is possible to prevent stress from occurring at the bonding position of the synthetic resin sheet and the cushioning material during molding, which would damage the bonded portion, or stress from concentrating on one part of the cushioning material, which would destroy the air bubbles inside. If the laminated sheet is damaged, deterioration over time will be accelerated from that point, but this embodiment suppresses the generation of such damage, so that changes over time (deterioration) are reduced even when used for a longer period of time than conventional products. In addition, changes over time (deterioration) can be delayed even when stored at temperatures higher than room temperature.

In the second embodiment, the preparation step is carried out by frame lamination.

According to the second aspect, the synthetic resin sheet and the cushioning material can be attached without using adhesive. This makes it possible to prevent the adhesive surfaces (the back surface of the synthetic resin sheet and the surface of the cushioning material) from becoming hard, and the laminated sheet material, and in turn the laminated sheet, which is the final product, from becoming hard. In addition, it is possible to prevent the laminated sheet from being unable to deform as desired in the molding process (unevenness imparting process) due to the presence of a hard adhesive layer in the laminated sheet. For example, when it is desired to impart a complex, particularly fine uneven shape, if there is a hardened adhesive layer, ruptures may occur in or near that layer, and the cushioning material may be unable to follow the deformation of the synthetic resin sheet. However, according to this aspect, such a situation can be prevented.

In a third aspect, the synthetic resin sheet is a synthetic leather that includes a surface layer containing polyvinyl chloride and a surface treatment layer formed on the surface side of the surface layer.

According to the third aspect, the surface of the laminated sheet material can be made harder than when, for example, the synthetic resin sheet is synthetic leather containing polyurethane in the skin layer. As a result, when forming the uneven shape in the molding process, it is possible to more reliably form uneven shapes with sharp edges and form clear uneven shapes than when the synthetic resin sheet is synthetic leather containing polyurethane in the skin layer. Furthermore, even with a synthetic resin sheet made of such a relatively hard material, the synthetic resin sheet can adhere to the mold in this aspect, so that the uneven shape can be more reliably formed on the surface of the laminated sheet material.

In a fourth aspect, the synthetic resin sheet further includes a base fabric layer on the back side of the skin layer.

According to the fourth aspect, the strength and shape stability of the synthetic resin sheet can be increased. The synthetic resin sheet having a base fabric layer is suitable for use in applications where it is necessary to continuously receive force, for example, as a covering material for vehicle seats (car seats).

In the fifth embodiment, the molding step is carried out while the mold is cooled.

According to the fifth aspect, the temperature of the surface of the laminated sheet material can be reduced during the molding process. This prevents the uneven shape from sagging, and even if the desired uneven shape includes sharp edges, it is possible to obtain an uneven shape that more reliably reflects the shape of the molding die.

In a sixth aspect, the softening step includes increasing the heating temperature of the laminated sheet material in a stepwise or gradual manner.

According to the sixth aspect, the temperature of the laminated sheet material can be gradually increased as it is conveyed, thereby preventing uneven heating. This prevents partial softening of the synthetic resin sheet, prevents wrinkles from appearing on the surface, and allows the entire laminated sheet material to be softened evenly while maintaining a smooth surface.

In the seventh aspect, the mold is made of porous ceramic.

Ceramics are materials with high heat resistance and hardness compared to other materials such as metals and resins. Therefore, according to the seventh embodiment, even if the mold becomes hot, thermal expansion is unlikely to occur, the shape is highly stable, and it is unlikely to deform due to impact. In addition, by using ceramics as the material for the mold, it is easy to form fine pores throughout the material, making it easy to obtain uniform breathability throughout the mold.

In an eighth aspect, the cushioning material includes a synthetic resin foam containing polyurethane.

According to the eighth aspect, when the laminated sheet material is vacuum-suctioned, the cushioning material can be smoothly deformed in accordance with the deformation of the synthetic resin sheet. Therefore, the cushioning material can adequately support the back side of the protrusion.

Furthermore, because the cushioning material has a polyurethane foam resin body on the front side, the surface can be easily melted during the frame lamination process in the preparation process. In addition, even after the synthetic resin sheet and the cushioning material are bonded together, the elasticity of the interface between the two can be maintained. This allows for flexible deformation to fit the molding die during the molding process, and the unevenness of the molding die can be faithfully reflected on the surface of the laminated sheet, even if the shape is complex and uneven.

In a ninth aspect, the unevenness on the front side of the laminated sheet includes raised portions that rise on the front side, grooves between the raised portions, unevenness, and linear fine unevenness that extends along the bottom of the grooves.

According to the ninth aspect, it is possible to realize a more aesthetically pleasing design, for example a pattern that imitates quilting.

In a tenth embodiment, the back side of the laminate sheet also has irregularities, and the irregularities on the back side include depressions from the back side to the front side at positions corresponding to the raised portions.

According to the tenth aspect, it is possible to form large raised portions that cannot be obtained by other press molding methods, and a laminated sheet is obtained that fully maintains its elasticity. In addition, the shape stability of the raised portions over time is also high.

In an eleventh embodiment, the height of the raised portion is 3 mm or more and 8 mm or less.

According to the eleventh aspect, the laminate sheet produced has plump raised portions that are suitable for use as a skin material for interior parts, resulting in a more aesthetically pleasing design.

In a twelfth embodiment, the height of the convex portions included in the fine irregularities is 0.4 mm or more and 1.2 mm or less.

According to the twelfth aspect, the laminated sheet produced has a design that reproduces a more aesthetically pleasing stitch pattern in a pattern that mimics quilting.

The thirteenth aspect is a manufacturing device for a laminated sheet that includes a synthetic resin sheet and a cushioning material laminated from the front side to the back side, and has irregularities at least on the front side, and includes 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 forming unit that applies irregularities by vacuum suction from the front side of the laminated sheet material through a forming die made of a porous member.

According to the thirteenth aspect, the same effect as that obtained by the aspect according to supplementary note 1 can be obtained.

Specific aspects of the present invention will be described below, along with their effects.

[1] A preparation step of forming a laminated sheet material by attaching a cushioning material having a synthetic resin foam to a back surface of a base fabric layer of a synthetic resin sheet having a surface layer made of a synthetic resin on the front surface of the base fabric layer by frame lamination processing;
a softening step of heating the laminated sheet material to soften the laminated sheet material including at least the skin layer;
a forming step of vacuum-suctioning the surface of the laminated sheet material including the skin layer through a breathable mold to form an uneven shape on the surface of the laminated sheet material;
and a hardening step of cooling and hardening the laminated sheet material having the concave and convex shape formed thereon.

[2] In the method for producing a laminate sheet according to the above item [1],
The method for producing a laminate sheet, wherein the synthetic resin sheet is synthetic leather containing polyvinyl chloride in the surface layer.

[3] In the method for producing a laminate sheet according to the above item [1] or [2],
A method for manufacturing a laminated sheet, wherein in the molding step, the laminated sheet material is vacuum-suctioned while the mold is cooled.

[4] In the method for producing a laminate sheet according to the above item [1] or [2],
A method for manufacturing a laminated sheet, characterized in that in the softening step, the temperature to which the laminated sheet material is heated is set to gradually increase along a conveying direction of the laminated sheet material.

[5] The method for producing a laminated sheet according to the above item [1] or [2], wherein the molding die is made of porous ceramic.

[6] In the method for producing a laminate sheet according to the above item [1] or [2],
2. A method for producing a laminate sheet, wherein the synthetic resin foam of the cushioning material contains polyurethane.

According to one aspect of the present invention, the laminated sheet 10 is manufactured by sequentially going through a preparation process, a softening process, a molding process, and a curing process. Here, the preparation process is a process of attaching a cushioning material 30 to a synthetic resin sheet 20 by frame lamination processing to produce a laminated sheet material 11. The softening process is a process of softening the surface 11a of the laminated sheet material 11 including the skin layer 24. The molding process is a process of applying a vacuum to the surface 11a of the laminated sheet material 11 including the softened skin layer 24, thereby forming an uneven shape 12 on the surface 11a of the laminated sheet material 11. The curing process is a process of cooling and curing the laminated sheet 10 with the uneven shape 12 formed on the surface 11a.

In the manufacturing method of the laminated sheet 10 according to the above embodiment, the laminated sheet material 11, in which the cushioning material 30 has been attached to the synthetic resin sheet 20 in advance, is vacuum-suctioned through the mold 105, and the uneven shape 12 is attached to the surface 11a of the laminated sheet material 11. Therefore, the cushioning material 30 is already filled on the back side of the protrusions 12a that are attached to the surface 11a by vacuum suction (vacuum forming). As a result, the protrusions 12a that protrude due to the deformation of the synthetic resin sheet 20 during vacuum suction are supported by the cushioning material 30. As a result, the manufacturing method of the laminated sheet 10 according to the above embodiment can form a clear uneven shape 12 without compromising the three-dimensional effect of the protrusions 12a.

In addition, in the manufacturing method of the laminated sheet 10 according to the above embodiment, the uneven shape 12 is formed on the laminated sheet material 11 by vacuum suction (vacuum forming). In other words, the uneven shape 12 is formed on the laminated sheet material 11 by closely contacting the surface 11a of the laminated sheet material 11 with the molding die 105. As a result, the manufacturing method of the laminated sheet 10 of the first embodiment can make the boundary between the recessed portion 12b and the protruding portion 12a a sharp edge, and can suppress the crushing of the uneven shape 12. As a result, the fine uneven shape 12 can be formed on the surface 11a of the laminated sheet material 11 in which the cushion material 30 having the synthetic resin foam 31 is attached to the back surface of the synthetic resin sheet 20.

In addition, in the manufacturing method of the laminated sheet 10 according to the above aspect, in the preparation step, the cushion material 30 is attached to the back surface of the synthetic resin sheet 20 by frame lamination processing. Therefore, in the manufacturing method of the laminated sheet 10 according to this embodiment, the synthetic resin sheet 20 and the cushion material 30 can be attached without using an adhesive, and the laminated sheet material 11 can be prevented from hardening.

In addition, in the manufacturing method of the laminated sheet 10 according to the above embodiment, the synthetic resin sheet 20 is synthetic leather containing polyvinyl chloride in the skin layer 24. Therefore, the surface 11a 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 the uneven shape 12 is formed in the molding process, the edges of the uneven shape 12 can be made sharper and a clearer uneven shape 12 can be formed than when the synthetic resin sheet 20 is synthetic leather containing polyurethane in the skin layer 24.

In addition, in the manufacturing method of the laminated sheet 10 according to one aspect of the present invention, in the molding process, the surface 11a of the laminated sheet material 11 is vacuum-suctioned while the mold 105 is cooled. Therefore, the surface 11a of the laminated sheet material 11 is deformed by vacuum suction and is simultaneously cooled through the mold 105. This makes it possible to promote a decrease in the temperature of the surface 11a of the laminated sheet material 11 while forming the uneven shape 12. This also suppresses sagging of the uneven shape 12, and makes it possible for the laminated sheet 10 to obtain an uneven shape 12 with sharp edges.

In addition, in the manufacturing method of the laminated sheet 10 according to one aspect of the present invention, in the softening process, the temperature to which the laminated sheet material 11 is heated is set to gradually increase along the conveying direction of the laminated sheet material 11. As a result, the temperature of the laminated sheet material 11 gradually increases as it is conveyed, thereby preventing uneven heating. This makes it possible to prevent partial softening of the synthetic resin sheet 20, prevent wrinkles from appearing on the surface 11a, and soften the entire laminated sheet material 11 evenly while maintaining the smooth surface 11a.

In addition, in the manufacturing method of the laminated sheet 10 according to one aspect of the present invention, the mold 105 used in the molding process is made of porous ceramic. This allows air to be sucked in almost evenly from the entire outer peripheral surface of the mold 105 during the molding process. As a result, the laminated sheet material 11 can be evenly attached to the mold 105, and the uneven shape 12 formed on the surface 11a of the laminated sheet material 11 can have sharp edges.

Furthermore, in the manufacturing method of the laminated sheet 10 according to one aspect of the present invention, the synthetic resin foam 31 of the cushioning material 30 contains polyurethane. Therefore, when the laminated sheet material 11 of Example 1 is vacuum-suctioned, the cushioning material 30 can be smoothly deformed in accordance with the deformation of the synthetic resin sheet 20. Therefore, the cushioning material 30 can adequately support the back side of the convex portion 12a, and the concave-convex shape 12 with sharp edges can be formed on the surface 11a of the laminated sheet material 11.

In one embodiment of the method for manufacturing a laminated sheet 10 according to the present invention, a vacuum suction roll machine 103 used in the forming process has a hollow cylindrical forming die 105, and is capable of forming a continuous uneven shape 12 on a strip-shaped laminated sheet material 11. However, the shape of the forming die 105 is not limited to this. For example, a vacuum suction machine having a flat forming die may be used to form the uneven shape 12 on the laminated sheet material 11.

When using a vacuum suction machine with a flat mold, the strip-shaped laminated sheet material 11 is cut in advance to a size that can be sucked into the flat mold. Then, the cut laminated sheet material 11 of a predetermined size is intermittently vacuum-formed one piece at a time.

In addition, in the laminate sheet 10 manufactured according to one embodiment of the present invention, the synthetic resin foam 31 of the cushion material 30 contains polyurethane. Here, the synthetic resin foam 31 containing polyurethane generally has an easily adjustable hardness. Therefore, it is possible to appropriately adjust the hardness of the cushion material 30 according to the material and hardness of the synthetic resin sheet 20, the application and specification requirements of the laminate sheet 10, and the like, to produce a laminate sheet material 11 that is easy to form a fine uneven shape 12 on the surface 11a.

However, the material of the synthetic resin foam 31 of the cushioning material 30 is not limited to one containing polyurethane and can be selected arbitrarily.

In addition, the laminated sheet 10 manufactured according to one embodiment of the present invention has a synthetic resin sheet 20, a base fabric layer 21, and a skin layer 24, in which an adhesive layer and an intermediate layer 23 made of synthetic resin foam are laminated in this order from the base fabric layer 21 side toward the skin layer 24. Therefore, the texture, feel, etc. can be easily set to a desired state by adjusting the material of the intermediate layer 23.

However, when the laminated sheet material 11 is vacuum-suctioned, the air bubbles contained in the intermediate layer 23 may expand and become larger in the thickness direction of the laminated sheet material 11, which may reduce the abrasion resistance of the laminated sheet 10. For this reason, a synthetic resin sheet 20 without an intermediate layer 23 may be used, or the abrasion resistance of the surface treatment layer 25 (if the surface treatment layer 25 is two layers, the first surface treatment layer on the front side and/or the second surface treatment layer on the back side) may be increased.

The synthetic resin sheet 20 of the laminate sheet 10 manufactured according to the embodiment is synthetic leather containing polyvinyl chloride in the skin layer 24. However, the material of the synthetic resin sheet 20 is not limited to this. The synthetic resin sheet 20 may be, for example, synthetic leather containing polyurethane in the skin layer 24 depending on the application, required durability, cost, etc. of the laminate sheet 10. Furthermore, the synthetic resin sheet 20 may be artificial leather using a nonwoven fabric for the base fabric layer 21.

In addition, in the manufacturing method of the laminated sheet 10 according to the embodiment, the vacuum suction roll machine 103 used in the molding process has a molding die 105 made of porous ceramic. However, the molding die 105 is not limited to being made of porous ceramic as long as it has breathability and can vacuum-suck the laminated sheet material 11. In other words, in the molding process, for example, a molding die made of metal such as aluminum with appropriate degassing holes may be used.

The present invention has been described above based on specific embodiments and examples, but these embodiments and examples are presented merely 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.

10 Laminated sheet 11 Laminated sheet material 11a Surface 11b of laminated sheet material Back surface 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 100 Frame laminator (preparation section)
102 heater (softening section)
103 Vacuum roll machine (molding section)
105 Mold 107 Cooling roller (hardening part)
G12 Large uneven shape G12a Protuberance G12b Groove M12 Fine uneven shape M12a Convex part of the fine uneven shape M12b Concave part of the fine uneven shape

Claims (13)

A method for producing a laminated sheet including a synthetic resin sheet and a cushioning material laminated in this order from a front side to a back side, 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 prepare a laminated sheet material;
a softening step of softening the laminated sheet material;
and a molding step of providing irregularities by vacuum suction from the front side of the laminated sheet material through a molding die made of a porous material. The method for manufacturing a laminated sheet according to claim 1, wherein the preparation step is carried out by frame lamination. The method for manufacturing a laminated sheet according to claim 1 or 2, 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. The method for manufacturing a laminated sheet according to claim 3, wherein the synthetic resin sheet further comprises a base fabric layer on the back side of the skin layer. The method for producing a laminated sheet according to claim 1 or 2, wherein the molding step is carried out while the mold is cooled. The method for manufacturing a laminate sheet according to claim 1 or 2, wherein the softening step includes stepwise or gradually increasing the heating temperature of the laminate sheet material. The method for manufacturing a laminated sheet according to claim 1 or 2, wherein the mold is made of porous ceramic. The method for manufacturing a laminated sheet according to claim 1 or 2, wherein the cushioning material includes a synthetic resin foam containing polyurethane. The unevenness on the front side of the laminated sheet includes:
An uneven surface having raised portions on the front side and grooves between the raised portions;
The method for producing a laminated sheet according to claim 1 or 2, wherein a bottom of the groove includes linear fine projections and recesses extending along the groove. The back side of the laminated sheet also has irregularities,
The method for producing a laminated sheet according to claim 9 , wherein the unevenness on the back side includes depressions from the back side to the front side at positions corresponding to the protrusions. The method for manufacturing a laminated sheet according to claim 9, wherein the height of the raised portion is 3 mm or more and 8 mm or less. The method for manufacturing a laminated sheet according to claim 9, wherein the height of the convex portions included in the fine irregularities is 0.4 mm or more and 1.2 mm or less. A manufacturing apparatus for a laminated sheet including a synthetic resin sheet and a cushioning material laminated in this order from a front side to a back side, and having irregularities on at least the front side, comprising:
a preparation unit for preparing a laminated sheet material by attaching a front side of a cushioning material to a back side of a synthetic resin sheet;
a softening section for heating and softening the laminated sheet material;
and a molding section that applies a vacuum to the front side of the laminated sheet material through a molding die made of a porous material to impart irregularities thereto.