Molded articles of rubber or elastomer compositions

Abstract

The present invention relates to providing a molded article of a rubber or elastomer composition that has a smooth texture and good feel. [Solution] A molded article of a rubber or elastomer composition, wherein the molded article has a rough surface, and the core space volume Vvc of the contour curved surface on the rough surface, in accordance with JIS B 0681-2:2018, is 45 ml / m². 2 The above-mentioned molded article wherein the A hardness of the rubber or elastomer composition is 85 points or less.

Description

[Technical Field]

[0001] The present invention relates to a molded article of a rubber or elastomer composition having a specific rough surface. [Background technology]

[0002] Conventionally, molded articles of various rubber or elastomer compositions have been proposed for the purpose of imparting a sense of luxury and tactile feel to automotive interior and exterior parts, railway vehicle and aircraft interior parts, furniture, shoes, footwear, bags, building interior and exterior components, clothing coverings and linings, wall coverings, etc. For example, Patent Document 1 proposes a synthetic resin surface material that can form a molded article with an excellent appearance, comprising a base layer containing a thermoplastic resin, an intermediate layer provided on one surface of the base layer and containing a polyvinyl chloride resin, and a surface layer provided on the side of the intermediate layer opposite to the base layer, having irregularities on the surface opposite to the intermediate layer, and containing a fluororesin. Furthermore, Patent Document 2 proposes a resin molded product that enables low gloss and improved scratch resistance, comprising a base having an uneven surface pattern composed of multiple peaks and valleys between adjacent peaks, a plurality of first minute protrusions formed on the peaks and spaced apart from each other, and a plurality of second minute protrusions formed on the valleys, having a smaller volume than the first minute protrusions and also spaced apart from each other. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-177499 [Patent Document 2] Japanese Patent Publication No. 2016-107598 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, Patent Document 1 describes a multilayer structure including a base layer, an intermediate layer, and an epidermal layer, resulting in a complex manufacturing process, and does not mention the tactile feel. Patent Document 2 excels in the luxurious feel of its matte surface, but there is room for improvement in terms of tactile feel.

[0005] The present invention relates to providing a molded article of a rubber or elastomer composition that has a smooth texture and good feel. [Means for solving the problem]

[0006] The present invention relates to the following [1] to

[12] . [1] A molded article of a rubber or elastomer composition, wherein the molded article has a rough surface, and the core space volume Vvc of the contour curved surface in accordance with JIS B 0681-2:2018 on the rough surface is 45 ml / m² 2 The above-mentioned molded article wherein the A hardness of the rubber or elastomer composition is 85 points or less. [2] The molded article according to [1], wherein the A hardness of the rubber or elastomer composition is 10 points or more. [3] The molded article according to [1] or [2], wherein the ratio of Vvc to the volume Vvv of the protruding valley space of the contour curved surface in accordance with JIS B 0681-2:2018 on the rough surface (Vvc / Vvv) is 20 or less. [4] The Vvv is 5 ml / m 2 The above is the molded article described in [3]. [5] The molded article according to any one of [1] to [4], wherein the rubber or elastomer composition comprises at least one selected from the group consisting of olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, ethylene vinyl acetate-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, acrylic-based thermoplastic elastomers, and polyamide-based thermoplastic elastomers. [6] The molded body according to any one of [1] to [5], wherein the molded body is an injection molded body. [7] The rough surface is a surface corresponding to an injection molding mold having a plurality of recesses formed therein, and the base portion and the convex portion of the rough surface are integrated. The molded article according to [6]. [8] The depth of the recess is 50 to 400 μm. The molded article according to [7]. [9] The maximum width of the opening of the recess is 50 to 300 μm. The molded article according to [7].

[10] The number of the recesses per unit area is 6 to 500 pieces / mm 2 The molded article according to [7].

[11] The recesses are provided evenly. The molded article according to [7].

[12] The openings of the recesses are separated, and the distance between the openings is 5 to 300 μm. The molded article according to [7].

Advantages of the Invention

[0007] According to the present invention, a molded article of a rubber or elastomer composition having a smooth and good tactile feeling can be provided.

Brief Description of the Drawings

[0008] [Figure 1] The arrangement of the recesses provided in the molds in Examples 1 to 3, 5 to 9 and Comparative Examples 1 to 6 is shown on the left side. Also, the arrangement of the recesses provided in the mold in Example 4 is shown on the right side. [Figure 2] An aspect in which the molded article of the present invention is used as a laminate on the surface (left figure) and a specific example of production using a mold (right figure) are shown.

Modes for Carrying Out the Invention

[0009] The inventors have newly found that, by providing a specific rough surface on the surface of a molded body of a rubber or elastomer composition having a specific A hardness, surprisingly, smoothness is imparted and a molded body with a good touch can be obtained. Although this mechanism is not clear, on a smooth surface, even in a flexible material, the additional stress concentrates at a single point on the surface touched by the fingertip, resulting in a touch feeling where the repulsive force is strongly felt, and when stroking with the fingertip, the slipperiness is poor and it has a catching feeling. On the other hand, the rough surface of the molded body of the present invention has irregularities of a specific hardness and a specific contour curved surface, and its touch feeling is the feeling of touching the tip of a fine convex portion or the feeling of the convex portion being flexible. That is, since the force of the fingertip is dispersed and received by a plurality of convex portions, it feels softer than a flat surface, has a smooth touch without a catching feeling, similar to the texture of so-called suede leather, and it is presumed that the convex portions do not completely bend and fall down and maintain an appropriate repulsive force.

[0010] Further, the inventors have newly found that, by providing a specific rough surface on the surface of a molded body of a rubber or elastomer composition having a specific A hardness, a molded body with warmth in addition to smoothness can be obtained. Although this mechanism is not clear, a molded body containing a gas layer, similar to general foamed styrene, feels warm because its thermal conductivity is low. The rough surface of the molded body of the present invention has a plurality of fine convex portions and concave portions and contains a large amount of air layers, so its thermal conductivity is lowered. In particular, when the fingertip touches, compared to the convex portions that are easily flexible, the concave portions are less likely to deform, so the air layers in the concave portions are less likely to be crushed, and it is presumed that the more concave portions there are, the easier it is to feel warmth.

[0011] The molded body of the rubber or elastomer composition of the present invention (hereinafter, also simply referred to as "the molded body of the present invention") has a rough surface provided with a plurality of fine convex portions and concave portions. The molded body of the present invention only needs to have the rough surface on at least a part of its surface, and it may have a surface other than the rough surface. For example, a mode of a molded body having a smooth surface and the rough surface can be cited.

[0012] The rubber or elastomer composition for the molded article of the present invention may be a composition using a known rubber or elastomer material with a known resin or additive. For example, the rubber material can be natural rubber, styrene-butadiene rubber, ethylene propylene rubber, urethane rubber, acrylic rubber, silicone rubber, etc. The elastomer material can be olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, ethylene vinyl acetate-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, acrylic-based thermoplastic elastomer, polyamide-based thermoplastic elastomer, etc., and one or more of these may be used. Among the rubber and elastomer materials, elastomer materials are preferred from the viewpoint of productivity. From the viewpoint of flexibility and moldability, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, and ethylene vinyl acetate-based thermoplastic elastomer are more preferred, and from the viewpoint of durability, styrene-based thermoplastic elastomer is even more preferred.

[0013] The rubber or elastomer composition according to the present invention may use any resin material or additives, as long as the effects of the invention are not impaired. As resin materials, thermoplastic resins that mechanically and thermally reinforce the rubber or elastomer material can be used, such as crystalline polyolefin resins, polyphenylene ether resins, and polystyrene resins. As additives, rubber softeners, plasticizers, and waxes can be used to impart moldability and flexibility. Antioxidants, anti-aging agents, UV absorbers, and light absorbers can be used to impart long-term durability. Foaming agents can be used to improve warmth and reduce weight. Silicone oils, antifungal agents, and antibacterial agents can be used to impart water repellency and hygiene to the surface. Tackifiers can be used to impart adhesion to dissimilar materials. Inorganic fillers and organic fillers can be used as bulking agents.

[0014] The rubber or elastomer composition relating to the molded article of the present invention can be obtained by known methods, for example, by supplying a mixed powder of composition raw materials to an injection molding machine, kneading it in the injection molding machine, and forming an injection molded article, or by mixing the composition raw materials in advance to obtain a powder or pelletized composition. Known mixing and kneading devices can be used to obtain a powder or pelletized composition in advance. Examples include batch heating and kneading devices such as Banbury mixers, continuous heating and kneading devices such as single-screw extruders and twin-screw extruders, and semi-batch heating and kneading devices such as calender mixers.

[0015] The A hardness (hardness according to JIS K6253-3 Type A durometer) of the rubber or elastomer composition relating to the molded article of the present invention is important. If it is too high, it will have a rough texture, and if it is too low, the air layer on the rough surface will easily collapse. From the viewpoint of a desirable texture, it is preferably 85 points or less, and from the viewpoint of warmth qmax, it is preferably 10 points or more. The A hardness is preferably 20 to 85 points, more preferably 25 to 80 points, and even more preferably 25 to 70 points. In this specification, the A hardness is measured using a Type A durometer in accordance with JIS K 6253, using a sample of three sheets (total 6 mm) with dimensions of 125 mm width × 125 mm length × 2 mm thickness, prepared by injection molding under the following conditions. The A hardness at a measurement time of 15 seconds (value 15 seconds after the start of the test) is measured. The measurement is performed after conditioning for one day in a room at a temperature of 23°C and a humidity of 50%.

[0016] <Injection molding conditions> Injection molding machine: EC100SXII-4B (product name, manufactured by Toshiba Machine Co., Ltd.) Injection molding temperature: 160~200℃ Injection pressure: 120 MPa, Holding pressure: 10 MPa Injection time: 2sec Mold temperature: 40℃

[0017] The rough surface of the molded article of the present invention is provided with a plurality of fine protrusions and recesses. A preferred embodiment of the rough surface of the molded article of the present invention is a surface corresponding to an injection molding die having a plurality of perforated recesses, and it is preferable that the base portion and the protrusions of the rough surface are integrated. Such a rough surface can be formed by transferring an injection molding die in which the plurality of recesses are separated from each other. The arrangement of the recesses of the molding die is not particularly limited, but examples include a so-called square lattice arrangement where the recesses 2a perforated in the smooth surface 1a of the molding die are aligned in a plan view looking down from above, as shown on the left side of Figure 1, and a so-called triangular lattice arrangement where the recesses 2b perforated in the smooth surface 1b of the molding die are arranged alternately, as shown on the right side of Figure 1. The longitudinal cross-sectional shape from the upper opening to the lower end of the recess in a side view is not particularly limited, but can be, for example, a roughly conical, roughly pyramidal, roughly frustoconical, or roughly frustoconical shape. From the viewpoint of transferability of the recess of the mold, a roughly conical or roughly frustoconical shape is preferred, and from the viewpoint of a pleasant tactile feel, a roughly conical shape is more preferred. When using the mold, for example, in thermoplastic resin molding, the resin component (molten resin) that has been heated and melted into a fluid state flows into the recesses 2a and 2b of the mold, and the portion that cools and solidifies becomes the convex portion 5 (see Figure 2) on the rough surface of the molded body. In addition, the resin component that cools and solidifies while in contact with the smooth surfaces 1a and 2a of the mold becomes the flat portion 7 (see Figure 2) on the rough surface or the recess 6a (see Figure 2) on the rough surface due to shrinkage caused by cooling. Furthermore, as the resin component flows in, the air that was in the recesses 2a and 2b is expelled. If the air remains around the periphery of the openings of the recesses 2a and 2b, the resin component cools and solidifies without touching the smooth surfaces 1a and 2a of the mold. Along with shrinkage due to cooling, this results in a recess 6b that is deeper than the recess 6a of the rough surface (see Figure 2). In Figure 2, the rough surface base portion 8 is formed from the cooled and solidified portion corresponding to the flow path of the molten resin. This molten resin flows further into the recesses 2a and 2b, so the rough surface base portion 8 and the convex portion 5 are formed as a single unit.

[0018] From the perspective of a preferable tactile sensation, the depth of the recess of the shaping mold is preferably 50 μm or more. From the perspective of the transferability of the shaping mold, it is preferably 400 μm or less. The depth of the recess of the shaping mold is more preferably 60 to 350 μm, still more preferably 80 to 300 μm, and still more preferably 120 to 200 μm.

[0019] From the perspective of the transferability of the shaping mold, the maximum width of the opening of the recess of the shaping mold (hereinafter, also simply referred to as "recess opening diameter") is 50 μm or less. From the perspective of a preferable tactile sensation, it is 300 μm or less. The recess opening diameter is more preferably 60 to 250 μm, still more preferably 70 to 200 μm, and still more preferably 80 to 150 μm.

[0020] From the perspective of a preferable tactile sensation, the number of recesses per unit area of the shaping mold (hereinafter, also simply referred to as "recess density") is 6 / mm 2 or more. From the perspective of the warmth qmax, it is 500 / mm 2 or less. The recess density is more preferably 10 to 300 / mm 2 , still more preferably 15 to 200 / mm 2 , still more preferably 20 to 100 / mm 2 , still more preferably 30 to 80 / mm 2 and is.

[0021] It is preferable that the recesses of the shaping mold are provided evenly. In this case, the distance between the recesses is preferably 5 to 300 μm, more preferably 10 to 200 μm, and still more preferably 20 to 100 μm. The distance between the recesses of the shaping mold refers to the shortest distance between the ends of the adjacent recess openings.

[0022] The distance between the openings of the recesses of the shaping mold is also related to the recess density. The ratio of the distance between the openings / the diameter of the recess opening is 1 or less from the perspective of a preferable tactile sensation. From the perspective of the warmth qmax, it is 0.1 or more. The ratio of the distance between the openings / the diameter of the recess opening is more preferably 0.1 to 1, still more preferably 0. / mm

[0023] The cavity size of the above-mentioned mold is such that the relationship between the distance from the inlet (gate) of the molten resin to the cavity end (L) and the cavity thickness (t), L / t, is preferably 1000 or less, more preferably 500 or less, and even more preferably 200 or less, from the viewpoint of dimensional accuracy of the molded product and transferability of the mold.

[0024] The core space volume Vvc (hereinafter also simply referred to as "Vvc") of the contour curved surface in the rough surface of the molded article of the present invention, in accordance with JIS B 0681-2:2018, shows a high value when the rough surface contains many tall, elongated protrusions, and is related to the tactile feel of the flexibility of the protrusions when touched with a fingertip. From the viewpoint of a desirable tactile feel, Vvc is 45 ml / m 2 Preferably 50-100 ml / m² 2 more comfortably 60-90 ml / m² 2 In this specification, Vvc and Vvv (described later) are calculated as the spatial volume in the range of 10% to 80% of the load area ratio of the contour curved surface separating the core portion and the protruding peak portion, and the spatial volume in the range of 80% to 100% of the load area ratio of the contour curved surface separating the core portion and the protruding valley portion. In this specification, Vvc and Vvv (described later) can be measured by the method described in the examples.

[0025] The volume Vvv (hereinafter also simply referred to as "Vvv") of the protruding valley space of the contour curved surface of the molded article of the present invention, in accordance with JIS B 0681-2:2018, shows a high value when the rough surface has many recesses and many air layers, and is related to the warmth qmax when touched with a fingertip. From the viewpoint of warmth qmax, 5 ml / m is preferred. 2 Based on the above, from the viewpoint of a desirable texture, a preferred 25 ml / m² 2 The following is more more preferable: 8-20 ml / m² 2 More preferably 10-18 ml / m² 2 That is the case.

[0026] The ratio of Vvc to Vvv (Vvc / Vvv) on the rough surface of the molded article of the present invention is an indicator of the balance between the convex and concave parts of the rough surface, which are related to the smoothness when touched with a fingertip and the concave parts which are related to the warmth qmax. From the viewpoint of warmth qmax, it is preferably 20 or less, and from the viewpoint of a desirable tactile feel, it is preferably 1 or more, more preferably 1 to 16, even more preferably 2 to 10, and even more preferably 3 to 6.

[0027] The maximum height Sz (hereinafter also simply referred to as "Sz") of the contour curved surface in the rough surface of the molded article of the present invention, in accordance with JIS B 0681-2:2018, is not particularly limited, but from the viewpoint of a desirable tactile feel, it is preferably 160 to 500 μm, more preferably 190 to 400 μm, and even more preferably 210 to 350 μm. Sz is measured by the method described in the examples.

[0028] The warmth qmax on the rough surface of the molded article of the present invention is not particularly limited, but a lower value indicates less heat transfer and therefore superior warmth. Preferably, it is 0.01 to 0.30 W / cm². 2 , more preferably 0.02~0.25 W / cm² 2 More preferably 0.05 to 0.20 W / cm² 2 That is the case.

[0029] The thickness t of the roughened base portion of the molded article according to the present invention is preferably 0.1 mm or more, more preferably 0.3 mm or more, even more preferably 0.5 mm or more, and even more preferably 1 mm or more, from the viewpoint of mold transferability. The upper limit is not particularly limited, but for example, it may be 10 mm or less, 5 mm or less, or 3 mm or less. The thickness t of the roughened base portion refers to the thickness excluding the height of the protrusions (see Figure 2).

[0030] The molded articles of the present invention can be formed by known methods such as extrusion molding, press molding, vacuum molding, injection molding, and blow molding, but it is preferable that they be formed by injection molding because the rough surface according to the present invention can be formed on curved surfaces, complex shapes, and in localized areas. More specifically, a manufacturing method having a step of transferring the surface shape of a mold with multiple recesses to form a rough surface is preferably exemplified.

[0031] The recesses in the mold described above are preferably perforations and are formed by known mold processing methods. For example, laser processing, etching, sandblasting, and cutting methods such as drilling can be used. Laser processing is preferred from the viewpoint of precision in microfabrication. The material used for the mold can also be a known material such as a metal or resin, and a metal material, or so-called mold, is preferred from the viewpoint of durability.

[0032] Furthermore, laminates can be manufactured in which the surfaces of parts made of the same material or parts made of different materials are partially or entirely covered by injection molding methods such as insert molding or two-color molding on the surfaces of the same material or different materials. Such molded articles containing the same material or different materials are also included in the present invention. An example of an embodiment containing the same material or different materials as a base material is the embodiment shown in Figure 2, in which a rough surface 4 is molded on the surface of the base material 3. Here, the same material refers to a resin material containing the molecular chain structure that constitutes the rubber material or elastomer material used in the rubber or elastomer composition according to the present invention. For example, in the case of a styrene-based thermoplastic elastomer material having polystyrene molecular chains and molecular chains resulting from a conjugated diene polymer, the same material can be a polystyrene-based resin (PS, HIPS, ABS, etc.), a polyolefin-based resin (LDPE, HDPE, PP, etc.), a butadiene-based rubber (BR, NBR, SBR, etc.), and the dissimilar material can be a hard resin material such as polycarbonate resin, polyester resin, or polyamide resin, as well as metal materials and wood materials. Alternatively, the same-type and different-type materials may be based on the solubility parameter (also known as the SP value) of the rubber or elastomer composition according to the present invention.

[0033] The molded articles of the present invention are smooth and, more preferably, have a pleasant, warm feel, making them suitable for use in various applications where these characteristics are required. Examples of such applications include the interiors of automobiles, trains, and aircraft; the surfaces of game console controllers, smartphone covers, and remote control devices; the surfaces of furniture; and building materials such as wallpaper and doorknobs. [Examples]

[0034] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way by these examples. The shaping molds and various physical properties of the molded articles used in the examples were measured by the following methods.

[0035] [Depth of recess in the mold (mold), diameter of recess opening, density of recess, distance between recess openings, base diameter of frustoconical recess] The recesses on the inner surface of the cavity of an injection molding die were measured using a KEYENCE laser microscope (VK-X1050). Recess depth, recess opening diameter, recess density (1mm 2 Tables 1 and 2 show the values ​​for the number of openings per unit area, the distance between recessed openings (the shortest distance between the ends of adjacent recessed openings), and the diameter of the base of the frustoconical shape. <Measurement conditions> Magnification: 10x Scan mode: Laser confocal Software: Multi-file analysis application Processing procedure: Execute image processing rule - Reference plane setting. Measurement area: approx. 1500000μm 2 (0.0015mm 2 )

[0036] [Vvc, Vvv, and Sz measurement of molded parts] In accordance with JIS B 0681-2:2018, Vvc was measured in the load curves with a load area ratio of 10-80%, and Vvv, Sz, and Sa were measured in the load curves with a load area ratio of 80-100% under the following conditions using a KEYENCE laser microscope (VK-X1050). The results are shown in Tables 1 and 2. <Measurement conditions> Magnification: 10x Scan mode: Laser confocal Software: Multi-file analysis application Processing procedure: Execute image processing rule - Reference plane setting. Measurement area: approx. 1500000μm 2 (0.0015mm 2 )

[0037] <Elastomer composition used and hardness level A> The styrene-based thermoplastic elastomer composition manufactured by Aron Kasei Co., Ltd., as shown below, was used. The hardness is A (JIS K6253-3) as shown in the catalog (https: / / www.aronkasei.co.jp / elastomer / ). TPS-1: AR-1060 (product name), A hardness 60 points TPS-2: AR-SC-15 (product name), A hardness 13 points TPS-3: TF-A30NT (product name), A hardness, 28 points TPS-4: TF-A80NT (product name), A hardness 80 points TPS-5: TF-A90NT (product name), A hardness 88 points

[0038] Examples 1-3, 5-8 and Comparative Examples 1-5 A conical recess of the size shown in Table 1 was created on one surface (60mm x 60mm) of the cavity (a plate shape with a width of 60mm, a length of 60mm, and a thickness of 2mm) of an injection molding die by laser processing, in the arrangement shown on the left side of Figure 1. The die was then installed in an injection molding machine, and a molded body having a rough surface on one side and a smooth surface on the other side was obtained using the elastomer composition shown in Table 1 under the following conditions. <Injection molding conditions> Injection molding machine: EC100SXII-4B (product name, manufactured by Toshiba Machine Co., Ltd.) Injection molding temperature: 160~200℃ Injection pressure: 120 MPa, Holding pressure: 10 MPa Injection time: 2sec Mold temperature: 40℃

[0039] Example 4 A molded body was obtained in the same manner as in Example 3, except that the arrangement of the recesses in the mold was as shown on the right side of Figure 1, and the density of the recesses was increased.

[0040] Example 9 A molded body was obtained in the same manner as in Example 1, except that the shape of the recess in the mold was a frustoconical shape.

[0041] Comparative Example 6 A molded body was obtained in the same manner as in Example 9, except that the shape of the recess in the mold was set to the conditions shown in Table 2.

[0042] [Table 1]

[0043] [Table 2]

[0044] <Warmth q max evaluation> The warmth (q max) of the molded articles for each example and comparative example was measured under the following conditions in accordance with JIS L 1927 "Contact Cooling Test". The results are shown in Tables 1 and 2. (Measurement conditions) Test method: Precision rapid thermophysical property measurement device (KES-F7, Thermolab Type II used) Laboratory temperature and humidity: 20°C, 65%RH Temperature difference between temperature detector and test specimen: 20°C Measurement surface: Smooth surface side

[0045] <Smoothness evaluation> For each example and comparative example, the smoothness of the rough surface of the molded body was evaluated by wiping off any oil or moisture from the rough surface with ethanol, drying it, and then having 10 panelists touch it with their fingertips and lightly rubbing it. The tactile feel of the rough side of the molded body was compared with the smooth side of the molded body and with suede fabric (Toray Industries' Ultrasuede USTS-RC9 (product name)), and evaluated according to the evaluation criteria below. The mode of each panelist's results is shown in Tables 1 and 2. (Evaluation Criteria) 1: Rough texture 2: A texture that feels rough, similar to a smooth surface. 3: It's smooth, but it feels rougher than suede. 4: A smooth, gliding feel similar to suede fabric.

[0046] As shown in Table 1, Examples 1-8 showed better "smoothness" compared to Comparative Examples 1-4. The results from Examples 1-5 and Comparative Examples 1-4 show a high correlation between "Vvc" and "smoothness". Furthermore, in Examples 3-5, which had the same A hardness, a lower "Vvc / Vvv" ratio resulted in a lower warmth qmax, indicating that warmth improved in addition to smoothness. On the other hand, Comparative Example 5 had a rougher texture due to its higher A hardness compared to Examples 1 and 6-8. Furthermore, Examples 1, 7, and 8, which had moderately high A hardness compared to Example 6, showed even lower warmth qmax, indicating improved warmth in addition to smoothness. It should be noted that while Examples 1, 6-8, and Comparative Example 5 all had similar Sz values, their smoothness and warmth differed significantly, indicating no correlation with Sz in any of these aspects. Example 9 was superior to Comparative Example 6 in terms of "smoothness" and "warmth qmax".

[0047] From the above results, it can be seen that molded articles using flexible elastomer materials and having a surface shape controlled within a specific "Vvc" range can be obtained to have a smooth feel, and furthermore, by appropriately adjusting the A hardness, a warm feel can be obtained. Although not shown in the table, in each example and comparative example, the sensory perception of warmth was also confirmed by actually touching with fingertips, and it was confirmed that there was a correlation with "warmth qmax" in all cases. [Industrial applicability]

[0048] The molded articles of the present invention are particularly suitable for use in the interiors of automobiles, trains, and aircraft; the surfaces of game console controllers, smartphone covers, and remote control devices; the surfaces of furniture; and building materials such as wallpaper and doorknobs. [Explanation of Symbols]

[0049] 1a: Shaped smooth surface 1b: Shaped smooth surface 2a: Shaped recess 2b: Recessed part of the shape 3: Base material 4: Rough surface 5: Convex part 6a: recess 6b: recess 7: Flat part 8: Base section Ma: Shaping type Mb: Base-side type t: thickness

Claims

1. A molded article of a rubber or elastomer composition, wherein the molded article has a rough surface, and the core space volume Vvc of the contour curved surface on the rough surface, according to JIS B 0681-2:2018, is 45 ml / m². ２ The above-mentioned molded article wherein the A hardness of the rubber or elastomer composition is 85 points or less.

2. The molded article according to claim 1, wherein the A hardness of the rubber or elastomer composition is 10 points or more.

3. The molded article according to claim 1, wherein the ratio of Vvc to the volume Vvv of the protruding valley space of the contour curved surface in accordance with JIS B 0681-2:2018 in the rough surface (Vvc / Vvv) is 20 or less.

4. The aforementioned Vvv is 5 ml / m ２ The molded article according to claim 3.

5. The molded article according to claim 1, wherein the rubber or elastomer composition comprises at least one selected from the group consisting of olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, ethylene vinyl acetate-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, polyurethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, acrylic-based thermoplastic elastomers, and polyamide-based thermoplastic elastomers.

6. The molded body according to claim 1, wherein the molded body is an injection-molded body.

7. The molded body according to claim 6, wherein the rough surface is a surface corresponding to an injection molding die having a plurality of drilled recesses, and the base portion and the convex portion of the rough surface are integrated.

8. The molded article according to claim 7, wherein the depth of the recess is 50 to 400 μm.

9. The molded article according to claim 7, wherein the maximum width of the opening of the recess is 50 to 300 μm.

10. The number of recesses per unit area is 6 to 500 per mm². ２ The molded article according to claim 7.

11. The molded body according to claim 7, wherein the recesses are evenly distributed.

12. The molded article according to claim 7, wherein the openings of the recesses are separated and the distance between the openings is 5 to 300 μm.

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