JP7634374B2 - Synthetic resin skin material and method for producing same - Google Patents

Description

This disclosure relates to a synthetic resin skin material and a method for manufacturing a synthetic resin skin material.

TECHNICAL FIELD Synthetic resin skin materials (which may be simply referred to as "skin materials" in this disclosure) that are highly durable are often used in place of natural leather or fiber sheets for automobile interior parts such as instrument panels, door trims, seats, and ceilings, railway car and aircraft interior parts such as trims, seats, and ceilings, furniture, shoes, footwear, bags, interior and exterior components for building decoration, clothing covering materials and linings, wall covering materials, and the like.
As a synthetic resin skin material, for example, Patent Document 1 discloses a synthetic leather in which a substrate is pretreated to have a peel strength of 10 g/cm to 300 g/cm, a wet silver layer is formed on the upper surface of the substrate by a normal method, and after post-processing, the substrate is peeled off to produce a wet silver layer product. The surface of the wet silver layer product from which the substrate has been peeled off is then coated with an adhesive or a base fabric is coated with an adhesive, and the base fabric is bonded to the surface.
Such synthetic leather (synthetic resin skin material) generally has an uneven surface, i.e., a grain pattern, similar to that of natural leather, on the outermost surface, and this grain pattern is a major defining feature of the appearance.

Japanese Patent Application Publication No. 9-031859

When dirt adheres to the surface of a synthetic resin skin material, it can be difficult to completely wipe off the dirt depending on the uneven shape of the surface.
Furthermore, today's society has become more diverse in its values, and there is a demand for the development of skin materials with new appearances that are different from conventional ones.

In view of the above circumstances, the present disclosure aims to provide a synthetic resin skin material that is easy to wipe off and has a design that has an appearance different from that of conventional skin materials, and a method for manufacturing the same.

The means for solving the problem include the following embodiments.
<1> A synthetic resin skin material including a skin layer containing a synthetic resin, wherein an uneven pattern is formed on the surface of the synthetic resin skin material, and the uneven shape of the surface in a cross section including a point where the thickness of the unevenness of the surface is greatest and a point where the thickness is smallest satisfies all of the following conditions (1) to (3):
(1) The convex portion has an apex and an inclined portion inclined from the apex toward the bottom of the adjacent concave portion, and is in contact with the apex. Of the two angles formed by the intersection of a line perpendicular to the thickness direction of the skin material and a line along the inclined portion, the angle on the side including the convex portion is 160° to 178°.
(2) The opening length of the recess in a direction perpendicular to the thickness direction of the skin is 2 mm to 13 mm.
(3) The depth of the recess is 0.1 mm to 0.4 mm.
<2> The synthetic resin skin material according to <1>, wherein the projections and recesses are repeatedly arranged in a constant pattern in at least one of the length direction and the width direction of the synthetic resin skin material.
<3> The synthetic resin skin material according to <2>, wherein the projections and recesses are repeatedly arranged in a constant pattern in both the length direction and the width direction of the synthetic resin skin material.
<4> The synthetic resin skin material according to any one of <1> to <3>, wherein the projections and recesses are arranged so as to present a geometric pattern over the entire surface of the synthetic resin skin material.
<5> The synthetic resin skin material according to any one of <1> to <4>, wherein the three-dimensional surface roughness of the surface having the irregularities of the synthetic resin skin material is 1.637 μm or less.
<6> A method for producing the synthetic resin skin material according to any one of <1> to <5>, comprising the steps of: preparing a synthetic resin sheet including a synthetic resin layer for forming the skin layer;
a step of embossing the synthetic resin layer using an embossing roll or an embossing plate to form a concave-convex pattern that satisfies all of the above conditions (1) to (3) on the surface of the synthetic resin sheet;
A method for producing a synthetic resin skin material, comprising:

This disclosure makes it possible to provide a synthetic resin skin material and a manufacturing method thereof that has excellent dirt-removal properties and exhibits design potential with an appearance that is different from that of conventional skin materials.

FIG. 1 shows an example (Example 1) of a synthetic resin skin material according to the present disclosure, in which (A) a surface on which irregularities are formed, (B) a cross-sectional shape at a measurement position, and (C) a cross-sectional shape in which the depth (thickness) of the cross-sectional shape is enlarged by 10 times. 1A is a diagram showing a surface on which projections and recesses are formed, FIG. 1B is a cross-sectional shape at a measurement position, and FIG. 1C is a cross-sectional shape in which the depth (thickness) of the cross-sectional shape is enlarged tenfold for one example (Example 3) of a synthetic resin skin material according to the present disclosure. 1A is a diagram showing a surface on which projections and recesses are formed, (B) a cross-sectional shape at a measurement position, and (C) a cross-sectional shape in which the depth (thickness) of the cross-sectional shape is enlarged tenfold for one example (Example 5) of a synthetic resin skin material according to the present disclosure. FIG. 1A and 1B are diagrams showing a surface on which projections and recesses are formed, a cross-sectional shape at a measurement position, and a cross-sectional shape in which the depth (thickness) of the cross-sectional shape is enlarged tenfold for one example (Example 7) of a synthetic resin skin material according to the present disclosure. 1A is a diagram showing a surface on which projections and recesses are formed, (B) a cross-sectional shape at a measurement position, and (C) a cross-sectional shape in which the depth (thickness) of the cross-sectional shape is enlarged tenfold for one example (Example 9) of a synthetic resin skin material according to the present disclosure. FIG. 1A is a diagram showing a surface on which projections and recesses are formed, (B) a cross-sectional shape at a measurement position, and (C) a cross-sectional shape in which the depth (thickness) of the cross-sectional shape is enlarged tenfold for an example (Example 11) of a synthetic resin skin material according to the present disclosure. FIG. 1A is a diagram showing a surface on which projections and recesses are formed, (B) a cross-sectional shape at a measurement position, and (C) a cross-sectional shape in which the depth (thickness) of the cross-sectional shape is enlarged tenfold for one example (Example 13) of a synthetic resin skin material according to the present disclosure. FIG. 1A and 1B are diagrams showing a surface on which projections and recesses are formed, a cross-sectional shape at a measurement position, and a cross-sectional shape in which the depth (thickness) of the cross-sectional shape is enlarged tenfold for an example (Example 15) of a synthetic resin skin material according to the present disclosure. 1A is a diagram showing a surface on which projections and recesses are formed, (B) a cross-sectional shape at a measurement position, and (C) a cross-sectional shape in which the depth (thickness) of the cross-sectional shape is enlarged tenfold for one example (Example 17) of a synthetic resin skin material according to the present disclosure. FIG. 1A and 1B are diagrams showing a surface on which projections and recesses are formed, a cross-sectional shape at a measurement position, and a cross-sectional shape in which the depth (thickness) of the cross-sectional shape is enlarged tenfold for one example (Example 19) of a synthetic resin skin material according to the present disclosure. 1A and 1B are diagrams showing a surface on which projections and recesses are formed, a cross-sectional shape at a measurement position, and a cross-sectional shape in which the depth (thickness) of the cross-sectional shape is enlarged tenfold for an example of a conventional synthetic resin skin material (Comparative Example 1). 1 shows an example of the uneven shape of the surface in a cross section where the unevenness difference is maximum for a synthetic resin skin material according to the present disclosure. 1 shows an example of the uneven shape in a cross section where the unevenness difference is maximum in a synthetic resin skin material according to the present disclosure. 1 shows an example of a convex shape in a cross section where the difference in unevenness between convex and concave portions is maximum in a synthetic resin skin material according to the present disclosure. 1 shows an example of a convex shape in a cross section where the difference in unevenness between convex and concave portions is maximum in a synthetic resin skin material according to the present disclosure. 1 shows an example of a convex shape in a cross section where the difference in unevenness between convex and concave portions is maximum in a synthetic resin skin material according to the present disclosure. 1 shows an example of the uneven shape in a cross section where the unevenness difference is maximum in a synthetic resin skin material according to the present disclosure. 1 shows an example of the uneven shape in a cross section where the unevenness difference is maximum in a synthetic resin skin material according to the present disclosure. 1 shows an example of a layer structure of a synthetic resin skin material according to the present disclosure. 1 shows an example of a layer structure of a synthetic resin skin material according to the present disclosure.

The synthetic resin skin material and the method for producing the same according to the present disclosure will be described in detail below.
The description of the components described below may be based on representative embodiments of the present disclosure, but the present disclosure is not limited to the following embodiments.
In the present disclosure, the use of "to" indicating a range of values means that the values before and after the range are included as the lower limit and upper limit.
In the numerical ranges described in stages in this disclosure, an upper limit value described in one numerical range may be replaced by an upper limit value of another numerical range described in stages, or a lower limit value described in one numerical range may be replaced by a lower limit value of another numerical range described in stages.
In addition, in the numerical ranges described in the present disclosure, the upper or lower limit of the numerical ranges may be replaced with values shown in the examples.
In this disclosure, combinations of preferred aspects are more preferred aspects.
In the present disclosure, the term "step" refers not only to an independent step, but also to a step that cannot be clearly distinguished from other steps, as long as the intended purpose of the step is achieved.
In this disclosure, polyvinyl chloride resin may be referred to as PVC.

The inventors of this disclosure have found that when unevenness is formed on the surface of a skin material to form a pattern using the unevenness, it is possible to present an appearance that is different from that of conventional skin materials, but when dirt adhering to the surface is wiped off with a cloth, the uneven shape may make the dirt difficult to remove or easy to remove. As a result of carefully examining the shape of the convex parts, the size of the concave parts, the uneven pattern, etc., it has been found that the inclination angle of the convex parts in a cross section including the points where the thickness of the surface unevenness is greatest and the points where it is smallest, the opening length of the concave parts, and the depth of the concave parts have a significant effect on the ease of removing dirt, and that when the uneven shape meets certain conditions, dirt adhering to the surface can be easily removed by wiping, and the material presents an appearance that is different from that of conventional skin materials and exhibits design properties.

<Synthetic resin skin material>
The synthetic resin skin material according to the present disclosure includes a skin layer containing a synthetic resin, and has an uneven pattern formed on the surface of the skin material, and the uneven shape of the surface in a cross section including a point where the unevenness of the surface on which the uneven pattern is formed is greatest and a point where the unevenness is smallest (sometimes referred to as a "cross section with a maximum unevenness difference" in the present disclosure) satisfies all of the following conditions (1) to (3):
(1) The convex portion has an apex and an inclined portion inclined from the apex toward the bottom of the adjacent concave portion, and is in contact with the apex. Of the two angles formed by the intersection of a line perpendicular to the thickness direction of the skin material and a line along the inclined portion, the angle on the side including the convex portion (sometimes referred to in this disclosure as the "inclination angle of the convex portion") is 160° to 178°.
(2) The opening length of the recess in a direction perpendicular to the thickness direction of the skin material (sometimes referred to as the "opening length of the recess" in this disclosure) is 2 mm to 13 mm.
(3) The depth of the recess is 0.1 mm to 0.4 mm.
When the projections and recesses formed on the surface of the skin material satisfy all of the above conditions (1) to (3), the material has excellent wipe-off properties and exhibits a design that provides an appearance different from that of conventional skin materials.
The skin material according to the present disclosure will be specifically described below with reference to the attached drawings. For the sake of convenience, the shapes, dimensions, angles, and the like in the drawings are exaggerated as appropriate. The direction perpendicular to the thickness direction of the skin material may be referred to as the "horizontal direction."

Figure 12 shows an example of the uneven surface shape in a cross section where the unevenness difference of the synthetic resin skin material according to the present disclosure is maximum. As shown in Figure 12, mountain-shaped convex portions 12 are formed at regular intervals along the horizontal direction (direction D) on the surface of the skin material 10. Each convex portion 12 has a shape that is symmetrical with respect to a straight line P in the thickness direction (direction perpendicular to direction D) that passes through the apex, and the uneven shape satisfies the following conditions (1) to (3).

(1) Of the two angles α and β formed by the intersection of a horizontal line H that contacts the top of the convex portion 12 and a line L that follows the inclined portion of the convex portion 12, the angle α on the side that includes the convex portion 12 is in the range of 160° to 178°. When the angle α is 160° or more, the angle of the inclined portion of the convex portion 12 is gentle, and even if dirt gets into the concave portion 14, it is easy to remove. On the other hand, when the angle α is 178° or less, the design of the uneven pattern can be exhibited when the surface of the skin material 10 is viewed in a plane. From this perspective, it is preferable that the angle α is 165° to 175°.

(2) The opening length X of the recess 14 is in the range of 2 mm to 13 mm. In the present disclosure, the opening length X of the recess 14 means the horizontal distance between the tops of the two protrusions 12 adjacent to the recess 14. In FIG. 12, the height (thickness) of the tops of the two protrusions 12 adjacent to the recess 14 is the same, but even if the heights of the tops of the protrusions on both sides of the recess are different, the horizontal distance between the tops is the opening length X of the recess. When the opening length X of the recess 14 is 2 mm or more, even if dirt gets into the recess 14, it is difficult to clog and is easy to remove. On the other hand, when the opening length X of the recess 14 is 13 mm or less, the design of the uneven pattern can be exhibited when the surface of the skin material 10 is viewed in a plane. From this perspective, it is preferable that the opening length X of the recess 14 is 3 mm to 10 mm.

(3) The depth Y of the recess 14 is in the range of 0.1 mm to 0.4 mm. The depth Y of the recess 14 means the distance in the thickness direction from the tops of the two protrusions 12 adjacent to the recess 14 to the bottom of the recess 14. In FIG. 12, the height (thickness) of the tops of the two protrusions 12 adjacent to the recess 14 is the same, but when the heights of the tops of the protrusions on both sides of the recess are different, the depth Y of the recess is the distance in the thickness direction from the top of the higher (thicker) to the bottom of the recess. When the depth Y of the recess 14 is 0.1 mm or more, the design of the uneven pattern can be exhibited when the surface of the skin material 10 is viewed in a plane. On the other hand, when the depth Y of the recess 14 is 0.4 mm or less, even if dirt enters the recess 14, it is difficult to clog and is easy to remove. From this viewpoint, the depth Y of the recess 14 is preferably 0.2 mm to 0.3 mm.

The measurement points for the unevenness of the surface of the skin material 10 are the points between the two points with the greatest unevenness difference (the points where the thickness of the unevenness of the surface is greatest and the points where it is smallest) in a plan view, with a straight line drawn over the shortest distance. In other words, the unevenness between the two points with the greatest unevenness difference is measured. Specifically, the measurement can be performed using a 3D scanner.

The uneven pattern on the surface of the skin material according to the present disclosure is not particularly limited, but it is preferable that the unevenness is repeatedly arranged in a fixed pattern in at least one of the length direction and width direction of the skin material, and the unevenness may be repeatedly arranged in a fixed pattern in both the length direction and width direction. By arranging the unevenness pattern in one or both of the length direction and width direction of the skin material, a regular design can be presented by the unevenness pattern, and design can be improved. Note that the "uneven pattern" in the present disclosure is not limited to the case where unevenness is formed regularly in one or both of the length direction and width direction of the skin material, but means an arrangement of unevenness that presents a design pattern by the unevenness.

In addition, the surface of the skin material according to the present disclosure may satisfy the above-mentioned conditions (1) to (3) not only in the cross section where the difference in unevenness is greatest, but also in cross sections in other directions within the plane. By forming an uneven pattern in which the uneven shape in the cross section satisfies conditions (1) to (3) over the entire surface of the synthetic resin skin material, the ease of wiping off dirt can be further improved.

The unevenness on the surface of the skin material is preferably arranged so as to present a geometric pattern over the entire surface when viewed in a plane. The geometric pattern formed by the unevenness on the surface of the skin material may be a pattern created by continuously expanding a combination arrangement of components such as polygons (e.g., triangles, quadrangles, hexagons), circles, ellipses, and straight lines, while performing operations such as translation, inversion, rotation, enlargement, reduction, and division, or a pattern generated by a geometric curve that can be expressed by a periodic function.

Examples of the uneven pattern on the surface of the skin material according to the present disclosure include, but are not limited to, the patterns shown in Figures 1 to 10, which will be described later as examples.

From the viewpoint of the ease of wiping off dirt, the uneven surface of the skin material according to the present disclosure preferably has a three-dimensional surface roughness of 1.637 μm or less, and more preferably 1.500 μm or less. The three-dimensional surface roughness (Sa) was determined by measuring the two-dimensional roughness in at least four directions on the surface side of the skin material at a measurement pitch of 20 μm intervals using a skin material 10 mm long and 10 mm wide, and calculating the arithmetic average roughness according to the following formula (1).

In the above formula (1), Z(x, y) represents the surface shape curve Z measured with the average plane as the XY plane and the vertical direction (thickness direction) as the Z axis, dx and dy represent the measured length in the x direction and the measured length in the y direction, respectively, and A represents the measured area.

Specifically, the three-dimensional surface roughness (Sa) is measured using a contact-type three-dimensional surface roughness meter ("Surfcorder SE-30K" manufactured by Kosaka Laboratory Co., Ltd.), analyzed using three-dimensional surface shape analysis software ("Surftop Eye" manufactured by Mitani Shoji Co., Ltd.), and calculated using the above formula (1).

Next, other examples of the uneven shape of the synthetic resin skin material according to the present disclosure will be described. Each of Figs. 13 to 18 shows an example of the uneven shape in a cross section where the unevenness difference is maximum in the synthetic resin skin material according to the present disclosure. In each example, the uneven shape satisfies all of conditions (1) to (3), and the preferred range of each condition is the same as the preferred range described above for the skin material 10 shown in Fig. 12. In addition, the arrangement in the length direction and width direction of the skin material, the geometric pattern formed by the unevenness pattern, and the three-dimensional surface roughness of the surface are also the same as those of the skin material shown in Fig. 12.

In the skin material 20 shown in FIG. 13, the tops of the convex portions 22 are flat, and the bottoms of the concave portions 24 are also flat. In the skin material 20 shown in FIG. 13, the distance between the tops of adjacent convex portions 22 in the horizontal direction is the opening length X of the concave portion 14.

Figure 14 shows a convex portion 32 having a shape in which the angle of the inclined portion changes stepwise. In a convex portion 32 having such a shape, the angle α is defined as a straight line L along the inclined portion of the convex portion 32, which is an extension of the line segment closest to the apex among the multiple line segments that make up the inclined portion of the convex portion 32.

15 shows a protrusion 42 having a curved inclined portion. In the protrusion 42 having such a shape, the angle α is defined as a straight line L along the inclined portion that is parallel to a straight line passing through both ends of the inclined portion and is tangent to the inclined portion of the protrusion 42.
In addition, when the shape of the convex portion is curved only near the apex, as shown in an exaggerated manner in Figure 2 (C) and Figure 10 (C) in the examples described later, the angle α is defined as a straight line L along the inclined portion, which is an extension of the straight line portion excluding the vicinity of the apex.

16 shows an uneven shape in which the convex portions 52 are asymmetric. Each convex portion 52 has two apexes P1 and P2 of different heights, and the inclination angle α of the convex portion 52 is set so that the higher (thicker) apex P1 satisfies condition (1). That is, the angle between the horizontal line H that contacts the apex P1 of the convex portion 52 and the line L1 along the inclined portion on the right side of the paper is α1, and the angle between the line H and the line L2 along the inclined portion on the left side of the paper is α2. Both of these angles α1 and α2 are in the range of 160° to 178°.
On the other hand, the opening length X of the recess 54 is the horizontal distance between the tops P1 and P2 of the adjacent protrusions 52.
In this disclosure, the "top" of a convex portion is a portion that contributes to forming an intended pattern by the concave-convex pattern, and for example, as shown in Figure 6 described below, the portion where the slope is gentle from the convex portion to the concave portion may be considered as part of the slope rather than as the top.

17, the convex portions 62 have asymmetric shapes, and the bottom depths of the concave portions 64 vary horizontally. In the case of a skin material 60 having convex portions 62 of this shape, the angle α1 between a horizontal line H that contacts the tops of the convex portions 62 and a line L1 along the inclined portion on the right side of the paper, and the angle α2 between the line H and a line L2 along the inclined portion on the left side of the paper, are both in the range of 160° to 178°.
The distance in the thickness direction (vertical direction) from the top of the projection 62 to the deepest position of the recess 64 is defined as the depth Y1, Y2 of the recess 64, and both Y1 and Y2 are in the range of 0.1 mm to 0.4 mm. Also, the opening lengths X1, X2 of each recess 64 are both 2 mm to 13 mm.

Figure 18 shows an example of an uneven pattern in which two types of convex portions 72A, 72B with different cross-sectional shapes are alternately formed in the horizontal direction. To the right of the convex portion 72B on the right side of the paper, a convex portion (not shown) similar to the convex portion 72A on the left side is formed. In the case of such an uneven shape, all of the following conditions are met.

(Convex portion 72A and concave portion 74A)
The convex portion 72A on the left side of the drawing has an angle α1 between a horizontal line H1 (direction D) contacting the top and a line L1 along the right-side inclined portion in the range of 160° to 178°.
Moreover, the opening length X1 of the recess 74A is in the range of 2 mm to 13 mm.
Furthermore, the depth Y1 of the recess 74A is in the range of 0.1 mm to 0.4 mm.

(Convex portion 72B and concave portion 74B)
The convex portion 72B on the right side of the drawing forms an angle α2 between a horizontal line H2 (direction D) that contacts the top and a line L2 along the left inclined portion of the convex portion 72B, and forms an angle α3 between the line H2 and a line L3 along the right inclined portion of the convex portion 72B. Both α2 and α3 are in the range of 160° to 178°.
Moreover, the opening length X2 of the recess 74B is in the range of 2 mm to 13 mm.
Furthermore, the depth Y2 of the recess 74B is in the range of 0.1 mm to 0.4 mm.

Next, the layer structure and constituent materials of the skin material according to the present disclosure will be described.
The skin material according to the present disclosure is artificial leather, synthetic leather, PVC leather, or the like.
The skin material according to the present disclosure includes a skin layer containing a synthetic resin, and the uneven pattern formed on the surface of the skin material is not particularly limited as long as it satisfies all of the above-mentioned conditions (1) to (3). The skin material according to the present disclosure may be a single-layer product consisting of only a skin layer, or a multi-layer product in which a skin layer is laminated with one or more other layers. In the case of a multi-layer product, the layer structure includes, for example, a base fabric and a skin layer.

The skin material according to the present disclosure may be made of the same material as known skin materials.
For example, the skin layer is made of synthetic resin such as polyurethane, polyvinyl chloride, etc. The resin constituting the skin material can be selected depending on the application of the skin material, and may contain a plasticizer, a stabilizer, a filler, a colorant, etc.
The base fabric may be made of knitted fabric, woven fabric, nonwoven fabric, or the like.

When the skin material according to the present disclosure has a multi-layer structure, it may include layers other than the skin layer and the base fabric.
19 shows an example of the layer structure of a skin material according to the present disclosure. The skin material 100 is formed by laminating a base fabric 130 and a skin layer 110 via an adhesive layer 120. The surface of the skin layer 110 is formed with irregularities 114, 112 that satisfy all of the above-mentioned conditions (1) to (3).

Figure 20 shows another example of the layer structure of the skin material according to the present disclosure. The skin material 200 further includes a foam layer 140 disposed between the skin layer 110 and adhesive layer 120 of the skin material 100 shown in Figure 19. The foam layer 140 can be formed, for example, by foaming a synthetic resin such as PVC with a foaming agent to form a layer having a porous structure. The inclusion of the foam layer 140 can result in a skin material 200 with high elasticity.

The skin material according to the present disclosure may have other layers on the surface of the skin layer 110 on which the irregularities are formed. For example, a surface treatment layer for the purpose of imparting a good feel can be included. Even if other layers are formed on the surface of the skin layer 110, the irregularity pattern on the surface of the skin material should satisfy all of the above-mentioned conditions (1) to (3).

The thickness of the skin material according to the present disclosure is not particularly limited, but from the viewpoint of the strength and ease of handling of the skin material, a thickness of 0.45 mm to 1.8 mm is preferable, and a thickness of 0.9 mm to 1.2 mm is more preferable.

(Method of manufacturing the skin material)
Although there are no particular limitations on the method for producing a synthetic resin skin material according to the present disclosure, it is preferable to form irregularities that satisfy conditions (1) to (3) by embossing the surface of the skin material before the irregular pattern is formed using an embossing roll or embossing plate. That is, the method for producing a skin material according to the present disclosure includes the steps of preparing a synthetic resin sheet including a synthetic resin layer for forming the skin layer according to the present disclosure, and embossing the synthetic resin layer using an embossing roll or embossing plate to form an irregularity pattern that satisfies all of conditions (1) to (3) on the surface of the synthetic resin sheet.

Examples of synthetic resin sheets including a synthetic resin layer for forming a surface layer include a single-layer sheet including only a synthetic resin layer, and a laminated sheet including a synthetic resin layer and a base fabric, etc. The synthetic resin layer may contain, in addition to the synthetic resin, a plasticizer, a stabilizer, a filler, a colorant, an ultraviolet absorbing agent, etc.
Next, the synthetic resin layer of the prepared synthetic resin sheet is embossed using an embossing roll or an embossing plate to form a concave-convex pattern on the surface of the synthetic resin sheet.

For example, when manufacturing a skin material 100 having the layer structure shown in FIG. 19, a skin layer-forming composition containing a synthetic resin or the like is applied to the surface of a release paper using a knife coater to form a skin layer-forming composition layer on the surface of the release paper. A base fabric is attached to the skin layer-forming composition layer via an adhesive to produce a laminate of the base fabric, adhesive layer, and skin layer. The release paper is peeled off from the laminate, and the skin layer is embossed using an embossing roll or embossing plate with a predetermined uneven pattern. This makes it possible to manufacture a skin material 100 having an uneven pattern formed on its surface that satisfies conditions (1) to (3).

When manufacturing the skin material 200 having the layer structure shown in FIG. 20, a laminate of a skin layer containing a synthetic resin, etc. and a foam layer-forming composition layer containing a synthetic resin, a foaming agent, etc. is formed using a calendar device or the like, and a base fabric is attached to the foam layer-forming composition layer via an adhesive. Next, the foaming agent is foamed by heating. Next, the skin layer is embossed using an embossing roll or embossing plate with a predetermined uneven pattern. This makes it possible to manufacture the skin material 200 having an uneven pattern formed on its surface that satisfies conditions (1) to (3).

In addition, one way to make the three-dimensional surface roughness of the uneven surface of the skin material 1.637 μm or less is to not form fine unevenness such as pores, fibers, or hairlines on the surface.

The method for manufacturing the skin material according to the present disclosure may include other steps. The other steps may be publicly known steps. For example, there may be a step of cutting the skin material into a predetermined shape after embossing.

The synthetic resin skin material of the present disclosure will be specifically described below using examples, but the present disclosure is not limited to these examples.

(Step I) Formation of skin material I-(1) Skin material a (PVC leather)
Using a calendar device, a laminate was formed of a surface layer made of PVC resin blended with a plasticizer, a stabilizer, a filler, a colorant, etc., and a foam layer-forming composition layer made of PVC resin blended with a foaming agent, a plasticizer, a stabilizer, a filler, a colorant, etc.
A knitted fabric was attached to the foam layer-forming composition layer via an adhesive, and the resulting mixture was passed through a heating furnace to foam the foaming agent, thereby forming a foamed resin layer containing bubbles therein, and a skin material a having a thickness of 1.2 mm was obtained.

I-(2) Skin material b (urethane synthetic leather)
A polyurethane resin was diluted with a solvent to prepare a composition for forming a surface layer.
The composition for forming a skin layer was applied to the surface of the release paper with a knife coater to form a composition layer for forming a skin layer on the surface of the release paper.
A knitted fabric was attached to the layer of the composition for forming a surface layer via an adhesive, and then the resulting mixture was aged and cured to obtain a surface material b having a thickness of 0.9 mm.

(Step II) Formation of Concave and Convex Shapes A predetermined concave and convex pattern was formed on the skin layer side of the skin materials a and b obtained as described above by any one of the following embossing processes.
II-(1) Embossing with an embossing roll
II-(2) Embossing with an embossing plate

Example 1
An embossing roll was used to form the uneven pattern shown in FIG. 1(A) on a skin material a (PVC leather).

Example 2
The uneven pattern shown in FIG. 1A was formed on the skin material b (urethane synthetic leather) using an embossing roll.

Example 3
The concave-convex pattern shown in FIG. 2A was formed on a skin material a (PVC leather) using an embossing plate.

Example 4
The concave-convex pattern shown in FIG. 2A was formed on the skin material b (urethane synthetic leather) using an embossing plate.

Example 5
The uneven pattern shown in FIG. 3A was formed on a skin material a (PVC leather) using an embossing roll.

Example 6
The concave-convex pattern shown in FIG. 3A was formed on the skin material b (urethane synthetic leather) using an embossing roll.

Example 7
The concave-convex pattern shown in FIG. 4A was formed on a skin material a (PVC leather) using an embossing plate.

Example 8
The concave-convex pattern shown in FIG. 4A was formed on the skin material b (urethane synthetic leather) using an embossing plate.

<Example 9>
The uneven pattern shown in FIG. 5A was formed on a skin material a (PVC leather) using an embossing roll.

Example 10
The concave-convex pattern shown in FIG. 5A was formed on the skin material b (urethane synthetic leather) using an embossing roll.

Example 11
The uneven pattern shown in FIG. 6A was formed on a skin material a (PVC leather) using an embossing roll.

Example 12
The concave-convex pattern shown in FIG. 6A was formed on the skin material b (urethane synthetic leather) using an embossing roll.

<Example 13>
The concave-convex pattern shown in FIG. 7A was formed on a skin material a (PVC leather) using an embossing plate.

<Example 14>
The concave-convex pattern shown in FIG. 7A was formed on the skin material b (urethane synthetic leather) using an embossing plate.

Example 15
The uneven pattern shown in FIG. 8A was formed on a skin material a (PVC leather) using an embossing roll.

<Example 16>
The concave-convex pattern shown in FIG. 8A was formed on the skin material b (urethane synthetic leather) using an embossing roll.

<Example 17>
The concave-convex pattern shown in FIG. 9A was formed on a skin material a (PVC leather) using an embossing plate.

<Example 18>
The concave-convex pattern shown in FIG. 9A was formed on the skin material b (urethane synthetic leather) using an embossing plate.

<Example 19>
The uneven pattern shown in FIG. 10(A) was formed on a skin material a (PVC leather) using an embossing roll.

<Example 20>
The concave-convex pattern shown in FIG. 10A was formed on the skin material b (urethane synthetic leather) using an embossing roll.

<Comparative Example 1>
The uneven pattern shown in FIG. 11A (conventional uneven pattern) was formed on a skin material a (PVC leather) using an embossing roll.

<Comparative Example 2>
The concave-convex pattern shown in FIG. 11A was formed on the skin material b (urethane synthetic leather) using an embossing roll.

[evaluation]
For each of the skin materials after embossing, the shape of the surface irregularities and the three-dimensional surface roughness in a cross section including a line connecting the points where the thickness of the surface irregularities is greatest and the points where it is smallest, i.e., in a cross section at observation position D on the plane shown in (A) of each figure, were measured using the device described above, and the dirt wiping property and design property were also evaluated.
In each figure, (B) shows a cross-sectional shape along the measurement position shown in (A), and (C) shows a cross-sectional shape in which the depth (thickness) of the cross-sectional shape shown in (B) is enlarged by 10 times to make the cross-sectional shape at the measurement position easier to understand. In each figure, for convenience, the inclination angle α (α1, α2) of the convex portion, the opening length X (X1, X2) of the concave portion, and the depth Y (Y1, Y2) of the concave portion are shown in the cross-sectional shape of (C), but the measurement was performed based on the actual cross-sectional shape shown in (B).

<Easy to wipe off dirt>
(Test Method)
1: Mix 2g of red soil (Kanto Loam layer) with 1.4ml of water to make mud.
2: 0.1 g of mud was rubbed onto the uneven surface of the epidermis layer with a finger.
3: The mud that was rubbed onto the uneven surface of the epidermis layer is lightly wiped off with a cloth dampened with water.

(Evaluation Method)
After the above-mentioned mud test, the color of the surface layer was visually confirmed and evaluated according to the following evaluation criteria.
(Evaluation Criteria)
A: The color of the epidermis layer in the wiped area is visible. B: The color of the epidermis layer in the wiped area is not visible.

<Design>
(Evaluation Method)
The appearance of the skin material produced in each example was visually observed from a position 50 cm away from the surface of the skin material and evaluated according to the following criteria. The results are shown in Table 1.
(Evaluation Criteria)
A: The appearance showed a distinctive design different from that of conventional skin materials. B: The appearance was the same as that of conventional skin materials.

The results are shown in Tables 1 to 3 below.

All of the skin materials in the examples were rated higher in terms of ease of wiping off dirt and design compared to the skin materials in the comparative examples.

10, 20: skin material 12, 22, 32, 42, 52, 62; 72A, 72B: protruding portion 14, 24, 54, 64; 74A, 74B: recessed portion 100, 200: skin material 110: skin layer 120: adhesive layer 130: base fabric 140: foam layer

Claims (5)

A synthetic resin skin material including a skin layer containing a synthetic resin, the synthetic resin skin material having a concave-convex pattern formed on the surface thereof, the concave-convex shape of the surface in a cross section including a point where the thickness of the concave-convex surface is greatest and a point where the thickness is smallest, satisfies all of the following conditions (1) to (3), and the three-dimensional surface roughness of the surface having the concave-convex surface is 1.637 μm or less :
(1) The convex portion has an apex and an inclined portion inclined from the apex toward the bottom of the adjacent concave portion, and is in contact with the apex. Of the two angles formed by the intersection of a line perpendicular to the thickness direction of the skin material and a line along the inclined portion, the angle on the side including the convex portion is 160° to 178°.
(2) The opening length of the recess in a direction perpendicular to the thickness direction of the skin is 2 mm to 13 mm.
(3) The depth of the recess is 0.1 mm to 0.4 mm. The synthetic resin skin material according to claim 1, wherein the projections and recesses are arranged in a repeated pattern in at least one of the length direction and width direction of the synthetic resin skin material. The synthetic resin skin material according to claim 2, wherein the projections and recesses are arranged in a repeating pattern in both the length direction and width direction of the synthetic resin skin material. The synthetic resin skin material according to any one of claims 1 to 3, wherein the projections and recesses are arranged to present a geometric pattern over the entire surface of the synthetic resin skin material. A method for producing the synthetic resin skin material according to any one of claims 1 to 4 , comprising the steps of: preparing a synthetic resin sheet including a synthetic resin layer for forming the skin layer;
a step of embossing the synthetic resin layer using an embossing roll or an embossing plate to form a concave-convex pattern on the surface of the synthetic resin sheet, the concave-convex pattern satisfying all of the conditions (1) to (3) and having a three-dimensional surface roughness of 1.637 μm or less ;
A method for producing a synthetic resin skin material, comprising: