Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
  • D04H1/541—Composite fibres, e.g. sheath-core, sea-island or side-by-side; Mixed fibres
  • D04H1/5412—Composite fibres, e.g. sheath-core, sea-island or side-by-side; Mixed fibres sheath-core
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4326—Condensation or reaction polymers
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
  • D04H1/4326—Condensation or reaction polymers
  • D04H1/4334—Polyamides
  • D04H1/4342—Aromatic polyamides
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
  • D04H1/541—Composite fibres, e.g. sheath-core, sea-island or side-by-side; Mixed fibres
  • D04H1/5418—Mixed fibres, e.g. at least two chemically different fibres or fibre blends
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
  • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
  • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
  • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
  • D04H1/558—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving in combination with mechanical or physical treatments other than embossing
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2505/00—Industrial

Definitions

• the present invention relates to a heat-resistant fiber structure that is composed of heat-resistant fibers and is used as a heat insulating material or a sound absorbing material, and a method for manufacturing the same.
• fiber materials such as fiber structures used for these applications, low density is required from the viewpoint of light weight, and strength such as bending stress and tensile strength is also required. Powerfulness at is important. For example, strength at high temperatures is strongly demanded in sound absorbing heat insulating materials incorporated in aircraft wall surfaces and filter applications incorporated in automobile engine parts.
• a heat insulating sound absorbing material in which a cotton-like material mixed with a binder is matted has been proposed. More specifically, for example, a high heat-resistant inorganic fiber and a flame-retardant organic fiber having a heat melting temperature or a thermal decomposition temperature of 350 ° C. or higher are uniformly mixed, and the resulting cotton-like material is heat-resistant.
• a heat-insulating sound-absorbing material is disclosed in which the resin binder is applied and a cotton-like material is heat-treated to form a mat. And it is described by using such a heat insulation sound-absorbing material that a heat insulation sound-absorbing material with high safety can be provided by high heat insulation and sound absorption.
• the present invention has been made in view of the above-described problems, and an object thereof is to provide a heat-resistant fiber structure having heat resistance and excellent strength such as bending stress and tensile strength.
• the heat-resistant fiber structure of the present invention is a fiber structure containing heat-resistant fibers having a glass transition temperature of 100 ° C. or higher, and the heat-resistant fibers are bonded to each other.
• the heat-resistant fiber structure of the present invention (hereinafter simply referred to as “fiber structure”) is composed of a plurality of heat-resistant fibers bonded to each other. And unlike the said conventional fiber structure, the fiber structure of this invention does not use a low-melting-point binder fiber, but has excellent heat resistance and strength by directly bonding heat-resistant fibers to each other. It has the characteristic of providing.
• adheresion refers to a state in which fibers are softened by heating and the fibers are deformed and meshed by the overlapping force at the intersection, or the fibers are fused and integrated.
• Heat resistant fiber As the heat-resistant fiber constituting the fiber structure, a fiber having a glass transition temperature Tg of 100 ° C. or higher is used.
• the glass transition temperature (the temperature at which a polymer starts microscopic molecular motion) is used as an index of heat resistance.
• a resin having a glass transition point of 100 ° C. or higher is called an engineering plastic. It is preferably used for applications requiring heat resistance.
• the fiber using this resin as a raw material is called heat resistant fiber.
• This heat-resistant fiber is a fiber that is softened by high-temperature superheated steam (150 ° C. to 600 ° C.) and can be self-adhesive.
• polyamide fiber, meta-aramid fiber, para-aramid fiber, melamine fiber, polybenzoxazole fiber, Polybenzimidazole fiber, polybenzothiazole fiber, polyarylate fiber, polyethersulfone fiber, liquid crystal polyester fiber, polyimide fiber, polyetherimide fiber, polyetheretherketone fiber, polyetherketone fiber, polyetherketoneketone fiber, polyamideimide A fiber etc. can be mentioned. None of these fibers may be used alone or as a mixture of two or more.
• polyamide fibers are preferably used from the viewpoint of low water absorption and chemical resistance
• polyetherimide fibers are used from the viewpoint of flame retardancy and low smoke generation. preferable.
• polyamide fiber for example, a fiber made of a semi-aromatic polyamide which is a polyamide obtained from an aliphatic diamine and a dicarboxylic acid mainly containing an aromatic component is used.
• the dicarboxylic acid mainly composed of an aromatic component means that at least 60 mol% or more is an aromatic dicarboxylic acid.
• Preferred examples include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and the like.
• the polyetherimide fiber an amorphous polyetherimide fiber having no melting point is used, and the glass transition temperature Tg may be 200 ° C. or higher, even if the fineness is 200 ° C. Those that retain heat resistance under high temperature conditions are preferred.
• Such heat resistance can be judged from the dry heat shrinkage at 200 ° C., and the amorphous polyetherimide fiber used as the heat resistant fiber of the present invention is dry heat shrinkage at 200 ° C. May be 5.0% or less, and specifically, the dry heat shrinkage is preferably -1.0 to 5.0%.
• the amorphous polyetherimide fiber is derived from a polymer and is excellent in flame retardancy.
• the limiting oxygen index value may be 25 or more, preferably 28 or more, More preferably, it may be 30 or more.
• the amorphous polyetherimide fiber may have a single fiber fineness of 15.0 dtex or less.
• the single fiber fineness is preferably 0.1 to 12.0 dtex, and more preferably 0.5 to 10.0 dtex.
• the amorphous polyetherimide fiber has a fiber strength at room temperature of 2.0 cN / dtex or more.
• the fiber strength is less than 2.0 cN / dtex, the process passability when making a fabric such as paper, non-woven fabric, or woven fabric may be deteriorated. More preferably, it is 2.3 to 4.0 cN / dtex, and further preferably 2.5 to 4.0 cN / dtex.
• the cross-sectional shape of the heat-resistant fiber is a general cross-sectional shape such as a round cross-section or an irregular cross-section (flat, elliptical, polygonal, 3-14 leaf shape). , T-shape, H-shape, V-shape, dogbone (I-shape, etc.), and may be a hollow cross-section.
• the average fineness of the heat-resistant fiber can be selected, for example, from the range of 0.01 to 100 dtex, preferably 0.1 to 50 dtex, more preferably 0.5 to 30 dtex (particularly 1 to 10 dtex) depending on the application. . When the average fineness is within this range, the balance between the strength of the fiber and the expression of adhesiveness is excellent.
• the average fiber length of the heat resistant fiber can be selected, for example, from a range of 10 to 100 mm, preferably 20 to 80 mm, more preferably 25 to 75 mm (especially 35 to 55 mm). When the average fiber length is within this range, the fibers are sufficiently entangled, so that the mechanical strength of the fiber structure is improved.
• the crimp rate of the heat resistant fiber is, for example, 1 to 50%, preferably 3 to 40%, more preferably 5 to 30% (particularly 10 to 20%).
• the number of crimps is, for example, 1 to 100 pieces / inch, preferably 5 to 50 pieces / inch, and more preferably 10 to 30 pieces / inch.
• the fiber structure of the present invention includes the above-described heat-resistant fiber and has a structure in which the heat-resistant fibers are bonded to each other, and the shape can be selected according to the use, but is usually a sheet or plate shape. It is.
• a non-woven fiber web is formed. It is necessary that the arrangement state and adhesion state of the fibers to be adjusted are appropriately adjusted. That is, it is desirable that the fibers constituting the fiber web are arranged so as to intersect each other while being arranged substantially parallel to the surface of the fiber web (non-woven fiber).
• the fiber structure of the present invention is bonded at the intersection where the fibers intersect.
• a fiber structure (molded body) that requires high hardness and strength is a bundle-like adhesive that is bonded in a bundle of several to several tens when fibers other than the intersections are arranged substantially in parallel. Fibers may be formed.
• a structure in which "scram” is assembled by partially forming a structure in which these fibers are bonded at the intersection of single fibers, the intersection of bundle fibers, or the intersection of single fibers and bundle fibers (Structure in which the fibers are bonded at the intersection and entangled like a mesh, or the structure in which the fibers are bonded at the intersection and constrain the adjacent fibers to each other), and the desired bending behavior, surface hardness, etc. can be expressed. .
• arranged substantially parallel to the surface of the fiber web means that a portion where a large number of fibers are locally arranged along the thickness direction is not repeatedly present. Indicates. More specifically, when an arbitrary cross section of the fiber web of the fiber structure is observed with a microscope, the existence ratio (number of fibers) continuously extending in the thickness direction over 30% of the thickness of the fiber web. The ratio) is 10% or less (particularly 5% or less) with respect to all the fibers in the cross section.
• Fibers are arranged in parallel to the fiber web surface because if there are many fibers oriented along the thickness direction (perpendicular to the web surface), the fiber arrangement may be disturbed in the periphery. This is because an unnecessarily large void is generated in the woven fiber, and the bending strength and surface hardness of the fiber structure are reduced. Therefore, it is preferable to reduce this gap as much as possible. For this purpose, it is desirable to arrange the fibers as parallel to the fiber web surface as possible.
• the fibrous structure of the present invention is a sheet-like or plate-like molded body
• a load is applied in the thickness direction of the fibrous structure
• the void is crushed by the load.
• the surface of the molded body is easily deformed.
• this load is applied to the entire surface of the molded body, the thickness tends to be reduced as a whole. Therefore, this problem can be avoided if the fiber structure itself is made of a resin filling without voids, but this reduces the air permeability, ensuring that it is difficult to bend when bent (folding resistance) and lightweight. It becomes difficult to do.
• the fiber structure of the present invention is arranged such that the directions of the fibers are arranged in parallel along the surface direction of the web and dispersed (or the fiber directions are directed in a random direction), so that the fibers intersect each other, and the intersections thereof.
• a small gap is generated to ensure light weight.
• an appropriate air permeability and surface hardness are secured.
• a bundle of fibers bonded in parallel in the fiber length direction is formed in a place where the fibers are aligned in parallel without intersecting with other fibers, it is higher than the case where the fibers are composed of only single fibers. Bending strength can be mainly secured.
• the fiber adhesion rate due to adhesion of heat-resistant fibers is preferably 10 to 85%, more preferably 25 to 75%, and more preferably 40 to 65%. Further preferred.
• this fiber adhesion rate can be measured by the method described in the examples described later, and indicates the ratio of the number of cross sections of two or more fibers bonded to the total number of cross sections of the non-woven fiber cross section. Therefore, a low fiber adhesion rate means that the proportion of the plurality of fibers adhering to each other (the proportion of the fibers that are converged and adhered) is small.
• the heat-resistant fibers constituting the non-woven fiber structure are bonded at the contact points of the respective fibers, but in order to develop a large bending stress with as few contacts as possible, this bonding point has a thickness of It is preferable to distribute uniformly along the direction from the surface of the fiber structure to the inside (center portion) and the back surface.
• the adhesion points are concentrated on the surface or inside, it is not only difficult to secure a sufficient bending stress, but also the form stability in a portion where the adhesion points are small.
• the central portion of the three regions divided in three in the thickness direction is in the above range (10 to 85%).
• the uniformity of the fiber adhesion rate in each region is preferably 20% or less (for example, 0.1 to 20%), preferably 15% or less (for example, 0.5 to 15%), more preferably 10% or less (for example, 1 to 10%).
• the fiber structure of the present invention is excellent in hardness, bending strength, folding resistance and toughness because the fiber adhesion rate has such uniformity in the thickness direction.
• region divided into three in the thickness direction means each region divided into three equal parts by slicing in a direction perpendicular to the thickness direction of the plate-like fiber structure. To do.
• the fiber structure of the present invention not only the adhesion by the heat-resistant fiber is uniformly dispersed and the point adhesion is performed, but also the point adhesion of these point adhesion is short (for example, several tens to several hundreds ⁇ m). ) In the network structure. With such a structure, the fiber structure of the present invention has a high followability to strain due to the flexibility of the fiber structure even when an external force is applied, and at each adhesion point of finely dispersed fibers. Since the external force is dispersed and reduced, it can be estimated that high bending stress and tensile strength are expressed.
• the conventional fiber structure in which heat resistant fibers are bonded to each other through binder fibers has a small number of bonding points because the amount of binder fibers is limited to ensure heat resistance, and the binder fibers. Even if the amount of adhesive is increased and the adhesion point is increased, heat resistance cannot be obtained, and furthermore, it is difficult to uniformly disperse the adhesive in the thickness direction of the fiber structure. Can be estimated.
• the existence frequency of single fibers (single fiber end faces) in the cross section in the thickness direction is not particularly limited.
• the existence frequency of single fibers existing at an arbitrary 1 mm 2 of the cross section may be 100 fibers / mm 2 or more (for example, 100 to 300 fibers), but in particular, mechanical characteristics are required rather than light weight.
• the frequency of single fibers is, for example, 100 / mm 2 or less, preferably 60 / mm 2 or less (for example, 1 to 60 / mm 2 ), and more preferably 25 / mm 2. It may be the following (for example, 3 to 25 pieces / mm 2 ).
• the fibers bonded in a bundle shape are thin in the thickness direction of the molded body and have a wide shape in the surface direction (length direction or width direction).
• the presence frequency of single fibers is measured as follows. That is, the range corresponding to 1 mm 2 selected from the scanning electron microscope (SEM) photograph of the cross section of the compact is observed, and the number of single fiber cross sections is counted. Arbitrary several places (for example, 10 places selected at random) are observed in the same manner, and the average value per unit area of the single fiber end face is defined as the existence frequency of single fibers. At this time, all the number of fibers in a single fiber state are counted in the cross section. That is, in addition to fibers that are completely in a single fiber state, even if fibers are bonded to each other, fibers that are in a single fiber state apart from the bonded portion in the cross section are counted as single fibers.
• the heat-resistant fiber in the fiber structure can suppress the loss of the fiber structure due to the loss of the fiber by not connecting the both ends in the thickness direction (the fiber does not penetrate the fiber structure in the thickness direction).
• a manufacturing method for arranging the heat-resistant fibers in this way is not particularly limited, but a means for laminating a plurality of fiber molded bodies entangled with the heat-resistant fibers and bonding them with superheated steam is simple and reliable.
• the fiber which connects the both ends of the thickness direction of a fiber structure can be reduced significantly by adjusting the relationship between fiber length and the thickness of a fiber structure.
• the thickness of the fiber structure is 10% or more (for example, 10 to 1000%), preferably 40% or more (for example, 40 to 800%), more preferably 60% with respect to the fiber length. Or more (for example, 60 to 700%), more preferably 100% or more (for example, 100 to 600%).
• the thickness and fiber length of the fiber structure are within such ranges, the mechanical structure such as bending stress of the fiber structure is not lowered, and the loss of the fiber structure due to the fiber dropping or the like can be suppressed.
• the density and mechanical properties of the fiber structure of the present invention are affected by the ratio and the presence state of the bundle-like adhesive fibers.
• the fiber adhesion rate indicating the degree of adhesion can be easily measured based on the number of bonded fiber cross sections in a predetermined region by taking a photograph of an enlarged cross section of the fiber structure using SEM.
• the fibers are bonded in a bundle shape, the fibers are bonded in a bundle shape or at an intersection, and therefore, when the density is particularly high, it is difficult to observe as a single fiber.
• the fiber filling rate in the cross section in the thickness direction is, for example, 20 to 80%, preferably 20 to 60%, and more preferably 30 to 50%. If the fiber filling rate is too small, there are too many voids in the fiber structure, making it difficult to ensure the desired surface hardness and bending stress. On the other hand, if it is too large, the surface hardness and bending stress can be sufficiently secured, but it becomes very heavy and the air permeability tends to decrease.
• the fiber structure of the present invention (particularly, the fiber structure in which fibers are bonded in a bundle and the frequency of single fibers is 100 / mm 2 or less) is plate-like (board-like), depending on the load. It is preferable to have a surface hardness that hardly causes deformation such as formation of a concave shape.
• the hardness by an A-type durometer hardness test (a test in accordance with the “hardness test method for vulcanized rubber and thermoplastic rubber” of JIS K6253) is, for example, A50 or more, preferably A60 or more. More preferably, it is A70 or more. If this hardness is too small, it is likely to be deformed by a load applied to the surface.
• a fiber structure including such bundle-like adhesive fibers has a low frequency of bundle-like adhesive fibers, and each fiber (bundle) in order to balance bending strength, surface hardness, lightness, and air permeability at a high level. It is preferable that the fibers are bonded at a high frequency at the intersection of the filamentous fibers and / or single fibers). However, if the fiber adhesion rate is too high, the distances between the bonded points are too close to each other, the flexibility is lowered, and it becomes difficult to eliminate distortion due to external stress. For this reason, as described above, the fiber structure of the present invention preferably has a fiber adhesion rate of 85% or less.
• the fiber adhesion rate When the fiber adhesion rate is not too high, a passage by a fine gap can be secured in the fiber structure, and the lightness and air permeability can be improved. Therefore, in order to develop a large bending stress, surface hardness and air permeability with as few contacts as possible, the fiber adhesion rate increases in the thickness direction from the surface of the fiber structure to the inside (center) and back. It is preferable to distribute uniformly along.
• the fiber adhesion rate in the central portion is in the above-described range. It is preferable that all of the front surface, the central portion, and the back surface are in the above-described range. Further, the difference between the maximum value and the minimum value of the fiber adhesion rate in each region may be 20% or less (for example, 0.1 to 20%), preferably 15% or less (for example, 0.5 to 15).
• the fiber adhesion rate is uniform in the thickness direction, the bending stress, tensile strength, folding resistance, toughness and the like are excellent.
• the fiber adhesion rate in this invention is measured by the method as described in the Example mentioned later.
• One feature of the fiber structure of the present invention is that it exhibits a bending behavior that cannot be obtained with a conventional fiber structure in which heat-resistant fibers are bonded via binder fibers.
• the bending stress is measured from the repulsive force and bending amount of the sample when the sample is gradually bent according to JIS K7171 “Plastics-Determination of bending characteristics”. Used as an indicator of behavior. That is, the larger the bending stress, the harder the fiber structure, and the more the bending amount (displacement) until the measurement object breaks, the better the bent body.
• the bending stress in at least one direction is 0.05 MPa or more (for example, 0.05 to 100 MPa), preferably 0.1 to 30 MPa, more preferably 0. It may be 2 to 10 MPa. If this bending stress is too small, it is easily broken by its own weight or a slight load when used as a board material. Further, if the bending stress is too high, it becomes too hard, and if it is bent beyond the peak of the stress, it is easily broken and broken. In addition, in order to obtain the hardness exceeding 100 MPa, it is necessary to increase the density of the fiber structure, and it is difficult to ensure light weight.
• the fiber structure of the present invention can ensure excellent lightness due to voids generated between fibers. Further, unlike the resin foam such as sponge, these voids are continuous rather than independent voids, and thus have air permeability. Such a structure is a structure that is extremely difficult to produce by conventional hardening methods such as a method of impregnating a resin and a method of forming a film-like structure by closely adhering surface portions. .
• the fiber structure of the present invention has a low density.
• the apparent density is, for example, 0.03 to 0.7 g / cm 3 , and particularly in applications that require lightweight, 0.05 to 0.5 g / cm 3 , preferably 0.08 to 0.4 g / cm 3 , and more preferably 0.1 to 0.35 g / cm 3 .
• the apparent density is, for example, 0.2 to 0.7 g / cm 3 , preferably 0.25 to 0.65 g / cm 3 , more preferably 0.3 to It may be 0.6 g / cm 3 . If the apparent density is too low, it is lightweight, but it is difficult to ensure sufficient bending hardness and surface hardness.
• the fibers are entangled and close to a general nonwoven fiber structure bonded at the intersection point, while when the density is increased, the fibers are bonded in a bundle shape and are close to a porous molded body. It becomes.
• Appent density means the density calculated based on the fabric weight and thickness measured based on the prescription
• Basis weight of the fibrous structure of the present invention can be selected from 50 ⁇ 10000g / m 2 approximately in the range of preferably 150 ⁇ 8000g / m 2, more preferably 300 ⁇ 6000g / m 2 approximately.
• a basis weight for example, 1000 ⁇ 10000g / m 2, preferably 1500 ⁇ 8000g / m 2, further preferably about 2000 ⁇ 6000g / m 2. If the basis weight is too small, it is difficult to ensure the hardness, and if the basis weight is too large, the web is too thick and the superheated steam cannot sufficiently enter the web during processing with superheated steam. It becomes difficult to obtain a uniform fiber structure.
• the thickness is not particularly limited, but can be selected from the range of about 1 to 100 mm, for example, 2 to 50 mm, preferably 3 to 20 mm, more preferably Is 5 to 150 mm. If the thickness is too thin, it will be difficult to ensure the hardness, and if it is too thick, the mass will also become heavy, so the handling properties as a sheet will be reduced.
• the air permeability of the fiber structure of the present invention is 0.1 cm 3 / cm 2 / sec or more (for example, 0.1 to 300 cm 3 / cm 2 / sec), preferably 0.5 to 3 in terms of air permeability according to the Frazier method. 250 cm 3 / cm 2 / sec (for example, 1 to 250 cm 3 / cm 2 / sec), more preferably 5 to 200 cm 3 / cm 2 / sec, and usually 1 to 100 cm 3 / cm 2 / sec. If the air permeability is too small, it is necessary to apply pressure from the outside in order to allow air to pass through the fiber structure, making it difficult for natural air to enter and exit. On the other hand, if the air permeability is too high, the air permeability increases, but the fiber voids in the fiber structure become too large, and the bending stress decreases.
• the fiber structure of the present invention has a non-woven fiber structure, it has high heat insulation and low thermal conductivity of 0.1 W / m ⁇ K or less, for example, 0.03 to 0.1 W / m. ⁇ K, preferably 0.05 to 0.08 W / m ⁇ K.
• the heat-resistant fiber described above is formed into a web.
• a conventional method for example, a direct method such as a spunbond method or a meltblowing method, a card method using meltblown fibers or staple fibers, a dry method such as an airlay method, or the like can be used.
• a card method using melt blown fibers or staple fibers particularly a card method using staple fibers is widely used.
• the web obtained using staple fibers include a random web, a semi-random web, a parallel web, and a cross-wrap web. Of these webs, a semi-random web and a parallel web are preferred when the proportion of bundled adhesive fibers is increased.
• the means for bonding the fibers may be a conventional hot air treatment or hot pressing, or the fibers may be bonded by superheated steam.
• the fiber web obtained in the above process is sent to the next process by a belt conveyor and exposed to a superheated steam (high pressure steam) flow, whereby the fiber structure having the nonwoven fiber structure of the present invention. Is obtained. That is, the fiber web conveyed by the belt conveyor passes through the superheated steam flow ejected from the nozzle of the steam spraying device, and the heat-resistant fibers are three-dimensionally bonded to each other by the sprayed superheated steam (thermal bonding). Is done.
• the heat-resistant fibers can be bonded to each other to obtain a fiber network, so that the inside of the fiber structure in the thickness direction is uniform and It becomes possible to process bulky.
• the temperature of the superheated steam sprayed onto the heat resistant fiber is preferably in the range of 150 to 600 ° C. This is because if the temperature is lower than 150 ° C, the energy given to the heat-resistant fibers is insufficient, and the adhesion between the fibers may be insufficient. This is because the uniformity of the fiber adhesion rate may be lowered.
• the belt conveyor to be used is not particularly limited as long as it can be processed with superheated steam while compressing the fiber web used for processing to a desired density, and an endless conveyor is preferably used.
• it may be a general single belt conveyor, or may be transported by combining two belt conveyors as necessary and sandwiching the web between both belts.
• a steam injection device for supplying superheated steam to the web is installed in one conveyor and supplies superheated steam to the web through a conveyor net.
• a suction box may be attached to the opposite conveyor. The suction box can suck and discharge excess superheated steam that has passed through the web.
• a suction box is installed in the downstream part of the conveyor on the side where the superheated steam injection device is installed, and this suction box is installed.
• a superheated steam spraying device may be installed in the opposite conveyor.
• the endless belt used for the conveyor is not particularly limited as long as it does not interfere with web transport and overheated steam treatment.
• the surface shape of the belt may be transferred to the surface of the fiber web depending on the conditions.
• a fine mesh net is used in the case of a fiber structure having a flat surface.
• the upper limit is 90 mesh, and a fine net having a mesh larger than this has low air permeability and makes it difficult for steam to pass through.
• the mesh belt is made of metal, heat-treated polyester resin, polyphenylene sulfide resin, polyarylate resin (fully aromatic polyester resin), aromatic polyamide from the viewpoint of heat resistance against superheated steam treatment.
• a heat resistant resin such as a resin is preferable.
• the superheated steam injected from the steam injection device is an air stream, unlike the hydroentanglement process or the needle punching process, the superheated steam enters the web without greatly moving the fibers in the web as the object to be processed. It is considered that due to the entry and superheating action of the steam flow into the web, the superheated steam flow effectively covers the surface of each heat-resistant fiber present in the web in a superheated state, thereby enabling uniform thermal bonding. In addition, since this process is performed in a very short time under a high-speed air stream, the heat conduction of the superheated steam to the fiber surface is sufficient, but the process is completed before the heat conduction to the inside of the fiber is sufficiently performed.
• the web to be processed is placed between a conveyor belt or rollers with a desired apparent density ( For example, it is important to expose to superheated steam in a compressed state of 0.03 to 0.7 g / cm 3 ).
• a relatively high-density fiber structure is to be obtained, it is necessary to compress the fiber web with sufficient pressure when processing with superheated steam.
• the back side of the endless belt on the opposite side of the nozzle across the web is made of a stainless steel plate or the like so that the steam cannot pass through. Since it reflects here, it adhere
• a suction box may be arranged to discharge excess steam to the outside.
• the nozzle for injecting superheated steam may be a plate or die in which predetermined orifices are continuously arranged in the width direction, and the orifices may be arranged in the width direction of the web to be supplied. There may be one or more orifice rows, and a plurality of rows may be arranged in parallel. A plurality of nozzle dies having a single orifice array may be installed in parallel.
• the thickness of the plate may be 0.5 to 1 mm.
• the orifice diameter and pitch are not particularly limited as long as the target fiber fixation is possible, but the orifice diameter is usually 0.05 to 2 mm, preferably 0.1 to 1 mm, more preferably. 0.2 to 0.5 mm.
• the pitch of the orifices is usually 0.5 to 3 mm, preferably 1 to 2.5 mm, more preferably 1 to 1.5 mm. If the orifice diameter is too small, the processing accuracy of the nozzle becomes low and the processing becomes difficult, and the operational problem that clogging is likely to occur easily occurs. On the other hand, if it is too large, the steam injection force is reduced.
• the superheated steam is not particularly limited as long as the heat-resistant fiber can be fixed, and may be set depending on the material and form of the fiber used.
• the pressure is, for example, 0.1 to 2 MPa, preferably 0.2 to 1. 0.5 MPa, more preferably 0.3 to 1 MPa. If the pressure of the steam is too high or too strong, the fibers forming the web may move and cause turbulence, or the fibers may melt too much to partially retain the fiber shape. Also, if the pressure is too weak, it may not be possible to give the web the amount of heat necessary for fiber bonding, or superheated steam may not penetrate the web, and fiber adhesion spots may occur in the thickness direction. It may be difficult to control the uniform jet of steam.
• the fiber structure having a non-woven fiber structure obtained in this way has a very high bending stress and surface hardness while having a low density comparable to that of a general nonwoven fabric, and also has air permeability, sound absorption, In addition to heat insulation, it has heat resistance. Therefore, using such performance, it can be applied to applications requiring heat resistance such as automobile interior materials, aircraft inner walls, building material boards, and the like.
• Example 1 ⁇ Production of fiber structure>
• Semi-aromatic polyamide resin consisting of diamine having 9 carbon atoms and terephthalic acid (trade name: GENESTAR, melting point: 265 ° C., glass transition temperature: 125 ° C., thermal decomposition temperature: 400 ° C. ) was used (fineness: 1.7 dtex, fiber length: 51 mm).
• a card web having a basis weight of 50 g / m 2 was prepared by a card method, and twelve sheets of this web were stacked to obtain a card web having a total basis weight of 600 g / m 2 .
• the card web was transferred to a belt conveyor equipped with a 50 mesh, 500 mm wide stainless steel endless net.
• this belt conveyor consists of a pair of conveyor of a lower conveyor and an upper conveyor, and the vapor
• a metal roll for adjusting the web thickness (hereinafter sometimes abbreviated as “web thickness adjusting roll”) is provided on each conveyor upstream of the nozzle.
• the lower conveyor has a flat upper surface (that is, the surface through which the web passes), and one upper conveyor has a lower surface bent along a web thickness adjusting roll.
• the adjusting roll is arranged to make a pair with the web thickness adjusting roll of the lower conveyor.
• the upper conveyor can be moved up and down, so that the web thickness adjusting rolls of the upper conveyor and the lower conveyor can be adjusted to a predetermined interval.
• the upstream side of the upper conveyor is inclined at an angle of 30 degrees (relative to the lower surface on the downstream side of the upper conveyor) with respect to the downstream portion with respect to the web thickness adjusting roll, and the downstream portion is parallel to the lower conveyor. It is bent so that it may be arranged.
• Each of these belt conveyors rotates in the same direction at the same speed, and the two conveyor belts and the web thickness adjusting rolls can be pressurized while maintaining a predetermined clearance.
• This is for adjusting the web thickness before steaming by operating like a so-called calendar process. That is, the card web fed from the upstream side travels on the lower conveyor, but the interval with the upper conveyor is gradually narrowed before reaching the web thickness adjusting roll. And when this space
• the roll for adjusting the web thickness was adjusted to have a linear pressure of 50 kg / cm.
• the steam web is introduced into the steam jetting device provided in the lower conveyor, and steam treatment is performed by ejecting superheated steam at 300 ° C. in the thickness direction of the card web (perpendicularly) from this device.
• the fiber structure which has the nonwoven fiber structure in a present Example was obtained.
• a nozzle is installed in the lower conveyor so as to blow superheated steam toward the web via a conveyor net, and a suction device is installed on the upper conveyor.
• another jetting device which is a combination in which the arrangement of the nozzle and the suction device is reversed, is installed on the downstream side in the web traveling direction of the jetting device, and superheated steam treatment is performed on both the front and back sides of the web. gave.
• the hole diameter of the steam injection nozzle was 0.3 mm, and the steam injection device in which the nozzles were arranged in a line at a 1 mm pitch along the width direction of the conveyor was used.
• the processing speed was 3 m / min, and the interval (distance) between the upper and lower conveyor belts on the nozzle side and the suction side was 5 mm.
• the nozzles were arranged on the back side of the conveyor belt so as to be almost in contact with the belt.
• the ratio of the number of cross-sections in a state where two or more fibers are bonded out of the total number of cross-sections of fibers that can be recognized in each region is expressed as a percentage based on the following formula (1).
• the part which fibers contact there is a part which is simply contacting without bonding, and a part which is bonded by bonding, but by cutting the fiber structure for microscopic photography, the fiber In the cut surface of the structure, the fibers that are simply in contact with each other were separated by the stress of each fiber. Therefore, in the cross-sectional photograph, the contacting fibers are assumed to be bonded.
• ⁇ Measurement of tensile strength> In accordance with the provisions of JIS L1913 (general non-woven fabric test method), a test piece (width 30 mm, length 150 mm) is prepared from the produced fiber structure, the grip interval is 100 mm, and the test speed is 10 mm / min. Tensile strength (N / 30 mm) was measured. The results are shown in Table 1.
• Example 2 ⁇ Production of fiber structure>
• amorphous polyetherimide fiber manufactured by Kuraray Co., Ltd., trade name: KURAKIISSS, glass transition temperature: 215 ° C., thermal decomposition temperature: 540 ° C., fineness: 8.9 dtex, fiber length 51 mm
• a card web having a basis weight of 100 g / m 2 was prepared by a card method, and formed into a sheet using a hydroentanglement method.
• the laminated body was transferred to a belt conveyor equipped with a 50 mesh, 500 mm wide stainless steel endless net.
• the curd web is introduced into the steam injection device provided in the lower conveyor, and superheated steam at 330 ° C. is passed from the device toward the thickness direction of the card web. (Perpendicularly) and steam treatment was performed to obtain a fiber structure having a nonwoven fiber structure in this example.
• Example 3 ⁇ Production of fiber structure>
• Nine card webs used in Example 1 were laminated and subjected to a hot press treatment at 260 ° C. for 1 minute using a hot press apparatus to obtain a fiber structure.
• a card web having a basis weight of 50 g / m 2 was prepared by using the mixed cotton fiber by a card method, and six sheets of this web were stacked to obtain a card web having a total basis weight of 300 g / m 2 .
• the fiber structure of this comparative example was obtained by heat-processing this card
• the fiber structures of Examples 1 to 3 in which heat-resistant fibers having a glass transition temperature of 100 ° C. or higher are thermally bonded to each other are compared in which the heat-resistant fibers are bonded to each other through a binder. It is superior to the fiber structure of Example 1 in bending stress and tensile strength. In particular, in the fiber structures of Examples 1 and 2 with high uniformity of fiber adhesion, the values of bending stress and tensile strength are significantly higher than those of Comparative Example 1, and the strength is very excellent. I can say that.
• the bending stress of the fiber structure of Comparative Example 1 is 0, but such a fiber structure is soft enough to bend by its own weight, and the bending stress is below the measurement limit, For example, even when it is constructed as a heat insulating material, it is inferior in handleability because it hangs down without being along a wall surface or a ceiling surface.
• the bending stress of Example 3 is 0.4 MPa, which is superior to that of Comparative Example 1. If the bending stress is about 0.4 MPa, construction can be performed without sagging from the wall surface. It can be said that it is greatly improved from the viewpoint of.
• Example 3 Compared with Comparative Example 1, it can be said that the maintenance ratio of tensile strength (tensile strength at 180 ° C./tensile strength at normal temperature) is large and excellent in heat resistance. .
• Comparative Example 1 since the fibers are bonded to each other with a binder, the fiber adhesion rate is remarkably reduced as shown in Table 1. As a result, the bending stress and It can be said that the tensile strength is extremely low.
• the present invention is composed of heat resistant fibers and is suitable for heat resistant fiber structures used as heat insulating materials and sound absorbing materials.

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• 2017
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