Mat material, exhaust gas purification device, and method for manufacturing mat material

Abstract

Provided is a mat material wherein, on at least one of first and second principal surfaces of a base material mat containing inorganic fibers and having the first and second principal surfaces, a network is formed by a plurality of base parts made up of organic matter and fibers extending in at least two directions from each of the plurality of base parts.

Description

Mat material, exhaust gas purification device, and method for manufacturing the mat material

[0001] The present invention relates to a mat material, an exhaust gas purification device, and a method for manufacturing the mat material.

[0002] Particulate matter (hereinafter referred to as PM) is contained in exhaust gases emitted from internal combustion engines such as diesel engines, and in recent years, the harm that this PM poses to the environment and human health has become a problem. Furthermore, because exhaust gases also contain harmful gas components such as CO, HC, and NOx, there are concerns about the impact that these harmful gas components have on the environment and human health.

[0003] Therefore, various exhaust gas purification devices have been proposed that capture PM in exhaust gas and purify harmful gas components, and are composed of an exhaust gas treatment body made of porous ceramics such as silicon carbide or cordierite, a casing (cylindrical member) that houses the exhaust gas treatment body, and a holding seal material disposed between the exhaust gas treatment body and the casing. The holding seal material is disposed mainly for the purposes of preventing the exhaust gas treatment body from coming into contact with the casing that surrounds it and being damaged by vibrations and impacts caused by the running of the automobile, and preventing exhaust gas from leaking from between the exhaust gas treatment body and the casing.

[0004] As a holding sealing material for such applications, a mat material made of inorganic fibers is used. The mat material made of inorganic fibers is also used for heat insulation and soundproofing by wrapping it around piping in automobiles, etc.

[0005] Patent Document 1 discloses a holding seal material in which a sheet material having an opening in at least a part of its surface is placed on at least one of the first and second main surfaces of a base material. It also discloses that the sheet material made of a heat-sealing material is bonded to the main surface of the base material by thermocompression bonding the sheet material to the base material without using an adhesive.

[0006] JP 2009-85092 A

[0007] In Patent Document 1, the sheet material is provided to prevent inorganic fibers contained in the base material from scattering.

[0008] A conventional method for manufacturing such mat materials is to punch them out using a punching die with a punching blade (also called punching processing). In this process, a large-sized adhesive body is prepared by attaching a sheet-like member made of inorganic fiber and a flexible sheet, and by punching this adhesive body, a large number of mat materials can be obtained in a single punching process.

[0009] The mat material has a longitudinal direction, which is the wrapping direction, and a lateral direction, which is perpendicular to the longitudinal direction. When obtaining such a mat material from a single large-sized adhesive body, a combination of punching locations where the mat material is punched in the direction where the vertical direction of the adhesive body is the longitudinal direction of the mat material and punching locations where the horizontal direction of the adhesive body is the longitudinal direction of the mat material is used is used to obtain as much mat material as possible from a single large-sized adhesive body. In this case, two types of mat material are obtained, each with a different relationship between the longitudinal and horizontal directions of the adhesive body and the longitudinal direction of the mat material.

[0010] In addition, in Patent Document 1, the sheet material is fixed to the base material by thermocompression bonding, and during this process, the fibers forming the sheet material themselves melt and are attached to the base material. Therefore, it is thought that holes are formed in the fibers of the sheet material after thermocompression bonding, reducing the fiber strength. Furthermore, it is thought that the fusion of multiple fibers in the sheet material to each other reduces the flexibility of the sheet material. As a result, there is a risk of cracking of the mat material when the mat material provided with the sheet material is wrapped around an exhaust gas treatment body or the like.

[0011] The present invention has been made in view of the above problems, and has an object to provide a mat material that can suppress the occurrence of cracks during winding.

[0012] The mat material according to a first aspect of the present invention is characterized in that a base mat contains inorganic fibers and has first and second main surfaces, and a network is formed on at least one of the first and second main surfaces by a plurality of bases made of an organic substance and fibers extending in at least two directions from each of the plurality of bases.

[0013] The mat material according to the first aspect of the present invention has a network formed on at least one of the first and second main surfaces of the substrate mat, the network being made up of a plurality of bases made of organic matter and fibers extending in at least two directions from each of the plurality of bases. As a result, the mat material has high strength and flexibility, and is therefore able to suppress cracks when wrapped around the mat material.

[0014] In the mat material according to the first aspect of the present invention, the maximum width of each of the plurality of bases is preferably greater than the width of the fibers forming the network. This allows a greater number of fibers forming the network to be firmly bonded together, thereby further improving the strength of the entire mat material. As a result, the occurrence of cracks during winding of the mat material can be more effectively suppressed.

[0015] In the mat member according to the first aspect of the present invention, the glass transition temperature of the fibers forming the network is preferably higher than the glass transition temperature of the organic material forming the plurality of bases, which makes it possible to easily form the network using a hot melt powder.

[0016] In the mat material according to the first aspect of the present invention, the network is preferably formed three-dimensionally, which can improve the strength of the network formed on the first and / or second main surfaces of the substrate mat and disperse stress applied to the network, thereby more effectively suppressing cracks during wrapping of the mat material.

[0017] In the mat material according to the first aspect of the present invention, the fibers forming the network are preferably at least one of organic fibers and inorganic fibers, and from the viewpoint of more effectively suppressing cracks during wrapping of the mat material, the fibers forming the network are preferably organic fibers.

[0018] A mat material according to a second aspect of the present invention is characterized in that a base mat contains inorganic fibers and has first and second main surfaces, and a web is formed on at least one of the first and second main surfaces by fiber bundles formed by intertwining a plurality of fibers and single fibers.

[0019] In the mat material according to the second aspect of the present invention, the web contains fiber bundles, which are formed by intertwining a plurality of fibers, and the web is formed from such fiber bundles and short fibers, which can prevent a decrease in the strength and flexibility of the fibers forming the web, thereby preventing cracks from occurring when the mat material is wound.

[0020] The mat material according to the second aspect of the present invention preferably includes a plurality of the fiber bundles having different stretching directions, and the web is formed from the plurality of the fiber bundles and the single fibers, thereby making it possible to make the number of longitudinally oriented fibers and the number of transversely oriented fibers approximately the same.

[0021] In the mat material according to the second aspect of the present invention, it is preferable that at least one of the fiber bundles and the single fibers is curved, which increases the number of intersections between the fibers forming the web and disperses stress applied to the web, thereby more effectively suppressing cracks when the mat material is wound.

[0022] In the mat member according to the second aspect of the present invention, the web is preferably formed three-dimensionally, which can improve the strength of the web formed on the first and / or second main surfaces of the base mat and can distribute stress applied to the web, thereby more effectively suppressing cracks when the mat member is wrapped around the base mat.

[0023] In the mat material according to the second aspect of the present invention, the fiber bundles and the monofilaments are preferably each made of at least one of organic fibers and inorganic fibers, from the viewpoint of more effectively suppressing cracks during winding of the mat material.

[0024] The exhaust gas purification device of the present invention is an exhaust gas purification device comprising an exhaust gas treatment body through which exhaust gas flows, a holding sealing material that is wrapped around the outer periphery of the exhaust gas treatment body, and a casing that houses the exhaust gas treatment body around which the holding sealing material is wrapped, and is characterized in that the holding sealing material is a mat material according to the first or second aspect of the present invention.

[0025] As described above, the mat material according to the first and second aspects of the present invention can suppress the occurrence of cracks during winding, and therefore the exhaust gas purification device of the present invention can suppress the leakage of untreated exhaust gas through cracks in the mat material.

[0026] The method for manufacturing a mat material of the present invention is characterized by comprising: a substrate mat preparation step of preparing a substrate mat containing inorganic fibers and having first and second main surfaces; a sheet material preparation step of preparing a sheet material containing fibers extending in at least two directions; a sheet material processing step of spraying hot melt powder onto the sheet material, heating it, and adhering the hot melt powder to the sheet material; and a sheet material attachment step of thermocompression-bonding the sheet material with the hot melt powder adhered to at least one of the first and second main surfaces of the substrate mat, and attaching the sheet material to the substrate mat.

[0027] In the method for manufacturing a mat material of the present invention, a hot melt powder is sprayed onto a sheet material containing fibers extending in at least two directions, the hot melt powder is then heated, the hot melt powder is adhered to the sheet material, and the sheet material with the hot melt powder adhered thereto is thermocompressed to at least one of the first and second main surfaces of the base mat, thereby adhering the sheet material to the base mat. This allows the sheet material to be attached to the base mat while preventing the fibers forming the sheet material from melting. This prevents a decrease in the strength and flexibility of the fibers forming the sheet material. Furthermore, by heating and melting the hot melt powder, a network having bases can be formed. As a result, the occurrence of cracks during wrapping of the mat material can be suppressed.

[0028] FIG. 1 is a perspective view schematically showing an example of a mat material according to a first embodiment of the present invention. FIG. 2 is an enlarged plan view schematically showing the network shown in FIG. 1. FIG. 3 is a perspective view schematically showing an example of an adhesive body. FIG. 4 is a top view schematically showing an example of a process for obtaining two types of mat materials by punching. FIG. 5 is a perspective view schematically showing an example of a mat material according to a second embodiment of the present invention. FIG. 6 is an enlarged plan view schematically showing the web shown in FIG. 5. FIG. 7 is a perspective view schematically showing another example of an adhesive body. FIG. 8 is a top view schematically showing another example of a process for obtaining two types of mat materials by punching. FIG. 9 is a cross-sectional view schematically showing an example of an exhaust gas purification device according to the present invention. FIG. 10 is a photograph of the mat material of Comparative Example 1.

[0029] (Detailed Description of the Invention) The mat material, exhaust gas purification device, and method for manufacturing the mat material of the present invention will be specifically described below. However, the present invention is not limited to the following configurations, and can be appropriately modified and applied within the scope that does not change the gist of the present invention. Note that a combination of two or more of the individual preferred configurations of the present invention described below also constitutes the present invention.

[0030] The mat material according to a first aspect of the present invention is characterized in that a base mat contains inorganic fibers and has first and second main surfaces, and a network is formed on at least one of the first and second main surfaces by a plurality of bases made of an organic substance and fibers extending in at least two directions from each of the plurality of bases.

[0031] FIG. 1 is a perspective view schematically illustrating an example of a mat material according to a first embodiment of the present invention. The mat material 10 shown in FIG. 1 has a structure in which a base material mat 20 having a first main surface 21 and a second main surface 22 has a network 70 formed on the first main surface 21, the network 70 being made of an organic base and fibers (both not shown in FIG. 1 ). Of the ends of the mat material 10 in the longitudinal direction (the direction indicated by the double-headed arrow L in FIG. 1 ), one end, i.e., a first end, has a convex portion 11, and the other end, i.e., a second end, has a concave portion 12. The convex portions 11 and the concave portions 12 are formed by overlapping the convex portions and concave portions provided on the base material mat 20 and the network 70, respectively. The convex portions and concave portions of the mat material are shaped to fit together when the mat material is wrapped around an exhaust gas purification device, an exhaust gas treatment body, or an exhaust pipe having a cylindrical outer periphery. In FIG. 1, the direction indicated by the double-headed arrow W is the widthwise direction of the mat material, and the direction indicated by the double-headed arrow T is the thickness direction of the mat material.

[0032] 1 shows the case where the network 70 is formed only on the first main surface 21 of the base mat 20, but the network 70 may be formed on each of the first main surface 21 and the second main surface 22 of the base mat 20. Furthermore, the network 70 may be formed on the side surface of the base mat 20 in addition to the first main surface 21 and / or the second main surface 22 of the base mat 20.

[0033] Fig. 2 is an enlarged plan view schematically showing the network shown in Fig. 1. In Fig. 2, the base mat 20 is also shown by a dashed line to show the positional relationship between the network 70 and the base mat 20. As shown in Fig. 2, the network 70 is formed of a plurality of bases 71 made of an organic material and fibers 72 extending in two directions from each of the plurality of bases 71. Such a network 70 has high strength and flexibility, and therefore can suppress the occurrence of cracks when the mat material 10 is wrapped around it.

[0034] Here, the fibers 72 include longitudinally oriented fibers 31 and laterally oriented fibers 32 that extend in two directions, the longitudinal direction and the transverse direction, respectively. The longitudinally oriented fibers 31 are oriented in the longitudinal direction, which is approximately parallel to the longitudinal direction of the mat material 10 (the direction indicated by the double-headed arrow L in FIG. 1 ). The laterally oriented fibers 32 are oriented in the transverse direction, which is approximately parallel to the transverse direction of the mat material 10 (the direction indicated by the double-headed arrow W in FIG. 1 ). Here, the direction in which the length directions of the fibers constituting the longitudinally oriented fibers 31 are aligned is the orientation direction of the longitudinally oriented fibers 31, and the direction in which the length directions of the fibers constituting the transversely oriented fibers 32 are aligned is the orientation direction of the transversely oriented fibers 32. The longitudinally oriented fibers 31, whose fibers are oriented (aligned) in the longitudinal direction, and the transversely oriented fibers 32, whose fibers are oriented (aligned) in the transverse direction, are layered to form a nonwoven fabric with longitudinal and transverse fiber orientations.

[0035] The nonwoven fabric made of fibers 72 is produced using a manufacturing process in which raw materials are directly spun into yarn, and the spun fibers are stretched in both the vertical and horizontal directions to orient the long fiber filaments in both the vertical and horizontal directions. The nonwoven fabric made of fibers 72 is an openwork nonwoven fabric, and has openings surrounded by vertically oriented fibers 31 and horizontally oriented fibers 32.

[0036] 2 shows a case where one layer of each of the longitudinally oriented fibers 31 and the transversely oriented fibers 32 is laminated, there is no particular limitation on the number of layers of the longitudinally oriented fibers 31 and the transversely oriented fibers 32, and three or more layers of the longitudinally oriented fibers 31 and the transversely oriented fibers 32 may be laminated alternately. Furthermore, there is no particular limitation on the order in which the longitudinally oriented fibers 31 and the transversely oriented fibers 32 are laminated.

[0037] Furthermore, the network 70 may contain fibers extending in three or more directions, for example, it may contain fibers extending in an oblique direction in addition to the longitudinally oriented fibers 31 and the transversely oriented fibers 32 .

[0038] Furthermore, the relationship between the orientation directions of the vertically oriented fibers 31 and the horizontally oriented fibers 32 and the longitudinal and short directions of the mat material 10 is not particularly limited, but it is preferable that one of the orientation directions of the vertically oriented fibers 31 and the horizontally oriented fibers 32 is parallel to the longitudinal direction of the mat material 10, and the other orientation direction of the vertically oriented fibers 31 and the horizontally oriented fibers 32 is parallel to the short direction of the mat material 10.

[0039] The bases 71 are distributed within the network 70, and unlike the fibers 72 that extend one-dimensionally, each base 71 extends in the longitudinal direction, lateral direction, and thickness direction (particularly the longitudinal direction and lateral direction) of the mat material 10. The bases 71 are fused together to bond the fibers 72 that extend in different directions to each other. That is, the bases 71 are arranged in the regions where the longitudinally oriented fibers 31 and the laterally oriented fibers 32 intersect, and bond these fibers to each other.

[0040] Thus, from the viewpoint of bonding more fibers 72 forming the network 70 together more firmly, it is preferable that the maximum width of each base 71 be larger than the width of the fibers 72. As a result, the occurrence of cracks when the mat material 10 is wrapped around the mat material 10 can be more effectively suppressed. For example, the base 71 may be large enough to occupy at least a portion of the area where multiple longitudinally oriented fibers 31 and multiple laterally oriented fibers 32 intersect, but it is more preferable that one base 71 include multiple areas where the longitudinally oriented fibers 31 and laterally oriented fibers 32 intersect. Note that it is preferable to compare the maximum width of each base 71 with the width of the fibers 72 when the network 70 is viewed in plan.

[0041] The base 71 also serves to fix the network 70 to the base mat 20. That is, the base 71 bonds the fibers 72 that form the network 70 to the base mat 20 by fusing.

[0042] As described above, the network 70 is formed by a nonwoven fabric in which fibers 72 oriented in multiple directions (e.g., vertically oriented fibers 31 and horizontally oriented fibers 32) are laminated, and a base 71 distributed on the nonwoven fabric and joining fibers 72 of different orientation directions (e.g., vertically oriented fibers 31 and horizontally oriented fibers 32) located in different layers.

[0043] In this way, the network 70 is formed three-dimensionally. That is, the network 70 extends in the longitudinal and lateral directions of the mat material 10 and has a thickness in the thickness direction of the mat material 10. This further improves the strength of the network 70 and distributes the stress applied to the network 70, making it possible to more effectively suppress the occurrence of cracks when the mat material 10 is wrapped around it.

[0044] 2 shows a case where the network 70 includes fiber bundles formed by entanglement of a plurality of fibers and single fibers, the network 70 may be formed only from fiber bundles or only from single fibers. Details of these configurations will be described below.

[0045] The substrate mat constituting the mat material according to the first aspect of the present invention is made of inorganic fibers. The inorganic fibers are not particularly limited and may be alumina-silica fibers, alumina fibers, silica fibers, etc. Glass fibers or biosoluble fibers may also be used. The inorganic fibers may be changed depending on the properties required of the mat material, such as heat resistance and wind erosion resistance, and it is preferable to use fibers with a large diameter and fiber length that comply with the environmental regulations of each country.

[0046] Among these, inorganic fibers of low crystalline alumina are preferred, inorganic fibers of low crystalline alumina having a mullite composition are more preferred, and inorganic fibers containing a spinel compound are even more preferred.

[0047] The substrate mat has a longitudinal direction, which is the wrapping direction, and a lateral direction perpendicular to the longitudinal direction. It is preferable that the substrate mat has a convex portion formed at one of the longitudinal ends, i.e., a first end, and a concave portion formed at the other end, i.e., a second end. It is preferable that the convex portion and the concave portion of the substrate mat are shaped so that they fit together perfectly when the mat material is wrapped around an exhaust gas purification device, an exhaust gas treatment body, or an exhaust pipe, which has a cylindrical outer periphery. Alternatively, the substrate mat may have a shape in which no convex portion or concave portion is formed.

[0048] The thickness of the base mat is preferably 2 to 30 mm. If the thickness of the base mat is less than 2 mm, the thickness is too thin, resulting in reduced thermal insulation and soundproofing performance. On the other hand, if the thickness of the base mat exceeds 30 mm, the flexibility decreases, resulting in reduced attachment to the component to which it is attached.

[0049] The bulk density of the base mat is not particularly limited, but is preferably 0.05 to 0.30 g / cm ３ It is preferable that the bulk density of the base mat is 0.05 g / cm ３ If the bulk density of the base mat is less than 0.30 g / cm, the entanglement of the inorganic fibers is weak and the inorganic fibers are easily peeled off, making it difficult to maintain the desired shape of the base mat. ３ If the hardness exceeds 100%, the base mat becomes hard, the attachability to the member to be attached decreases, and the base mat becomes more likely to crack.

[0050] At least one of the first and second main surfaces of the substrate mat constituting the mat material according to the first aspect of the present invention has a network formed thereon consisting of a plurality of bases made of organic matter and fibers extending in at least two directions from each of the plurality of bases.

[0051] The organic material constituting the base is different from the material of the fibers that form the network (hereinafter referred to as network fibers). Specifically, the base is formed by thermally fusing hot melt powder (hot melt adhesive) to the network fibers.

[0052] Therefore, it is preferable that the glass transition temperature Tg1 of the network fiber is higher than the glass transition temperature Tg2 of the organic material constituting the base. This makes it possible to easily form a network having a base using a hot melt powder.

[0053] The glass transition point Tg1 of the network fiber is not particularly limited, but is preferably −140° C. or higher and 90° C. or lower, and more preferably −130° C. or higher and 80° C. or lower. The glass transition point Tg2 of the organic material constituting the base is also not particularly limited, but is preferably −140° C. or higher and 90° C. or lower, and more preferably −130° C. or higher and 80° C. or lower. Furthermore, the difference between the glass transition point Tg1 of the network fiber and the glass transition point Tg2 of the organic material constituting the base, i.e., (Tg1−Tg2), is not particularly limited, but is preferably 220° C. or lower, and more preferably 200° C. or lower in order to integrate the network fiber and the base.

[0054] The organic material constituting the base is not particularly limited as long as it can be used as a hot melt powder, and specific examples include polyethylene (PE), polyethylene terephthalate (PET), polyamide (PA), ethylene-vinyl acetate copolymer resin (EVA), etc.

[0055] The network fibers are preferably long fiber filaments. The long fiber filaments are preferably fibers longer than ordinary short fiber fibers (e.g., 10 to 50 mm), and the average fiber length of the filaments is preferably longer than 100 mm, and more preferably the average fiber length of the filaments is several hundred mm or more. The long fiber filaments may be continuous long fibers.

[0056] The average fiber diameter of the main constituent filaments of the network fibers is usually 10 μm or less, and preferably around 5 μm.

[0057] The network preferably has substantially the same planar shape as the base mat. That is, the arrangement areas of the network and the base mat preferably substantially coincide in a plan view. Furthermore, it is preferable that a sheet material composed of the network is formed and attached to the base mat. The sheet material and the base mat are preferably attached via hot melt powder.

[0058] The basis weight of the sheet material made of the network is not particularly limited, but is preferably 5 g / m ２ Above, 100g / m ２ Preferably, it is 5 g / m or less. ２ Above, 50g / m ２ More preferably, it is 5 g / m or less. ２ Above, 30g / m ２ It is more preferable that the basis weight of the sheet material mentioned here is the basis weight per sheet of the sheet material.

[0059] The network fibers are preferably composed of at least one of organic fibers and inorganic fibers. For example, the longitudinally oriented fibers may be composed of organic fibers and / or inorganic fibers, and the transversely oriented fibers may be composed of organic fibers and / or inorganic fibers. The longitudinally oriented fibers and the transversely oriented fibers may be made of different materials, but typically, when the longitudinally oriented fibers are composed of organic fibers, the transversely oriented fibers are also made of organic fibers, and when the longitudinally oriented fibers are composed of inorganic fibers, the transversely oriented fibers are also made of inorganic fibers.

[0060] The network fibers are preferably organic fibers, which can more effectively prevent cracks from occurring when the mat material is wound around the mat material. For example, both the longitudinally oriented fibers and the transversely oriented fibers may be organic fibers.

[0061] More specifically, suitable materials for the network fibers include polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), and the like.

[0062] In the mat material according to the first aspect of the present invention, the base mat preferably further includes at least one of an inorganic binder and an organic binder. The amount of the inorganic binder used (weight of the inorganic binder / weight of the mat material) may be, for example, more than 0 wt % and not more than 15 wt %. The amount of the organic binder used (weight of the organic binder / weight of the mat material) may be, for example, more than 0 wt % and not more than 15 wt %.

[0063] As the inorganic binder, alumina sol, silica sol, etc. can be used.

[0064] As the organic binder, it is preferable to use water-soluble organic polymers such as acrylic resin, acrylate latex, rubber latex, carboxymethyl cellulose or polyvinyl alcohol, thermoplastic resins such as styrene resin, thermosetting resins such as epoxy resin, etc.

[0065] Next, a method for manufacturing a mat material according to a first aspect of the present invention will be described. The method for manufacturing a mat material according to the first aspect of the present invention includes a substrate mat preparation step of preparing a substrate mat containing inorganic fibers and having first and second main surfaces, a sheet material preparation step of preparing a sheet material containing fibers extending in at least two directions, a sheet material processing step of spraying hot melt powder on the sheet material and heating it to cause the hot melt powder to adhere to the sheet material, and a sheet material attachment step of thermocompression-bonding the sheet material with the hot melt powder adhered to at least one of the first and second main surfaces of the substrate mat to attach the sheet material to the substrate mat.

[0066] In the method for producing a mat material of the present invention, it is preferable to produce two types of mat materials, a first mat material and a second mat material, both of which are the mat materials according to the first aspect of the present invention.

[0067] In the method for manufacturing a mat member of the present invention, first, a substrate mat having first and second main surfaces and a sheet member containing fibers extending in at least two directions are prepared. The structure and physical properties of the substrate mat prepared here are the same as those of the substrate mat described in the mat member according to the first aspect of the present invention, and therefore a detailed description thereof will be omitted. Furthermore, the structure and physical properties of the sheet member prepared here are the same as those of the network described in the mat member according to the first aspect of the present invention, except that it does not have a base portion, and therefore a detailed description thereof will be omitted. However, the substrate mat and sheet member prepared here are preferably large sheets that can be punched to obtain a large number of mat members according to the first aspect of the present invention.

[0068] The substrate mat can be obtained by various methods, for example, by a papermaking method or a needling method. In the case of the papermaking method, it can be produced, for example, by the following method. Inorganic fibers are opened and dispersed in a solvent to form a mixed solution. The mixed solution is poured into a molding machine with a filtration mesh formed on the bottom surface, and the solvent in the mixed solution is removed to obtain an inorganic fiber aggregate. The inorganic fiber aggregate is then dried to obtain a substrate mat. In the case of the needling method, it can be produced, for example, by the following method. A spinning mixture made from a basic aluminum chloride aqueous solution and silica sol, etc., is spun by a blowing method to produce an inorganic fiber precursor having an average fiber diameter of 3 to 10 μm. Next, the inorganic fiber precursor is compressed to produce a continuous substrate mat of a predetermined size, and the substrate mat can be obtained by subjecting it to a calcination treatment. A needle-punching treatment is performed either before or after this calcination treatment to entangle the inorganic fibers.

[0069] The sheet material can be produced, for example, by the following method. First, a raw material (e.g., a resin) is melt-spun using a nonwoven fabric spinning device such as a melt-blown nonwoven fabric or a spunbond nonwoven fabric. Next, fibers are aligned in both the machine direction (MD) and the cross direction (CD) and stretched to produce a longitudinally stretched web in which a continuous body of long fiber filaments is stretched in the machine direction, and a transversely stretched web in which a continuous body of the same long fiber filaments is stretched in the transverse direction. The machine-stretched web and the transversely stretched web are then laminated and bonded to produce a laminated sheet material (nonwoven fabric) in which machine-oriented fibers and transversely oriented fibers are laminated. Examples of methods that can be used to bond the machine-stretched web and the transversely stretched web include water jetting, needle punching, through-air welding, thermal embossing, adhesive bonding, stitch bonding, ultrasonic sealing, and induction heating sealing.

[0070] Next, hot melt powder (powdered hot melt adhesive) is sprinkled on the sheet material and heated to adhere the hot melt powder to the sheet material. The heating temperature and heating time are not particularly limited and can be set appropriately depending on the properties of the hot melt powder.

[0071] Next, the sheet material with the hot melt powder attached thereto is thermocompression bonded to at least one of the first and second main surfaces of the base mat, and the sheet material is attached to the base mat. At this time, it is preferable to attach a large-sized sheet material to a large-sized base mat to obtain an attached body. The thermocompression bonding conditions are not particularly limited and can be set appropriately depending on the characteristics of the hot melt powder. The heating temperature is preferably 115°C or higher and 140°C or lower, more preferably 120°C or higher and 130°C or lower, and the heating time is preferably 25 seconds or higher and 60 seconds or lower, more preferably 30 seconds or higher and 50 seconds or lower.

[0072] 3 is a perspective view showing a schematic example of an adhesive body. The adhesive body 150 is a rectangular sheet having two vertical sides and two horizontal sides, with a large sheet material 130 attached to a first main surface 121 of a large base mat 120. The sheet material 130 is a laminate of vertically oriented fibers and horizontally oriented fibers, with the orientation direction of the vertically oriented fibers of the sheet material 130 being vertical and parallel to the two vertical sides of the adhesive body 150, and the orientation direction of the horizontally oriented fibers of the sheet material 130 being horizontal and parallel to the two horizontal sides of the adhesive body 150.

[0073] Subsequently, the adhesive body is subjected to a punching process, whereby a mat member having a predetermined shape can be produced.

[0074] In the method for manufacturing a mat material of the present invention, a hot melt powder is sprayed onto a sheet material containing fibers extending in at least two directions, the sheet material is heated, the hot melt powder is adhered to the sheet material, and the sheet material with the adhered hot melt powder is thermocompression-bonded to at least one of the first and second main surfaces of a base mat, thereby adhering the sheet material to the base mat. This allows the sheet material to be attached to the base mat while preventing the fibers forming the sheet material, i.e., the network fibers themselves, from melting. This prevents a decrease in the strength and flexibility of the network fibers. Furthermore, by heating and melting the hot melt powder, a network having a base can be formed. As a result, the occurrence of cracks during wrapping of the mat material can be suppressed.

[0075] In the punching process of the adhesive body, it is preferable to carry out a process of obtaining a first mat material in which the vertical direction of the adhesive body is the longitudinal direction of the mat material and the horizontal direction of the adhesive body is the short side direction of the mat material, and a second mat material in which the horizontal direction of the adhesive body is the longitudinal direction of the mat material and the vertical direction of the adhesive body is the short side direction of the mat material, thereby obtaining two types of mat material, the first mat material and the second mat material.

[0076] FIG. 4 is a top view schematically illustrating an example of a process for obtaining two types of mat materials by punching. Punching is performed on the adhesive body 150 shown in FIG. 4 to obtain two types of mat materials. The left side of FIG. 4 shows the production of a first mat material 1 in which the orientation direction of the longitudinally oriented fibers of the sheet material (the longitudinal direction shown in FIG. 4 ) is the longitudinal direction of the mat material, and the orientation direction of the transversely oriented fibers of the sheet material (the transverse direction shown in FIG. 4 ) is the short-side direction of the mat material. The right side of FIG. 4 shows the production of a second mat material 2 in which the orientation direction of the transversely oriented fibers of the sheet material (the transverse direction shown in FIG. 4 ) is the longitudinal direction of the mat material, and the orientation direction of the longitudinally oriented fibers of the sheet material (the longitudinal direction shown in FIG. 4 ) is the short-side direction of the mat material.

[0077] In the first mat material 1 and the second mat material 2, the number and density of the fibers of the sheet material oriented in the longitudinal direction of the mat material (longitudinal or horizontally oriented fibers) and the number and density of the fibers of the sheet material oriented in the short direction of the mat material (horizontal or vertically oriented fibers) are the same, so they exhibit approximately the same tensile strength and windability.

[0078] In addition, in the punching process, it is preferable that the orientation direction of one of the longitudinally oriented fibers and the transversely oriented fibers of the sheet material is parallel to the longitudinal direction of the first mat material and parallel to the short direction of the second mat material. It is also preferable that the orientation direction of the other of the longitudinally oriented fibers and the transversely oriented fibers of the sheet material is parallel to the short direction of the first mat material and parallel to the longitudinal direction of the second mat material. The punching direction shown in Figure 4 is a direction that satisfies the above conditions.

[0079] In addition, although the method for manufacturing the mat material of the present invention has been described as using a sheet material containing fibers extending in at least two directions, the mat material of the first aspect of the present invention can also be manufactured without using such a sheet material.

[0080] For example, fibers stretched in different directions may be sequentially laminated on at least one of the first and second main surfaces of the base mat using a hot melt powder. More specifically, first, longitudinally oriented fibers (longitudinal stretched web) may be thermocompressed onto at least one of the first and second main surfaces of the base mat using a hot melt powder, and then transversely oriented fibers (transversely stretched web) may be thermocompressed onto the longitudinally oriented fibers using a hot melt powder.

[0081] Next, a mat material according to a second aspect of the present invention will be described. The mat material according to the second aspect of the present invention is characterized in that a base mat containing inorganic fibers has first and second main surfaces, and a web is formed on at least one of the first and second main surfaces by fiber bundles formed by entanglement of a plurality of fibers and monofilaments.

[0082] FIG. 5 is a perspective view schematically illustrating an example of a mat material according to a second embodiment of the present invention. The mat material 210 shown in FIG. 5 has a structure in which a substrate mat 220 having a first main surface 221 and a second main surface 222 has a web 270 formed on the first main surface 221, the web 270 being composed of fiber bundles and monofilaments (both not shown in FIG. 5 ). Of the longitudinal ends of the mat material 210 (the direction indicated by the double-headed arrow L in FIG. 5 ), a convex portion 211 is formed on one end, i.e., a first end, and a concave portion 212 is formed on the other end, i.e., a second end. The convex portion 211 and the concave portion 212 are formed by overlapping the convex portion and the concave portion provided on the substrate mat 220 and the web 270, respectively. The convex portion and the concave portion of the mat material are shaped to fit together when the mat material is wrapped around an exhaust gas purification device, an exhaust gas treatment body, or an exhaust pipe having a cylindrical outer periphery. In FIG. 5, the direction indicated by the double-headed arrow W is the widthwise direction of the mat material, and the direction indicated by the double-headed arrow T is the thickness direction of the mat material.

[0083] 5 shows the case where the web 270 is formed only on the first main surface 221 of the base mat 220, but the web 270 may be formed on each of the first main surface 221 and the second main surface 222 of the base mat 220. Furthermore, in addition to the first main surface 221 and / or the second main surface 222 of the base mat 220, the web 270 may also be formed on the side surfaces of the base mat 220.

[0084] Fig. 6 is an enlarged plan view schematically showing the web shown in Fig. 5. In Fig. 6, the base mat 220 is also shown with a dashed line to show the positional relationship between the web 270 and the base mat 220. As shown in Fig. 6, the web 270 is formed of fiber bundles 271 formed by intertwining a plurality of fibers and single fibers 272. This prevents a decrease in the strength and flexibility of the fibers forming the web 270, thereby preventing cracks from occurring when the mat material 210 is wrapped around the web.

[0085] The multiple fibers that make up the fiber bundle 271 are twisted and entangled with each other. Because the fibers that make up the fiber bundle 271 are not fused to each other but are simply entangled, the flexibility of the web 270 can be prevented from decreasing, as described above. The number of fibers that make up the fiber bundle 271 is not particularly limited, but is preferably 2 to 10, and more preferably 3 to 7. The single fibers 272 are fibers that are not entangled with other fibers.

[0086] The fiber bundle 271 includes a plurality of fiber bundles having different stretching directions, and the web 270 is formed from these plurality of fiber bundles and single fibers 272. As a result, the number of fibers in the longitudinal direction and the number of fibers in the transverse direction in the web 270 can be made approximately the same.

[0087] Here, the fibers forming the web 270 include longitudinally oriented fibers 231 and laterally oriented fibers 232 that extend in two directions, the longitudinal direction and the transverse direction, respectively. The longitudinally oriented fibers 231 are oriented in the longitudinal direction, which is approximately parallel to the longitudinal direction of the mat material 210 (the direction indicated by the double-headed arrow L in FIG. 6 ). The laterally oriented fibers 232 are oriented in the transverse direction, which is approximately parallel to the transverse direction of the mat material 210 (the direction indicated by the double-headed arrow W in FIG. 6 ). Here, the direction in which the length directions of the fibers constituting the longitudinally oriented fibers 231 are aligned is the orientation direction of the longitudinally oriented fibers 231, and the direction in which the length directions of the fibers constituting the transversely oriented fibers 232 are aligned is the orientation direction of the transversely oriented fibers 232. The longitudinally oriented fibers 231, whose fibers are oriented (aligned) in the longitudinal direction, and the transversely oriented fibers 232, whose fibers are oriented (aligned) in the transverse direction, are layered to form a nonwoven fabric with longitudinal and transverse fiber orientations.

[0088] This nonwoven fabric is produced using a manufacturing process in which raw materials are spun directly into yarn, and the spun fibers are stretched in both the longitudinal and transverse directions to orient the long fiber filaments in both the longitudinal and transverse directions. This nonwoven fabric is also an openwork nonwoven fabric, and has openings surrounded by longitudinally oriented fibers 231 and transversely oriented fibers 232.

[0089] Some of the fibers of the longitudinally oriented fibers 231 are entangled to form longitudinally oriented fiber bundles 271a extending in the vertical direction, while the remaining fibers of the longitudinally oriented fibers 231 exist as longitudinally oriented single fibers 272a extending in the vertical direction. Similarly, some of the fibers of the laterally oriented fibers 232 are entangled to form laterally oriented fiber bundles 271b extending in the horizontal direction, while the remaining fibers of the laterally oriented fibers 232 exist as laterally oriented single fibers 272b extending in the horizontal direction.

[0090] However, the fibers forming the web 270 do not necessarily need to be stretched linearly, and it is preferable that at least a portion of the fibers forming the web 270 are curved. That is, as shown in Fig. 6, it is preferable that curved fiber bundles 271c and curved single fibers 272c are present. This increases the number of intersections between the fibers forming the web 270, which can disperse stress applied to the web 270 and further suppress the occurrence of cracks when the mat material 210 is wound. More specifically, the curved fiber bundles 271c and the curved single fibers 272c are each curved, for example, in an arc shape, along their orientation direction (longitudinal or transverse direction).

[0091] Although only one of the curved fiber bundles 271c and the curved single fibers 272c may be present, it is preferable that both are present from the viewpoint of preventing cracking of the mat material 210.

[0092] 6 shows a case where one layer of each of the longitudinally oriented fibers 231 and the horizontally oriented fibers 232 is laminated, the number of layers of the longitudinally oriented fibers 231 and the horizontally oriented fibers 232 is not particularly limited, and three or more layers of the longitudinally oriented fibers 231 and the horizontally oriented fibers 232 may be laminated alternately. Furthermore, the order in which the longitudinally oriented fibers 231 and the horizontally oriented fibers 232 are laminated is also not particularly limited.

[0093] In this way, the web 270 is formed three-dimensionally. That is, the web 270 extends in the longitudinal and lateral directions of the mat material 210 and has a thickness in the thickness direction of the mat material 210. This further improves the strength of the web 270 and distributes the stress applied to the web 270, making it possible to more effectively prevent cracks from occurring when the mat material 210 is wrapped around it.

[0094] In addition, the web 270 may contain fibers that extend in three or more directions, for example, in addition to the vertically oriented fibers 231 and the horizontally oriented fibers 232, it may contain fibers that extend diagonally, and these fibers may contain fiber bundles and single fibers that extend diagonally.

[0095] Furthermore, the relationship between the orientation directions of the longitudinally oriented fibers 231 and the laterally oriented fibers 232 and the longitudinal and transverse directions of the mat material 210 is not particularly limited, but it is preferable that one of the orientation directions of the longitudinally oriented fibers 231 and the laterally oriented fibers 232 is parallel to the longitudinal direction of the mat material 210 and the other of the orientation directions of the longitudinally oriented fibers 231 and the laterally oriented fibers 232 is parallel to the transverse direction of the mat material 210. In other words, it is preferable that the orientation direction of either the longitudinally oriented fiber bundles 271a and the longitudinally oriented monofilaments 272a extending in the vertical direction or the laterally oriented fiber bundles 271b and the laterally oriented monofilaments 272b extending in the horizontal direction is parallel to the longitudinal direction of the mat material 210 and the other orientation direction is parallel to the transverse direction of the mat material 210.

[0096] The web 270 shown in FIGS. 5 and 6 further has a plurality of bases 273 made of an organic material, and fiber bundles 271 and single fibers 272 extend in a plurality of directions from each base 273.

[0097] The bases 273 are distributed within the web 270, and unlike fibers that extend one-dimensionally, each base 273 extends in the longitudinal direction, lateral direction, and thickness direction (particularly the longitudinal direction and lateral direction) of the mat material 210. The bases 273 are fused together to bond the fiber bundles 271 and the monofilaments 272 that extend in different directions to each other. In other words, the bases 273 are arranged in regions where the fiber bundles 271 and the monofilaments 272 intersect, and bond these fibers to each other.

[0098] The base 273 also serves to secure the web 270 to the substrate mat 220. That is, the base 273 bonds the fibers forming the web 270 to the substrate mat 220 by fusing.

[0099] In this way, the web 270 is formed by a nonwoven fabric in which fiber bundles 271 and single fibers 272 oriented in multiple directions (e.g., vertically oriented fibers 231 and horizontally oriented fibers 232) are laminated, and bases 273 that are distributed on the nonwoven fabric and bond fibers of different orientation directions (e.g., vertically oriented fibers 231 and horizontally oriented fibers 232) located in different layers. Details of these components will be described below.

[0100] The substrate mat constituting the mat material according to the second aspect of the present invention is made of inorganic fibers. The inorganic fibers are not particularly limited and may be alumina-silica fibers, alumina fibers, silica fibers, etc. Glass fibers or biosoluble fibers may also be used. The inorganic fibers may be changed depending on the properties required of the mat material, such as heat resistance and wind erosion resistance, and it is preferable to use fibers with a large diameter and fiber length that comply with the environmental regulations of each country.

[0101] Among these, inorganic fibers of low crystalline alumina are preferred, inorganic fibers of low crystalline alumina having a mullite composition are more preferred, and inorganic fibers containing a spinel compound are even more preferred.

[0102] The substrate mat has a longitudinal direction, which is the wrapping direction, and a lateral direction perpendicular to the longitudinal direction. It is preferable that the substrate mat has a convex portion formed at one of the longitudinal ends, i.e., a first end, and a concave portion formed at the other end, i.e., a second end. It is preferable that the convex portion and the concave portion of the substrate mat are shaped so that they fit together perfectly when the mat material is wrapped around an exhaust gas purification device, an exhaust gas treatment body, or an exhaust pipe, which has a cylindrical outer periphery. Alternatively, the substrate mat may have a shape in which no convex portion or concave portion is formed.

[0103] The thickness of the base mat is preferably 2 to 30 mm. If the thickness of the base mat is less than 2 mm, the thickness is too thin, resulting in reduced thermal insulation and soundproofing performance. On the other hand, if the thickness of the base mat exceeds 30 mm, the flexibility decreases, resulting in reduced attachment to the component to which it is attached.

[0104] The bulk density of the base mat is not particularly limited, but is preferably 0.05 to 0.30 g / cm ３It is preferable that the bulk density of the base mat is 0.05 g / cm ３ If the bulk density of the base mat is less than 0.30 g / cm, the entanglement of the inorganic fibers is weak and the inorganic fibers are easily peeled off, making it difficult to maintain the desired shape of the base mat. ３ If the hardness exceeds 100%, the base mat becomes hard, the attachability to the member to be attached decreases, and the base mat becomes more likely to crack.

[0105] A web is formed on at least one of the first and second main surfaces of the base mat constituting the mat material according to the second aspect of the present invention, comprising fiber bundles formed by intertwining a plurality of fibers and single fibers.

[0106] The fibers forming the web (hereinafter referred to as web fibers) are preferably long fiber filaments. The long fiber filaments are preferably longer than ordinary staple fibers (e.g., 10 to 50 mm), and the average fiber length of the filaments is preferably longer than 100 mm, and more preferably the average fiber length of the filaments is several hundred mm or more. The long fiber filaments may be continuous long fibers.

[0107] The average fiber diameter of the web fibers, in terms of the main constituent filaments, is usually 10 μm or less, and preferably around 5 μm.

[0108] The web may further include a plurality of substrates constructed from an organic material.

[0109] The organic material constituting the base is different from the material of the web fibers, and specifically, the base is formed by thermally fusing a hot melt powder (hot melt adhesive) to the web fibers.

[0110] Therefore, it is preferable that the glass transition temperature Tg3 of the web fibers is higher than the glass transition temperature Tg4 of the organic material constituting the base. This makes it possible to easily form a web having a base using a hot melt powder.

[0111] The glass transition point Tg3 of the web fibers is not particularly limited, but is preferably −140° C. or higher and 90° C. or lower, and more preferably −130° C. or higher and 80° C. or lower. The glass transition point Tg4 of the organic material constituting the base is also not particularly limited, but is preferably −140° C. or higher and 90° C. or lower, and more preferably −130° C. or higher and 80° C. or lower. Furthermore, the difference between the glass transition point Tg3 of the web fibers and the glass transition point Tg4 of the organic material constituting the base, i.e., (Tg3−Tg4), is not particularly limited, but is preferably 220° C. or lower, and more preferably 200° C. or lower in order to integrate the web fibers and the base.

[0112] The organic material constituting the base is not particularly limited as long as it can be used as a hot melt powder, and specific examples include polyethylene (PE), polyethylene terephthalate (PET), polyamide (PA), ethylene-vinyl acetate copolymer resin (EVA), etc.

[0113] The web preferably has substantially the same planar shape as the base mat. That is, it is preferable that the areas where the web and the base mat are arranged substantially coincide in a plan view. It is also preferable that a sheet material is formed from the web, and this sheet material is attached to the base mat. The sheet material and the base mat are preferably attached via hot melt powder.

[0114] The basis weight of the sheet material made of the web is not particularly limited, but is preferably 5 g / m ２ Above, 100g / m ２ Preferably, it is 5 g / m or less. ２ Above, 50g / m ２ More preferably, it is 5 g / m or less. ２ Above, 30g / m ２ It is more preferable that the basis weight of the sheet material mentioned here is the basis weight per sheet of the sheet material.

[0115] The web fibers are preferably composed of at least one of organic fibers and inorganic fibers. For example, the longitudinally oriented fibers may be composed of organic fibers and / or inorganic fibers, and the transversely oriented fibers may be composed of organic fibers and / or inorganic fibers. The longitudinally oriented fibers and the transversely oriented fibers may be made of different materials, but typically, when the longitudinally oriented fibers are composed of organic fibers, the transversely oriented fibers are also made of organic fibers, and when the longitudinally oriented fibers are composed of inorganic fibers, the transversely oriented fibers are also made of inorganic fibers.

[0116] The web fibers are preferably organic fibers, which can more effectively prevent cracks from occurring when the mat material is wound around the web. For example, both the longitudinally oriented fibers and the transversely oriented fibers may be organic fibers.

[0117] More specifically, suitable materials for the web fibers include polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), and the like.

[0118] In the mat material according to the second aspect of the present invention, the base mat preferably further includes at least one of an inorganic binder and an organic binder. The amount of the inorganic binder used (weight of the inorganic binder / weight of the mat material) may be, for example, more than 0 wt % and not more than 15 wt %. The amount of the organic binder used (weight of the organic binder / weight of the mat material) may be, for example, more than 0 wt % and not more than 15 wt %.

[0119] As the inorganic binder, alumina sol, silica sol, etc. can be used.

[0120] As the organic binder, it is preferable to use water-soluble organic polymers such as acrylic resin, acrylate latex, rubber latex, carboxymethyl cellulose or polyvinyl alcohol, thermoplastic resins such as styrene resin, thermosetting resins such as epoxy resin, etc.

[0121] Next, a method for manufacturing a mat material according to a second aspect of the present invention will be described. The method for manufacturing a mat material according to the second aspect of the present invention can include the following steps: a substrate mat preparation step of preparing a substrate mat containing inorganic fibers and having first and second main surfaces; a sheet material preparation step of preparing a sheet material containing fiber bundles formed by entanglement of a plurality of fibers and single fibers; a sheet material processing step of spraying hot melt powder on the sheet material, heating the sheet material, and adhering the hot melt powder to the sheet material; and a sheet material attachment step of thermocompression-bonding the sheet material with the hot melt powder attached to at least one of the first and second main surfaces of the substrate mat to attach the sheet material to the substrate mat.

[0122] In this case, it is preferable to produce two types of matting materials, a first matting material and a second matting material, both of which are matting materials according to the second aspect of the present invention.

[0123] In the above manufacturing method, first, a substrate mat having first and second main surfaces and a sheet material including fiber bundles formed by entanglement of a plurality of fibers and single fibers are prepared. The structure and physical properties of the substrate mat prepared here are the same as those of the substrate mat described in the mat material according to the second aspect of the present invention, and therefore a detailed description thereof will be omitted. Furthermore, the structure and physical properties of the sheet material prepared here are the same as those of the web described in the mat material according to the second aspect of the present invention, except that it does not have a base portion, and therefore a detailed description thereof will be omitted. However, the substrate mat and sheet material prepared here are preferably large sheets that can be punched to obtain a large number of mat materials according to the second aspect of the present invention.

[0124] The substrate mat can be obtained by various methods, for example, a papermaking method or a needling method. More specifically, it can be produced by the method described in the method for producing the mat material of the present invention, which is a method for producing the mat material according to the first aspect of the present invention.

[0125] The sheet material can be manufactured by, for example, the method described in the method for manufacturing the mat material of the present invention, which is a method for manufacturing the mat material according to the first aspect of the present invention.

[0126] 7 is a perspective view showing a schematic diagram of another example of an adhesive body. The adhesive body 350 is a rectangular sheet having two vertical sides and two horizontal sides, with a large sheet material 330 attached to a first main surface 321 of a large base mat 320. The sheet material 330 is a laminate of vertically oriented fibers and horizontally oriented fibers (both including fiber bundles and single fibers), with the orientation direction of the vertically oriented fibers of the sheet material 330 being vertical and parallel to the two vertical sides of the adhesive body 350, and the orientation direction of the horizontally oriented fibers of the sheet material 330 being horizontal and parallel to the two horizontal sides of the adhesive body 350.

[0127] Subsequently, the adhesive body is subjected to a punching process, whereby a mat member having a predetermined shape can be produced.

[0128] In the above-described manufacturing method, a hot melt powder is sprayed and heated on a sheet material including fiber bundles formed by intertwining multiple fibers and single fibers, the hot melt powder is adhered to the sheet material, and the sheet material with the hot melt powder adhered thereto is thermocompressed to at least one of the first and second main surfaces of a base mat to adhere the sheet material to the base mat. This allows the sheet material to be adhered to the base mat while preventing the fibers forming the sheet material, i.e., the web fibers themselves, from melting. This more effectively prevents a decrease in the strength and flexibility of the web fibers. As a result, the occurrence of cracks during wrapping of the mat material can be more effectively prevented.

[0129] In the punching process of the adhesive body, it is preferable to carry out a process of obtaining a first mat material in which the vertical direction of the adhesive body is the longitudinal direction of the mat material and the horizontal direction of the adhesive body is the short side direction of the mat material, and a second mat material in which the horizontal direction of the adhesive body is the longitudinal direction of the mat material and the vertical direction of the adhesive body is the short side direction of the mat material, thereby obtaining two types of mat material, the first mat material and the second mat material.

[0130] FIG. 8 is a top view schematically illustrating another example of a process for obtaining two types of mat materials by punching. Punching is performed on the adhesive body 350 shown in FIG. 8 to obtain two types of mat materials. The left side of FIG. 8 shows the production of a first mat material 201 in which the orientation direction of the longitudinally oriented fibers (including fiber bundles and single fibers) of the sheet material (the longitudinal direction shown in FIG. 8 ) is the longitudinal direction of the mat material, and the orientation direction of the transversely oriented fibers (including fiber bundles and single fibers) of the sheet material (the transverse direction shown in FIG. 8 ) is the short-side direction of the mat material. The right side of FIG. 8 shows the production of a second mat material 202 in which the orientation direction of the transversely oriented fibers (including fiber bundles and single fibers) of the sheet material (the transverse direction shown in FIG. 8 ) is the longitudinal direction of the mat material, and the orientation direction of the longitudinally oriented fibers (including fiber bundles and single fibers) of the sheet material (the longitudinal direction shown in FIG. 8 ) is the short-side direction of the mat material.

[0131] In the first mat material 201 and the second mat material 202, the number and density of the fibers of the sheet material oriented in the longitudinal direction of the mat material (longitudinal or horizontally oriented fibers) and the number and density of the fibers of the sheet material oriented in the short direction of the mat material (horizontal or vertically oriented fibers) are the same, so they exhibit approximately the same tensile strength and windability.

[0132] In addition, in the punching process, it is preferable that the orientation direction of one of the longitudinally oriented fibers and the transversely oriented fibers of the sheet material is parallel to the longitudinal direction of the first mat material and parallel to the short direction of the second mat material. It is also preferable that the orientation direction of the other of the longitudinally oriented fibers and the transversely oriented fibers of the sheet material is parallel to the short direction of the first mat material and parallel to the longitudinal direction of the second mat material. The punching direction shown in Figure 8 is a direction that satisfies the above conditions.

[0133] In the above manufacturing method, a fiber bundle formed by intertwining multiple fibers, a sheet material containing single fibers (a laminated sheet material in which vertically oriented fibers and horizontally oriented fibers are laminated), and hot melt powder are used. However, the mat material according to the second aspect of the present invention can also be manufactured without using these.

[0134] Specifically, for example, longitudinally oriented fibers (longitudinal stretched web) containing fiber bundles and single fibers and impregnated with a binder may be heat-pressed onto at least one of the first and second main surfaces of the base mat, and then horizontally oriented fibers (horizontally stretched web) containing fiber bundles and single fibers and impregnated with a binder may be heat-pressed onto the longitudinally oriented fibers.

[0135] The exhaust gas purification device of the present invention is described below. The exhaust gas purification device of the present invention is an exhaust gas purification device including an exhaust gas treatment body through which exhaust gas flows, a holding seal material that is used by being wrapped around the outer periphery of the exhaust gas treatment body, and a casing that houses the exhaust gas treatment body around which the holding seal material is wrapped, wherein the holding seal material is the mat material according to the first or second aspect of the present invention.

[0136] As described above, the mat material according to the first and second aspects of the present invention can suppress the occurrence of cracks during winding, and therefore the exhaust gas purification device of the present invention can suppress the leakage of untreated exhaust gas through cracks in the mat material (holding sealing material).

[0137] Fig. 9 is a cross-sectional view schematically showing one example of an exhaust gas purification apparatus of the present invention. As shown in Fig. 9, the exhaust gas purification apparatus 100 of the present invention includes a casing 50, an exhaust gas treatment body 40 housed in the casing 50 and through which exhaust gas flows, and a holding seal material 60 disposed between the exhaust gas treatment body 40 and the casing 50 and holding the exhaust gas treatment body 40. The holding seal material 60 is a mat material wrapped around the outer periphery of the exhaust gas treatment body.

[0138] The exhaust gas treatment body 40 is a columnar structure in which a large number of cells 41 are arranged in parallel in the longitudinal direction, separated by cell walls 42. One end of each cell is sealed with a sealing material 43. Note that, as necessary, an inlet pipe for introducing exhaust gas discharged from the internal combustion engine and an outlet pipe for discharging exhaust gas that has passed through the exhaust gas purification device to the outside are connected to the ends of the casing 50.

[0139] The case where exhaust gas passes through the exhaust gas purification device 100 having the above-described configuration will be described below with reference to FIG. 9 . As shown in FIG. 9 , exhaust gas emitted from an internal combustion engine and flowing into the exhaust gas purification device 100 (in FIG. 9 , the exhaust gas is indicated by G, and the flow of the exhaust gas is indicated by arrows) flows into one cell 41 opening at the exhaust gas inlet end face of the exhaust gas treatment body (honeycomb filter) 40 and passes through a cell wall 42 separating the cells 41. At this time, PM in the exhaust gas is captured by the cell wall 42, and the exhaust gas is purified. The purified exhaust gas flows out of another cell 41 opening at the exhaust gas outlet end face and is discharged to the outside.

[0140] In the exhaust gas purification device 100 shown in Figure 9, the holding sealing material 60 is a mat material according to the first or second aspect of the present invention, and at least one of the first and second main surfaces of the holding sealing material 60 is composed of a network constituting the mat material according to the first aspect of the present invention, or a web constituting the mat material according to the second aspect of the present invention.

[0141] The material of the casing constituting the exhaust gas purifying device of the present invention is not particularly limited as long as it is a heat-resistant metal, and specific examples thereof include metals such as stainless steel, aluminum, and iron.

[0142] The casing may be of a generally cylindrical shape, a clamshell shape, or a generally elliptical or polygonal shape in cross section.

[0143] 9 is a filter in which one end of the cells 41 is sealed with a sealing material 43, but the exhaust gas treatment body constituting the exhaust gas purifying device of the present invention does not need to have the cell ends sealed. Such an exhaust gas treatment body can be suitably used as a catalyst carrier.

[0144] The exhaust gas treatment body 40 may be made of a non-oxide porous ceramic such as silicon carbide or silicon nitride, or may be made of an oxide porous ceramic such as alumina, cordierite, or mullite. Of these, silicon carbide is preferred.

[0145] The cell density in the cross section of the exhaust gas treatment body 40 is not particularly limited, but the preferred lower limit is 31.0 cells / cm ２ (200 pieces / inch ２ ), the preferred upper limit is 93.0 particles / cm ２ (600 pieces / inch ２ A more preferable lower limit is 38.8 particles / cm ２ (250 pieces / inch ２ ), and a more preferable upper limit is 77.5 particles / cm ２ (500 pieces / inch ２ )

[0146] The exhaust gas treatment body 40 may be supported with a catalyst for purifying the exhaust gas. The supported catalyst is preferably a precious metal such as platinum, palladium, or rhodium, with platinum being more preferred. Other catalysts may also be used, such as alkali metals such as potassium or sodium, or alkaline earth metals such as barium. These catalysts may be used alone or in combination of two or more. Supporting these catalysts facilitates the combustion and removal of PM, making it possible to purify toxic exhaust gases.

[0147] The use of the mat material of the present invention is not particularly limited, and in addition to applications in exhaust gas purification devices, it may also be used, for example, in batteries. More specifically, it can also be used in power storage devices used in electric vehicles or hybrid vehicles driven by electric motors. For example, by placing the mat material on the surface of power storage device components such as battery cells of the power storage device or bus bars connecting battery cells, it is possible to suppress damage to other power storage device components even if thermal runaway occurs, in which a battery cell suddenly rises in temperature and continues to generate heat due to an internal short circuit or overcharging of the battery cells. Furthermore, by using the mat material of the present invention on the lid, side walls, and bottom walls of a battery case that houses a storage battery, it is possible to reliably prevent the spread of fire to the outside even if a flame breaks out during thermal runaway. In this case, it is more preferable to use the mat material of the present invention in a stacked configuration.

[0148] The present specification discloses the following:

[0149] The present disclosure (1) is a mat material characterized in that a substrate mat contains inorganic fibers and has first and second main surfaces, and a network is formed on at least one of the first and second main surfaces by a plurality of bases made of an organic substance and fibers extending in at least two directions from each of the plurality of bases.

[0150] The present disclosure (2) is a mat material according to the present disclosure (1), wherein the maximum width of each of the plurality of base portions is greater than the width of the fibers forming the network.

[0151] The present disclosure (3) is a mat material according to the present disclosure (1) or (2), in which the glass transition temperature of the fibers forming the network is higher than the glass transition temperature of the organic material constituting the plurality of base portions.

[0152] The present disclosure (4) is a mat material in any combination with any of the present disclosures (1) to (3), in which the network is formed three-dimensionally.

[0153] The present disclosure (5) is a mat material in any combination with any of the present disclosures (1) to (4), in which the fibers forming the network are composed of at least one of organic fibers and inorganic fibers.

[0154] The present disclosure (6) is a mat material characterized in that a substrate mat contains inorganic fibers and has first and second main surfaces, and a web is formed on at least one of the first and second main surfaces by fiber bundles formed by intertwining a plurality of fibers and single fibers.

[0155] The present disclosure (7) is the mat material according to the present disclosure (6), which includes a plurality of the fiber bundles having different stretching directions, and the web is formed by the plurality of the fiber bundles and the single fibers.

[0156] The present disclosure (8) is the mat material according to the present disclosure (6) or (7), in which at least one of the fiber bundles and the single fibers is curved.

[0157] The present disclosure (9) is a mat material in any combination with any of the present disclosures (6) to (8), wherein the web is formed three-dimensionally.

[0158] The present disclosure (10) is a mat material in any combination with any of the present disclosures (6) to (9), wherein the fiber bundles and the single fibers are each composed of at least one of organic fibers and inorganic fibers.

[0159] The present disclosure (11) is an exhaust gas purification device comprising: an exhaust gas treatment body through which exhaust gas flows; a holding seal material that is used by being wrapped around the outer periphery of the exhaust gas treatment body; and a casing that houses the exhaust gas treatment body around which the holding seal material is wrapped, wherein the holding seal material is a mat material that is any combination of any of the present disclosures (1) to (10).

[0160] The present disclosure (12) is a method for manufacturing a mat material, comprising: a substrate mat preparation step of preparing a substrate mat containing inorganic fibers and having first and second main surfaces; a sheet material preparation step of preparing a sheet material containing fibers extending in at least two directions; a sheet material processing step of spraying hot melt powder on the sheet material, heating it, and adhering the hot melt powder to the sheet material; and a sheet material attachment step of thermocompressing the sheet material with the hot melt powder attached to at least one of the first and second main surfaces of the substrate mat, and attaching the sheet material to the substrate mat.

[0161] EXAMPLES The following examples more specifically disclose the present invention, but the present invention is not limited to these examples.

[0162] (Example 1) A papermaking method was used to produce a paper sheet with a basis weight (fiber weight per unit area) of 2400 g / m ２ A large substrate mat was fabricated from inorganic fibers (mullite fibers) with a fiber orientation in both the longitudinal and transverse directions, in which longitudinally oriented fibers in which PET fibers are oriented in the longitudinal direction and transversely oriented fibers in which PET fibers are oriented in the transverse direction were laminated as the large sheet material (nonwoven fabric). This sheet material has orientation in the direction in which the length of the PET fibers are aligned, and the angle between the orientation direction of the longitudinally oriented fibers and the orientation direction of the transversely oriented fibers is approximately 90°. This sheet material also has substantially square or rectangular openings. Furthermore, this sheet material has a basis weight of 10 g / m ２ is.

[0163] The hot melt powder was sprinkled on the sheet material and heated to adhere to the sheet material. The hot melt powder used was polyethylene (PE)-based.

[0164] The base mat and the sheet material with the hot melt powder attached were thermally pressed together to attach the sheet material to the base mat. The heating temperature was 130°C for 40 seconds, and constant pressure was applied. As a result, a network was formed on the surface of the base mat, consisting of multiple bases made of organic matter and longitudinally oriented fibers and transversely oriented fibers extending from each of the multiple bases in two directions, the longitudinal direction and the transverse direction, respectively.

[0165] As a result, a rectangular patch body similar to the patch body shown schematically in Figure 3 was obtained. The patch body was then punched in the same manner as the arrangement shown schematically in Figure 4 to obtain two types of mat materials (a first mat material and a second mat material). In the first mat material, the orientation direction of the longitudinally oriented fibers of the sheet material is parallel to the longitudinal direction of the mat material, and in the second mat material, the orientation direction of the transversely oriented fibers of the sheet material is parallel to the longitudinal direction of the mat material.

[0166] (Example 2) A papermaking method was used to produce a paper sheet with a basis weight (fiber weight per unit area) of 2400 g / m ２ A large-sized substrate mat was fabricated from inorganic fibers (mullite fibers). A laminated sheet material (nonwoven fabric) with longitudinal and transverse fiber orientations, consisting of longitudinally oriented fibers in which PET fibers are oriented in the longitudinal direction and transversely oriented fibers in which PET fibers are oriented in the transverse direction, was prepared as the large-sized sheet material. The PET fibers were oriented in the direction of their length, and the angle between the longitudinally oriented fibers and the transversely oriented fibers was approximately 90°. The longitudinally oriented fibers included fiber bundles formed by intertwining multiple fibers and single fibers, while the transversely oriented fibers included fiber bundles formed by intertwining multiple fibers and single fibers. The sheet material had substantially square or rectangular openings. Furthermore, the sheet material had a basis weight of 10 g / m. ２ is.

[0167] The hot melt powder was sprinkled on the sheet material and heated to adhere to the sheet material. The hot melt powder used was polyethylene (PE)-based.

[0168] The base mat and the sheet material with the hot melt powder attached were heat-pressed together to attach the sheet material to the base mat. The heating temperature was 135°C for 35 seconds, and the heating time was constant. As a result, a web was formed on the surface of the base mat, consisting of fiber bundles extending in both the longitudinal and transverse directions and monofilaments extending in both the longitudinal and transverse directions.

[0169] As a result, a rectangular patch body similar to the patch body shown schematically in Figure 7 was obtained. The patch body was then punched in the same manner as the arrangement shown schematically in Figure 8 to obtain two types of mat materials (a first mat material and a second mat material). In the first mat material, the orientation direction of the longitudinally oriented fibers of the sheet material is parallel to the longitudinal direction of the mat material, and in the second mat material, the orientation direction of the transversely oriented fibers of the sheet material is parallel to the longitudinal direction of the mat material.

[0170] Comparative Example 1 A large-sized base mat was produced in the same manner as in Examples 1 and 2. A large-sized sheet material was prepared by laminating and heat-sealing a longitudinal web formed by splitting a longitudinally stretched polyolefin film and a transverse web formed by splitting a transversely stretched polyolefin film and having a transversely oriented fiber. The base mat and the sheet material were heat-pressed together without using an adhesive such as a hot melt powder. That is, the sheet material was heat-sealed to the base mat. As a result, a rectangular adhesive body having two longitudinal sides and two transverse sides was obtained. The adhesive body was then punched in the same manner as in Examples 1 and 2 to obtain two types of mat materials (a first mat material and a second mat material). In the first mat material, the orientation direction (longitudinal direction) of the longitudinal web of the sheet material was parallel to the longitudinal direction of the mat material, and in the second mat material, the orientation direction (transverse direction) of the transverse web of the sheet material was parallel to the longitudinal direction of the mat material.

[0171] (Presence or absence of cracks in mat material) Two types of mat material (first mat material and second mat material) manufactured in each example and comparative example were each wrapped around a cylindrical substrate having a diameter of 200 mm. When wrapping, the base mat was placed on the substrate side, and the sheet material was placed on the outside. Then, the presence or absence of cracks was confirmed for each mat material after wrapping. The results are shown in Table 1. In the presence or absence of cracks, ○ indicates no cracks, and × indicates the presence of cracks.

[0172]

[0173] These results demonstrate that cracking during wrapping can be prevented by forming a network on the surface of the substrate mat using multiple bases made of organic matter and fibers extending in at least two directions from each of the multiple bases. Furthermore, by forming a web on the surface of the substrate mat using fiber bundles formed by entanglement of multiple fibers and single fibers, cracking during wrapping can be prevented. Figure 10 is a photograph of the mat material of Comparative Example 1. As shown in Figure 10, cracks occurred in the area surrounded by the dashed line after wrapping in the mat material of Comparative Example 1. Furthermore, in the mat material of Comparative Example 1, tiny holes were formed in the fibers of the sheet material after thermocompression bonding, and multiple fibers were fused to each other. This is thought to have weakened the flexibility of the sheet material, causing cracking after wrapping.

[0174] DESCRIPTION OF SYMBOLS 1, 201 First mat material 2, 202 Second mat material 10, 210 Mat material 11, 211 Convex portion 12, 212 Concave portion 20, 120, 220, 320 Base material mat 21, 121, 221, 321 First main surface of base material mat 22, 222 Second main surface of base material mat 130, 330 Sheet material 31, 231 Longitudinal orientation fiber 32, 232 Lateral orientation fiber 40 Exhaust gas treatment body 41 Cell 42 Cell wall 43 Sealing material 50 Casing 60 Holding sealing material 70 Network 71, 273 Base 72 Fiber 100 Exhaust gas purification device 150, 350 Adhesive body 270 Web 271 Fiber bundle 271a Longitudinal orientation fiber bundle 271b Laterally oriented fiber bundle 271c Curved fiber bundle 272 Single fiber 272a Vertically oriented single fiber 272b Laterally oriented single fiber 272c Curved single fiber

Claims

1. A mat material comprising a base mat containing inorganic fibers and having first and second main surfaces, characterized in that a network is formed on at least one of the first and second main surfaces by a plurality of bases made of an organic substance and fibers extending in at least two directions from each of the plurality of bases.

2. The mat material according to claim 1 , wherein the maximum width of each of the plurality of base portions is greater than the width of the fibers forming the network.

3. 3. The mat material according to claim 1, wherein the glass transition point of the fibers forming the network is higher than the glass transition point of the organic material constituting the plurality of base portions.

4. 3. The mat material according to claim 1, wherein the network is formed three-dimensionally.

5. 3. The mat material according to claim 1, wherein the fibers forming the network are composed of at least one of organic fibers and inorganic fibers.

6. A mat material comprising a base mat containing inorganic fibers and having first and second main surfaces, wherein a web is formed on at least one of the first and second main surfaces from fiber bundles formed by intertwining a plurality of fibers and single fibers.

7. The fiber bundles include a plurality of fiber bundles having different stretch directions, The mat material according to claim 6 , wherein the web is formed of a plurality of the fiber bundles and the single fibers.

8. 8. The mat material according to claim 6, wherein at least one of the fiber bundles and the single fibers is curved.

9. 8. The mat member according to claim 6, wherein the web is formed three-dimensionally.

10. 8. The mat material according to claim 6, wherein the fiber bundles and the monofilaments are each composed of at least one of organic fibers and inorganic fibers.

11. an exhaust gas treatment body through which exhaust gas flows; A holding seal material that is wrapped around the outer periphery of the exhaust gas treatment body; a casing that accommodates the exhaust gas treatment body around which the holding sealing material is wrapped; An exhaust gas purification device comprising:

8. An exhaust gas purification device, wherein the holding and sealing material is the mat material according to claim 1, 2, 6 or 7.

12. providing a substrate mat including inorganic fibers and having first and second major surfaces; A sheet material preparation step of preparing a sheet material including fibers extending in at least two directions; a sheet material processing step of spraying hot melt powder on the sheet material and heating the sheet material to adhere the hot melt powder to the sheet material; a sheet material attachment step of thermocompressing the sheet material having the hot melt powder adhered thereto to at least one of the first and second main surfaces of the base mat, thereby attaching the sheet material to the base mat.