Surface material

Abstract

The present invention aims to provide a surface material that is less prone to adhesive seepage. [Solution] The nonwoven fabric of the surface material has a rough main surface (one main surface) due to the low proportion of fine fibers in its constituent fibers. Since most of the adhesive applied to this one main surface of the surface material is retained from that main surface into the interior of the nonwoven fabric, in order to prevent the adhesive from seeping out, it is sufficient to prevent some of the adhesive from passing through to the other main surface. Furthermore, the nonwoven fabric constituting the surface material according to the present invention has a main surface on the other side that has a dense structure due to a high proportion of fine fibers among its constituent fibers. Therefore, the presence of the dense structure of this other main surface prevents some of the adhesives mentioned above from passing over the other main surface of the nonwoven fabric.

Description

[Technical Field]

[0001] This invention relates to a surface material that is less prone to adhesive seepage. [Background technology]

[0002] In recent years, there has been interest in manufacturing interior and exterior materials (hereinafter collectively referred to as interior and exterior materials) by molding laminates, which are formed by bonding a base material and a surface material with an adhesive in between, using methods such as heat molding.

[0003] However, in the manufacturing process of the interior and exterior materials described above, when adhesive was applied to one main surface of the surface material (the main surface that is bonded to the base material), or when it was subsequently subjected to a molding process such as heat molding, the adhesive sometimes seeped to the other main surface (the main surface opposite to the one bonded to the base material). As a result, the manufactured interior and exterior materials suffered from inferior aesthetic appeal.

[0004] As a surface material that can solve such problems, for example, the interior substrate for vehicles (corresponding to the above-mentioned surface material) disclosed in Japanese Patent Application Publication No. 2019-59390 (Patent Document 1) is known. In Patent Document 1, an interior substrate for vehicles is realized in which adhesive does not easily seep out by incorporating a water-repellent agent and / or oil-repellent agent, such as a fluororesin or silicone resin, into a fibrous sheet such as a nonwoven fabric that is part of the interior substrate for vehicles. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-59390 [Overview of the project] [Problems that the invention aims to solve]

[0006] The invention described in Patent Document 1 prevents adhesive seepage by impregnating a fibrous sheet, such as a nonwoven fabric, with a water-repellent and / or oil-repellent agent. However, the water-repellent and / or oil-repellent agents have the problem of being expensive.

[0007] Therefore, there was a need for a surface material that prevents adhesive seepage without the use of water-repellent and / or oil-repellent agents, or a surface material that is resistant to adhesive seepage. [Means for solving the problem]

[0008] The present invention is "(Claim 1)" A surface material comprising a nonwoven fabric containing a first fiber having the smallest average fiber diameter and a second fiber having a larger average fiber diameter than the first fiber, In the nonwoven fabric, the proportion of the first fibers in the fibers constituting the main surface opposite to the first main surface is greater than the proportion of the first fibers in the fibers constituting the main surface of the main surface of the main surface of the main surface of the main fabric. Surface material. (Claim 2) The surface material according to claim 1, wherein the constituent fibers are not bonded to the constituent resin. (Claim 3) A surface material that is bonded to a substrate via an adhesive in between, The surface material comprises a nonwoven fabric containing a first fiber having the smallest average fiber diameter among its constituent fibers and a second fiber having a larger average fiber diameter than the first fiber. In the nonwoven fabric, the proportion of the first fibers in the main surface on the side opposite to the side that is bonded to the substrate is greater than the proportion of the first fibers in the main surface on the side that is bonded to the substrate. Surface material. (Claim 4) An interior and exterior material in which a base material and a surface material according to any one of claims 1 to 3 are bonded together with an adhesive in between, In the nonwoven fabric, the main surface on the side that is in contact with the substrate is the main surface with a smaller proportion of the first fibers. Interior and exterior materials. [Effects of the Invention]

[0009] The surface material according to the present invention is The nonwoven fabric comprises a first fiber (hereinafter sometimes referred to as a fine fiber) having the smallest average fiber diameter among its constituent fibers, and a second fiber (hereinafter sometimes referred to as a thick fiber) having a larger average fiber diameter than the first fiber. The proportion of fine fibers in the fibers constituting one main surface is greater than the proportion of fine fibers in the fibers constituting the opposite main surface (the other main surface). It has the following configuration. Therefore, by bonding the base material and the main surface side of the nonwoven fabric in the surface material with an adhesive in between, it is possible to provide interior and exterior materials in which the leakage of adhesive is prevented.

[0010] The following reasons can be considered for the effects described above.

[0011] The nonwoven fabric of the surface material according to the present invention has a rough main surface (one main surface) due to a low proportion of fine fibers in its constituent fibers. Most of the adhesive applied to this one main surface of the surface material is retained within the nonwoven fabric. Therefore, the only adhesive that may seep to the other main surface of the nonwoven fabric is a portion of the adhesive that has been applied and retained within the nonwoven fabric and has moved toward the vicinity of the other main surface. Thus, to prevent the adhesive from seeping out, it is sufficient to prevent this portion of the adhesive from passing through the other main surface.

[0012] Furthermore, the nonwoven fabric constituting the surface material according to the present invention has a main surface on the other side that has a dense structure due to a high proportion of fine fibers among its constituent fibers. Therefore, the presence of the dense structure of this other main surface prevents some of the adhesives mentioned above from passing over the other main surface of the nonwoven fabric.

[0013] As described above, the surface material provided with the nonwoven fabric according to the present invention can effectively prevent the adhesive from passing from one main surface to the other main surface. Therefore, in the surface material according to the present invention, it is difficult for the adhesive to bleed out.

[0014] Also, in the nonwoven fabric included in the surface material according to the present invention, even if the constituent fibers are not fiber-bonded by the constituent resin (that is, the resin constituting the constituent fibers), as is clear from the examples described later, it is possible to realize a surface material in which it is difficult for the adhesive to bleed out.

[0015] And, in the interior and exterior decoration material in which the base material and the surface material are adhered via an adhesive prepared as described above, the main surface of the nonwoven fabric on the side adhered to the base material is the main surface with a smaller number ratio of fine fibers. Therefore, it is an interior and exterior decoration material in which the above-described effect is exhibited and bleeding of the adhesive is prevented.

Embodiments for Carrying Out the Invention

[0016] In the present invention, various configurations such as the following configurations can be appropriately selected. In addition, unless otherwise specified or defined, various measurements described in the present invention are performed under a temperature condition of 25 ° C under normal pressure. And, unless otherwise specified or defined, various measurement results described in the present invention are measured up to a value one digit smaller than the required value, and the required value is calculated by rounding off the obtained value. As a specific example, when the value up to the first decimal place is the required value, the value up to the second decimal place is obtained by measurement, and the value up to the first decimal place is calculated by rounding off the obtained value of the second decimal place, and this value is used as the required value. Also, the upper limit values and the lower limit values exemplified in the present invention can be arbitrarily combined.

[0017] The surface material according to the present invention includes a nonwoven fabric, and therefore is rich in flexibility and has excellent formability such as being heat-moldable.

[0018] The constituent fibers of nonwoven fabrics include, for example, polyolefin resins (e.g., polyethylene, polypropylene, polyolefin resins with a structure in which some hydrocarbons are replaced with nitrile groups or halogens such as fluorine or chlorine), polymethylpentene, styrene resins, polyvinyl alcohol resins, polyether resins (e.g., polyetheretherketone, polyacetal, modified polyphenylene ether, aromatic polyetherketone, etc.), polyester resins (e.g., polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polycarbonate, polyarylate, fully aromatic polyester resins, etc.), and polyimide resins. It can be constructed using known resins such as polyamide-imide resins, polyamide resins (e.g., aromatic polyamide resins, aromatic polyetheramide resins, nylon resins, etc.), resins having nitrile groups (e.g., polyacrylonitrile, etc.), urethane resins, epoxy resins, polysulfone resins (e.g., polysulfone, polyethersulfone, etc.), fluorine resins (e.g., polytetrafluoroethylene, polyvinylidene fluoride, etc.), cellulose resins, polybenzimidazole resins, and acrylic resins (e.g., polyacrylonitrile resins copolymerized with acrylic acid esters or methacrylic acid esters, modacrylic resins copolymerized with acrylonitrile and vinyl chloride or vinylidene chloride, etc.).

[0019] These resins may consist of either linear or branched polymers, and may be block copolymers or random copolymers. Furthermore, there are no particular limitations on the three-dimensional structure or crystalline properties of the resins. In addition, mixed resins containing multiple resins are also acceptable.

[0020] When flame retardancy is required for the surface material, it is preferable that the constituent fibers of the nonwoven fabric contain a flame-retardant resin. Examples of such flame-retardant resins include modacrylic resin, vinylidene resin, polyvinyl chloride resin, polyvinylidene fluoride resin, novoroid resin, polyclar resin, polyester resin copolymerized with phosphorus compounds, acrylic resin copolymerized with halogen-containing monomers, aramid resin, and resins kneaded with halogen-based, phosphorus-based, or metal compound-based flame retardants.

[0021] The constituent fibers of the nonwoven fabric may be composed of one type of resin or multiple types of resins. Fibers composed of multiple types of resins are generally called composite fibers, and for example, the arrangement of resins in the fiber cross-section can be in the form of core-sheath type, sea-island type, side-by-side type, orange type, bimetal type, etc.

[0022] If the nonwoven fabric contains heat-fusible fibers as its constituent fibers, the constituent fibers may be heat-fused together. Such heat-fusible fibers may be fully fusible heat-fusible fibers or partially fusible heat-fusible fibers, such as the composite fibers described above. As the component that exhibits heat-fusibility in the heat-fusible fibers, for example, polyethylene resin or low-melting-point polyester resin can be used.

[0023] When a nonwoven fabric contains crimpable fibers as its constituent fibers, its elasticity increases, resulting in superior conformability to molds, which is desirable. As such crimpable fibers, for example, crimpable fibers that have undergone crimping from latent crimpable fibers can be used.

[0024] The constituent fibers of the nonwoven fabric may include fibers with irregular cross-sections in addition to fibers with approximately circular or elliptical cross-sections. These irregular cross-section fibers may have cross-sections such as hollow shapes, polygonal shapes like triangles, alphabetic shapes like Y-shapes, irregular shapes, multi-lobed shapes, symbolic shapes like asterisks, or shapes formed by combining multiple such shapes.

[0025] Furthermore, the constituent fibers of the nonwoven fabric may be dope-dyed fibers, such as fibers prepared by kneading in pigment or dyed fibers. In addition, a flame retardant may be supported on the constituent fibers of the nonwoven fabric by using a binder or the like.

[0026] The nonwoven fabric according to the present invention includes a first fiber (fine fiber) having the smallest average fiber diameter as a constituent fiber, and a second fiber (coarse fiber) having a larger average fiber diameter than the first fiber. To achieve a surface material that is less susceptible to adhesive seepage, the average fiber diameter of the fine fiber is preferably 15.2 μm or less, and more preferably 11.8 μm or less. On the other hand, the lower limit can be adjusted as appropriate, but 3.0 μm is practical. Furthermore, the average fiber diameter of the coarse fiber is preferably 13.6 μm or more, and more preferably 16.6 μm or more. On the other hand, the upper limit can be adjusted as appropriate, but 67.9 μm is practical.

[0027] If the manufacturing process of the nonwoven fabric is known, the average fiber diameter of the fiber species used to manufacture the nonwoven fabric is calculated from the fineness and specific gravity of the fiber species used.

[0028] On the other hand, if the manufacturing process of the nonwoven fabric is unknown, the following method can be used to determine its average fiber diameter. First, 100 fibers of the fiber type for which the average fiber diameter is to be determined are randomly selected from an electron microscope image of the main surface of the nonwoven fabric. The main surface refers to the surface with the largest area. Next, the fiber diameter of each of the 100 selected fibers is determined. The fiber diameter can be confirmed in an electron microscope image and represents the length in the direction perpendicular to the direction of fiber growth. Finally, the arithmetic mean of the determined fiber diameters is calculated and used as the average fiber diameter for the fiber species for which the average fiber diameter is to be determined.

[0029] The difference between the average fiber diameter of the fine fibers and the average fiber diameter of the thick fibers is adjusted as appropriate to achieve a surface material that is less prone to adhesive seepage. This difference is preferably 1 μm or more, more preferably 2 μm or more, and most preferably 3 μm or more. The upper limit is adjusted as appropriate, but 10 μm is preferred.

[0030] The ratio of the mass of fine fibers to the mass of coarse fibers that make up the nonwoven fabric is adjusted as appropriate to achieve a surface material that is less susceptible to adhesive seepage. Specifically, a ratio of fine fibers to coarse fibers of 10%:90% to 90%:10% is preferred, and a ratio of fine fibers to coarse fibers of 30%:70% to 70%:30% is more preferred.

[0031] Furthermore, the fiber length of the constituent fibers of the nonwoven fabric is adjusted as appropriate, but it can be short fibers cut to a specific fiber length in order to realize a surface material with good moldability, such as being heat-moldable. The fiber length is preferably 20 mm or more, more preferably 25 mm or more, and even more preferably 30 mm or more. On the other hand, if the fiber length exceeds 110 mm, it may become difficult to realize a surface material with good moldability, such as being heat-moldable, so it is preferably 110 mm or less, and more preferably 60 mm or less. Note that "fiber length" refers to the value measured in accordance with JIS L1015 (2010), 8.4.1c) direct method (Method C).

[0032] The constituent fibers of nonwoven fabrics can be obtained by known methods such as melt spinning, dry spinning, wet spinning, direct spinning (meltblown, spunbond, electrostatic spinning, etc.), methods for extracting fine fibers by removing one or more resin components from composite fibers, and methods for obtaining divided fibers by beating the fibers.

[0033] For example, nonwoven fabrics can be prepared using fiber webs obtained by a dry method in which the fibers are intertwined by feeding them to a carding device or air array device, or by using fiber webs obtained by a wet method in which the fibers are dispersed in a solvent, formed into a sheet, and intertwined. Alternatively, nonwoven fabrics can be prepared using fiber webs obtained by spinning and collecting fibers using a direct spinning method (such as the melt-blown method, spunbond method, electrostatic spinning method, or a method in which a spinning stock and a gas flow are discharged in parallel (for example, the method disclosed in Japanese Patent Publication No. 2009-287138)).

[0034] Furthermore, it is preferable that the constituent fibers of the nonwoven fabric are intertwined and integrated. As a method for intertwining and integrating the constituent fibers, for example, a needle punch treatment or a water jet entanglement treatment can be applied to the fiber web prepared as described above. In particular, in a fiber web containing both fine and thick fibers and in which both fibers are blended, applying the needle punch treatment only from one main surface side, • On the main surface (one main surface) that has undergone needle punching, the proportion of thick fibers in the constituent fibers can be increased, while the proportion of thin fibers in the constituent fibers can be decreased. On the main surface opposite to the side treated with needle punching (the other main surface), the proportion of thick fibers in the constituent fibers can be reduced, while the proportion of thin fibers in the constituent fibers can be increased.

[0035] The nonwoven fabric according to the present invention can be prepared. In particular, it is preferable that the constituent fibers of the fiber web are short fibers, as this makes it easier to prepare the nonwoven fabric according to the present invention.

[0036] Furthermore, the constituent fibers of the nonwoven fabric may be bonded together. The constituent fibers may be bonded together by applying a binder to the fiber web and subjecting it to heat treatment, for example.

[0037] The heat treatment method can be selected as appropriate, but for example, it can be heated or heated and pressurized using a roller, subjected to heating equipment such as an oven dryer, far-infrared heater, dry heat dryer, or hot air dryer, or heated by irradiating with infrared rays under no pressure.

[0038] The type of binder that can be used is selected as appropriate, but examples include polyolefins (such as modified polyolefins), ethylene vinyl alcohol copolymers, ethylene-acrylate copolymers such as ethylene-ethyl acrylate copolymers, various rubbers and their derivatives (such as styrene-butadiene rubber (SBR), fluororubber, urethane rubber, ethylene-propylene-diene rubber (EPDM)), cellulose derivatives (such as carboxymethylcellulose (CMC), hydroxyethylcellulose, hydroxypropylcellulose), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinylpyrrolidone (PVP), epoxy resins, polyvinylidene fluoride (PVdF), vinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), acrylic resins (such as acrylic ester resins and acrylonitrile styrene copolymer resins), and polyurethane resins. It is preferable that the binder contains an acrylic resin, as this can result in a surface material with excellent conformability during molding.

[0039] The basis weight of the binder included in the nonwoven fabric should be selected as appropriate, but a higher binder content may make it more difficult to achieve a surface material with good moldability, such as heat molding. Therefore, the binder basis weight should be 50 g / m². 2 Preferably, it is 30 g / m 2 Preferably, it is 10 g / m 2 Below (ideally 0g / m 2 It is preferable that it be the case.

[0040] Furthermore, the binder may contain additives other than the resins mentioned above, such as flame retardants, fragrances, pigments, antibacterial agents, antifungal agents, and photocatalytic particles.

[0041] The nonwoven fabric according to the present invention has a structure in which the proportion of fine fibers in the fibers constituting one main surface is greater than the proportion of fine fibers in the fibers constituting one main surface.

[0042] Whether or not it has the above configuration can be confirmed by the following method.

[0043] (Method for checking the ratio of fine fibers) (Step 1) Prepare the nonwoven fabric that makes up the surface material. At this time, the nonwoven fabric that makes up the surface material may be prepared by removing components other than the nonwoven fabric from the surface material. Then, cut out and collect a sample from the nonwoven fabric. (Step 2) Take a scanning microscope image A (magnification: 500x or 1000x) of one main surface (main surface A) of the collected sample. Similarly, take a scanning microscope image B (magnification: 500x or 1000x) of the other main surface (main surface B) of the collected sample. (Step 3) Select the fiber species with the smallest average fiber diameter from among the fibers visible in scanning microscope image A. Similarly, select the fiber species with the smallest average fiber diameter from among the fibers visible in scanning microscope image B. (Step 4) If both selected fiber types have the same average fiber diameter, these selected fiber types are judged to be fine fibers. If the two selected fiber types do not have the same average fiber diameter, the fiber type with the smaller average fiber diameter among the selected fiber types is judged to be a fine fiber. (Step 5) Determine the percentage A (unit: %) of the number of fine fibers out of 400 fibers visible in scanning microscope image A, and the percentage B (unit: %) of the number of fine fibers out of 400 fibers visible in optical microscope image B. If the result of comparing the values ​​of fiber ratio A and fiber ratio B is "fiber ratio A < fiber ratio B", then it is determined that the nonwoven fabric constituting the surface material has a structure in which "the proportion of fine fibers in the fibers constituting the other main surface is greater than the proportion of fine fibers in the fibers constituting the other main surface". On the other hand, if "number ratio A ≥ number ratio B", it is determined that the nonwoven fabric constituting the surface material does not have the above-described configuration.

[0044] The percentage of the number of fine fibers in the fibers constituting one main surface of the non-woven fabric is appropriately adjusted so as to realize a surface material in which the adhesive is less likely to bleed out. The percentage of the number of fine fibers is preferably 40% or less, more preferably 30% or less, and most preferably 20% or less. Also, the percentage of the number of fine fibers in the fibers constituting the other main surface of the non-woven fabric is appropriately adjusted so as to realize a surface material in which the adhesive is less likely to bleed out. The percentage of the number of fine fibers is preferably 60% or more, more preferably 70% or more, and most preferably 80% or more.

[0045] Due to having the above-described configuration, the non-woven fabric according to the present invention can effectively prevent the adhesive from passing from one main surface to the other main surface. Therefore, in the surface material according to the present invention, the adhesive is less likely to bleed out.

[0046] Various configurations of the non-woven fabric, such as its thickness and basis weight, should not be particularly limited and can be appropriately adjusted. The thickness of the non-woven fabric can be 0.1 to 5 mm, can be 0.5 to 3 mm, and can be 0.8 to 1.9 mm. Also, the upper limit of the basis weight of the non-woven fabric can be, for example, 1000 g / m 2 and can be 500 g / m 2 and can be 300 g / m 2 and can be 200 g / m 2 and can be 150 g / m 2 and can be. Also, the lower limit of the basis weight is appropriately adjusted so as to obtain a surface material in which the adhesive is less likely to bleed out. For example, it is preferably 50 g / m 2 . In the present invention, the thickness refers to the length in the vertical direction when a compressive load of 20 g / cm 2 is applied to the main surface, and the basis weight refers to the mass per 1 m 2 on the main surface.

[0047] Furthermore, the nonwoven fabric may have a print consisting of pigment and binder on one of its main surfaces. The manner of the print can be adjusted as appropriate, but the print may cover the entire surface of the main surface, or it may be applied to form a pattern on only a portion of the main surface.

[0048] Next, the method for manufacturing the surface material of the present invention will be described. Note that explanations of points that are the same as those described above will be omitted. The method for manufacturing the surface material according to the present invention can be appropriately selected, but as an example, (Step 1) A step to prepare a fiber web made by blending fine fibers and thick fibers. (Step 2) A process to prepare a nonwoven fabric by applying a needle punch treatment to the prepared fiber web from only one main surface side, thereby intertwining and integrating the fine and thick fibers. A method for manufacturing a surface material comprising a nonwoven fabric can be employed.

[0049] The above-described method for manufacturing the surface material may include various secondary processes, such as laminating other components onto the prepared nonwoven fabric, and processing the shape of the nonwoven fabric by punching it out according to the application and manner of use. It may also include a pressure treatment process to smooth the surface of the prepared nonwoven fabric, such as a reliable press treatment. Furthermore, it may include a process for printing on the nonwoven fabric.

[0050] The nonwoven fabric prepared in this manner can be used as a surface material on its own. Alternatively, it may be a surface material formed by laminating other components such as a porous body, film, or foam onto the nonwoven fabric. The lamination method can be selected as appropriate, but for example, methods such as lamination and integration by subjecting the fabric to needle punching or water entanglement treatment, lamination and integration by bonding with a binder, or lamination and integration by melting the heat-fusible fibers of the nonwoven fabric or the constituent resins of other components and then solidifying them can be employed.

[0051] Interior and exterior materials can be manufactured by bonding a prepared surface material to a substrate with an adhesive in between to form a laminate. For example, the interior and exterior materials can be manufactured by subjecting the laminate to a heat molding means, such as by placing it in a heated mold. In this case, the main surface of the nonwoven fabric of the surface material with a smaller proportion of fine fibers faces the substrate.

[0052] The type of base material and adhesive used will be adjusted as appropriate depending on the desired physical properties of the interior and exterior materials. For example, fabrics (nonwoven, woven, or knitted), films, or foams can be used as base materials. High-molecular-weight isocyanate adhesives can also be used. [Examples]

[0053] The present invention will be specifically described below with reference to examples, but these examples are not intended to limit the scope of the present invention.

[0054] (Comparative Example 1) Only the solution-dyed polyester fiber A (hereinafter referred to as fiber A, average fiber diameter: 11.0 μm, fiber length: 51 mm) was fed into a carding machine and opened to form a fiber web. Then, a needle density of 400 needles / m was applied only from one main surface side of the fiber web. 2 The nonwoven fabric was prepared by needle punching.

[0055] (Comparative Example 2) A nonwoven fabric was prepared in the same manner as in Comparative Example 1, except that only solution-dyed polyester fiber B (hereinafter referred to as fiber B, average fiber diameter: 14.3 μm, fiber length: 38 mm) was used instead of fiber A.

[0056] (Comparative Example 3) A nonwoven fabric was prepared in the same manner as in Comparative Example 1, except that only solution-dyed polyester fiber C (hereinafter referred to as fiber C, average fiber diameter: 17.5 μm, fiber length: 38 mm) was used instead of fiber A.

[0057] (Example 1) A fiber mixture consisting of 50% by mass of fiber A and 50% by mass of fiber B was fed into a carding machine to open the fibers and form a fiber web. Then, a needle density of 400 needles / m was applied from only one main surface side of the fiber web. 2 The nonwoven fabric was prepared by needle punching.

[0058] The nonwoven fabric of Example 1 prepared as described above had constituent fibers consisting of fine fibers A and thick fibers B. The proportion of fibers A in the main surface on the opposite side of the needle-punched side (the other main surface) was greater than the proportion of fibers A in the main surface on the side that was needle-punched (one main surface). Furthermore, the proportion of fiber A among the fibers constituting one of the main surfaces was 40%, and the proportion of fiber B was 60%. On the other main surface, the proportion of fiber A among the fibers constituting the other surface was 80%, and the proportion of fiber B was 20%.

[0059] The nonwoven fabrics prepared in Comparative Examples 1-3 and Example 1, as described above, were used as surface materials. In all of these nonwoven fabrics, the constituent fibers were not bonded to the constituent resin (i.e., the resin constituting the constituent fibers). Each surface material (nonwoven fabric) was subjected to the following evaluation method to assess its ability to prevent adhesive seepage. The results, along with the composition of each surface material (nonwoven fabric), are summarized in Table 1.

[0060] (Method for evaluating the adhesive's ability to prevent leakage) A flexible polyurethane sheet containing a fluorescent dye was laminated onto a glass fiber sheet. Next, water was sprayed onto the exposed main surface of the flexible polyurethane sheet, and a laminate was prepared by sequentially laminating another glass fiber sheet and then a surface material onto the main surface where the water had been sprayed. At this time, the main surface with a smaller proportion of fine fibers in the surface material was positioned to face the other glass fiber sheet. The laminate was then subjected to a pair of heated and pressurized rolls, which heated the laminate and applied pressure in its thickness direction. At this time, water and a soft polyurethane sheet reacted to form a polyurethane resin. The polyurethane resin, which had permeated another glass fiber sheet, then acted as an adhesive, bonding the surface material and the other glass fiber sheet together with the adhesive in between. After that, the heated laminate was allowed to cool, thereby manufacturing the interior material. One hour after manufacturing, the exposed main surface of the interior material (the main surface with a higher proportion of fine fibers) derived from the surface material was illuminated with a black light to visually check whether or not polyurethane resin, which is an adhesive, had seeped out onto the surface of the interior material. The following criteria were used for evaluation. The evaluation results are listed in the "Adhesive Leakage Prevention Ability" column in the table. ×: Polyurethane resin had seeped out. ○: No polyurethane resin had leaked out.

[0061] [Table 1]

[0062] From the results of comparing Comparative Examples 1-3 with Example 1, • It comprises a nonwoven fabric containing fine and coarse fibers in its constituent fibers. In the nonwoven fabric, the proportion of fine fibers in the fibers constituting one main surface is greater than the proportion of fine fibers in the fibers constituting the other main surface. It has been found that, by possessing both of these configurations, the surface material according to the present invention is less prone to adhesive seepage.

[0063] (Reference example) In the step of preparing the laminate in the above-described (method for evaluating the adhesive's ability to prevent seepage), the main surface of the surface material prepared in Example 1 with a higher proportion of fine fibers was made to face another glass fiber sheet. Using the laminate prepared in this way, an interior material was manufactured in the same manner as described above. One hour after manufacturing, the exposed main surface of the interior material (the main surface with a lower proportion of fine fibers) derived from the surface material was illuminated with a black light to visually check whether or not polyurethane resin, which is an adhesive, had seeped out onto the surface of the interior material. Upon inspection, it was found that polyurethane resin had leaked out.

[0064] From a comparison of Example 1 and the Reference Example, it was found that in an interior and exterior material in which a base material and a surface material are bonded together with an adhesive in between, when the main surface of the nonwoven fabric that is bonded to the base material is the main surface with a lower proportion of fine fibers, the leakage of the adhesive is prevented.

[0065] (Examples 2-4) Various nonwoven fabrics were prepared in the same manner as in Example 1, except that the basis weight was changed by varying the amount of fiber group formed by the blending of fiber A and fiber B that was fed to the carding machine, as shown in Table 2.

[0066] The nonwoven fabrics prepared in Examples 2 to 4 as described above consisted of fine fibers A and thick fibers B, and the proportion of fibers A in the main surface on the opposite side of the needle-punched side (the other main surface) was greater than the proportion of fibers A in the main surface on the side of the needle-punched side (the other main surface). In all of the nonwoven fabrics prepared in Examples 2 to 4, the proportion of fiber A in the fibers constituting one main surface was 40%, and the proportion of fiber B was 60%. Furthermore, the proportion of fiber A in the fibers constituting the other main surface was 80%, and the proportion of fiber B was 20%.

[0067] The nonwoven fabrics prepared in Examples 2 to 4, as described above, were used as surface materials. In all of these nonwoven fabrics, the constituent fibers were not bonded to the constituent resin (i.e., the resin constituting the constituent fibers). The adhesive leakage prevention ability of each surface material (nonwoven fabric) was evaluated and summarized in Table 2 along with the composition of each surface material (nonwoven fabric). For ease of understanding, the results of Example 1 are also included in Table 2.

[0068] [Table 2]

[0069] From the results of Examples 1 to 4, it was found that the surface material according to the present invention is less prone to adhesive seepage due to having both of the above-described configurations. In addition, it was found that the adhesive is less prone to seepage even when the weight is light and the thickness is thin.

[0070] (Example 5) A fiber mixture consisting of 70% by mass of fiber B and 30% by mass of fiber C was fed into a carding machine to open the fibers and form a fiber web. Then, a needle density of 400 needles / m was applied from only one main surface side of the fiber web. 2 The nonwoven fabric was prepared by needle punching.

[0071] The nonwoven fabric of Example 5 prepared as described above had constituent fibers consisting of fine fibers B and thick fibers C. The proportion of fibers B in the main surface on the opposite side of the needle-punched surface (the other main surface) was greater than the proportion of fibers B in the main surface on the side of the needle-punched surface (the other main surface). Furthermore, the proportion of fiber B among the fibers constituting one of the main surfaces was 70%, and the proportion of fiber C was 30%. On the other main surface, the proportion of fiber B among the fibers constituting the other surface was 85%, and the proportion of fiber C was 15%.

[0072] (Examples 6-7) Various nonwoven fabrics were prepared in the same manner as in Example 5, except that the basis weight was changed by varying the amount of fiber group formed by the blending of fiber B and fiber C to be fed into the carding machine, as shown in Table 3.

[0073] The nonwoven fabrics prepared in Examples 6-7 as described above consisted of fine fibers B and thick fibers C, and the proportion of fibers B in the main surface on the opposite side of the needle-punched surface (the other main surface) was greater than the proportion of fibers B in the main surface on the side of the needle-punched surface (one main surface). In the nonwoven fabrics prepared in Examples 6 and 7, the proportion of fiber B in the fibers constituting one main surface was 70%, and the proportion of fiber C was 30%. On the other main surface, the proportion of fiber B in the fibers constituting the other main surface was 85%, and the proportion of fiber C was 15%.

[0074] The nonwoven fabrics prepared in Examples 5 to 7, as described above, were used as surface materials. In all of these nonwoven fabrics, the constituent fibers were not bonded to the constituent resin (i.e., the resin constituting the constituent fibers). The adhesive leakage prevention ability of each surface material (nonwoven fabric) was evaluated and summarized in Table 3 along with the composition of each surface material (nonwoven fabric).

[0075] [Table 3]

[0076] The results from Examples 5 to 7 show that, by possessing both of the above-described configurations of the present invention, the surface material according to the present invention is less prone to adhesive seepage. In addition, it was found that even when the weight is light and the thickness is thin, the adhesive is less prone to seepage. [Industrial applicability]

[0077] The surface material of the present invention can be suitably used for automotive applications such as ceilings, door sides, pillar garnishes, and rear packages; for interior applications such as partitions; and for building materials such as wall coverings.

Claims

1. A surface material comprising a nonwoven fabric containing a first fiber having the smallest average fiber diameter and a second fiber having a larger average fiber diameter than the first fiber, In the nonwoven fabric, the proportion of the first fibers in the fibers constituting the main surface opposite to the first main surface is greater than the proportion of the first fibers in the fibers constituting the main surface of the main surface of the main surface of the main surface of the main fabric. Surface material.

2. The surface material according to claim 1, wherein the constituent fibers are not bonded to the constituent resin.

3. A surface material that is bonded to a substrate via an adhesive in between, The surface material comprises a nonwoven fabric containing a first fiber having the smallest average fiber diameter among its constituent fibers and a second fiber having a larger average fiber diameter than the first fiber. In the nonwoven fabric, the proportion of the first fibers in the main surface on the side opposite to the side that is bonded to the substrate is greater than the proportion of the first fibers in the main surface on the side that is bonded to the substrate. Surface material.

4. An interior and exterior material in which a base material and a surface material according to any one of claims 1 to 3 are bonded together with an adhesive in between, In the nonwoven fabric, the main surface that is in contact with the substrate is the main surface with a smaller proportion of the first fibers. Interior and exterior materials.

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