JP2019203210A - Fiber structure - Google Patents

Abstract

To provide a fiber structure capable of easily obtaining a complicated shape while having excellent sound absorbing characteristics.SOLUTION: There is provided a fiber structure comprising an ultrafine staple fiber having a fineness of less than 1 dtex and a heat adhesive staple fiber having a fineness of 1 dtex or more. The ultrafine staple fiber is a fiber having a silicon content of 10 to 5,000 ppm and a crimp number of 10/25.4 mm(1 inch) or more. The heat adhesive staple fiber has a melting point lower than the melting point of the ultrafine staple fiber by 40°C or more. A blending amount of the ultrafine staple fiber is 10 to 90 wt.% and a blending amount of the heat adhesive staple fiber is 5 to 50 wt.% based on the total of the fiber structure and the fiber structure has an average density of 0.1 g/cmor less. Further, it is preferable that the resin constituting the ultrafine staple fiber is made of a polyester resin or a polyolefin resin, and that the polyester resin is a polyalkylene terephthalate resin or a polyalkylene naphthalate resin, and that the polyolefin resin is a polyethylene resin or a polyolefin resin. In addition, it is preferable that the silicon in the ultrafine staple fiber is derived from at least one kind of dimethylpolysiloxane, amino-modified polysiloxane, hydroxy-modified polysiloxane, and polyoxyethylene copolymerized polydimethylsiloxane, and that the melting point of the ultrafine staple fiber is 200°C or higher.SELECTED DRAWING: None

Description

  The present invention relates to a fiber structure, and further comprises an interior dry nonwoven fabric for automobiles, a dry nonwoven fabric for houses, a highway dry nonwoven fabric, a nonwoven fabric for electrical products, a nonwoven fabric for compressors, a cotton pad for clothing, a cotton pad for bedding, and the like. It relates to a fiber structure.

  Conventionally, nonwoven fabrics excellent in sound absorption and insulation are widely used as structures used in vehicles, houses, highways, electrical products, compressors, and the like.

  For example, felt made by impregnating a wood board or recycled fiber with a thermosetting binder such as phenol resin, nonwoven fabric (for example, Patent Document 1) obtained by impregnating a thermoplastic resin with inorganic fiber such as glass fiber, and the like. A fiber assembly (for example, Patent Document 2) composed of a high-melting thermoplastic fiber and a low-melting thermoplastic fiber, wherein a part of the low-melting thermoplastic fiber is thermally fused, an inelastic crimped short fiber, and a heat-adhesive composite A sound absorbing fiber structure (for example, Patent Document 3) composed of short fibers, in which fixing points are formed by heat fusion of the heat-bondable composite short fibers, and the fibers are arranged in the thickness direction, and a sheet on the fiber structure A laminated body (for example, Patent Document 4) in which the objects are bonded is proposed.

  On the other hand, it is also known to use fine fibers for improving sound absorption and heat insulation properties. For example, a nonwoven fabric made of melt-blown fibers to be fine fibers has been proposed (for example, Patent Document 5). . However, since the fibers are very thin, the thickness is easily deformed with respect to the external pressure, and the ultrafine fibers are easily melted at the time of thermoforming, it is difficult to obtain a nonwoven fabric having a high performance three-dimensional structure. In addition, although a fiber assembly using fine fiber obtained by a method other than melt blowing has been proposed (Patent Document 6), when fine fiber is used, uniform dispersion of fibers and generation of neps It was difficult to prevent and it was difficult to obtain a high-quality fiber structure.

JP 59-227442 A JP-A-7-3599 JP 2001-207366 A JP 2004-209975 A JP-A-6-212546 JP 7-219556 A

  This invention is made | formed in view of said background, The objective is to provide the fiber structure which is easy to obtain a complicated shape, while sound absorption property is favorable.

The fiber structure of the present invention is a fiber structure including ultrafine short fibers having a fineness of less than 1 dtex and thermally adhesive short fibers having a fineness of 1 dtex or more, wherein the ultrafine short fibers have a silicon content of 10 to 5000 ppm and crimped It is a fiber of several tens of 25.4 mm (1 inch) or more, the heat-adhesive short fiber has a melting point that is 40 ° C. or more lower than the melting point of the ultrafine short fiber, and the blending amount of the ultrafine short fiber is 10 to 90% by weight, The blending amount of the heat-adhesive short fibers is 5 to 50% by weight, and the average density of the fiber structure is 0.1 g / cm ³ or less.
Further, the resin constituting the ultrafine short fiber is made of a polyester resin or a polyolefin resin, the polyester resin is a polyalkylene terephthalate resin or a polyalkylene naphthalate resin, and the polyolefin resin is a polyethylene resin or a polyolefin resin. Is preferred.
Further, the number of crimps of the ultrafine short fiber is in the range of 12 / 25.4 mm to 36 / 25.4 mm, and the silicon in the ultrafine short fiber is dimethylpolysiloxane, amino-modified polysiloxane, hydroxy-modified polysiloxane, poly It is preferably derived from at least one of oxyethylene copolymer polydimethylsiloxane, and the melting point of the ultrafine short fiber is 200 ° C. or higher.

  ADVANTAGE OF THE INVENTION According to this invention, although the sound absorption characteristic is favorable, the fiber structure which is easy to obtain a complicated shape is provided.

The fiber structure of the present invention is a fiber structure including ultrafine short fibers having a fineness of less than 1 dtex and thermally adhesive short fibers having a fineness of 1 dtex or more. The ultrafine fiber is a fiber having a silicon content of 10 to 5000 ppm and a crimp number of 10 / 25.4 mm (1 inch) or more, and the heat-adhesive short fiber has a melting point that is 40 ° C. or more lower than the melting point of the ultrafine fiber. Have. Furthermore, it is a fiber structure in which the blending amount of ultrafine short fibers is 10 to 90% by weight, the blending amount of heat-adhesive short fibers is 5 to 50% by weight, and the average density of the fiber structure is 0.1 g / cm ³ or less. .

  Normally, when the fiber diameter of the short fiber is thin and the number of crimps is increased, the entanglement becomes large and the non-uniformity becomes remarkable. However, in the present invention, the constituent fibers have a fineness of less than 1 dtex and the number of crimps is 10/25. Although it contains ultra-fine short fibers of 4 mm (1 inch) or more, by satisfying other requirements, it is excellent in workability even though the fiber diameter is thin and the number of crimps is large, and the ultra-short fibers are uniformly dispersed. And the uniformity of the finally obtained fiber structure is excellent.

  Such ultrafine short fibers and heat-adhesive short fibers used in the fiber structure of the present invention are generally preferably made of a synthetic resin.

  Moreover, as resin which comprises the ultrafine fiber used for the fiber structure of this invention, it is preferable to consist of resin which contains the polyester resin and polyolefin resin excellent in versatility among synthetic fibers.

  In the present invention, such a polyester resin or polyolefin resin can be used alone, but a fiber containing a polyester resin or polyolefin resin only in a part thereof is also preferable. Alternatively, it is also preferable that the ultrafine short fiber used in the present invention is a composite fiber composed of several kinds of resins, and that one component is mainly composed of a polyester resin or a polyolefin resin.

  And if the polyester type resin preferably used in the present invention is specifically exemplified, as the polyester, polyalkylene terephthalate such as polyethylene terephthalate, polytrimethylene terephthalate, or polybutylene terephthalate (polytetramethylene terephthalate), Alternatively, polyesters of aromatic dicarboxylic acids and aliphatic diols such as polyalkylene naphthalates such as polyethylene naphthalate, polytrimethylene naphthalate, or polybutylene naphthalate (polytetramethylene naphthalate) can be exemplified. Alternatively, a polyester obtained from an alicyclic dicarboxylic acid such as polyalkylenecyclohexanedicarboxylate and an aliphatic diol, or a polyester obtained from an aromatic dicarboxylic acid such as polycyclohexanedimethylene terephthalate and an alicyclic diol, polyethylene Examples include polyesters obtained from aliphatic dicarboxylic acids such as succinate, polybutylene succinate or polyethylene adipate and aliphatic diols, or polyesters obtained from polyhydroxycarboxylic acids such as polylactic acid and polyhydroxybenzoic acid. it can. Or as resin used as a polyester-type fiber, the copolymer and blend body by the arbitrary ratios of these polyester components are illustrated preferably.

  Depending on the purpose, the dicarboxylic acid component constituting the polyester may include isophthalic acid, phthalic acid, alkali metal salt of 5-sulfoisophthalic acid, quaternary ammonium salt of 5-sulfoisophthalic acid, and quaternary 5-sulfoisophthalic acid. Phosphonium salt, succinic acid, adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, α, β- (4-carboxyphenoxy) ethane, 4,4-dicarboxyphenyl, 2,6-naphthalenedicarboxylic acid, 2,7 -Naphthalenedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, or a diester compound composed of these organic groups having 1 to 10 carbon atoms may be copolymerized as one component or two or more components. . Similarly, as the diol component constituting the polyester, diethylene glycol, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedi One component or two components of methanol, 2,2-bis (p-β-hydroxyethylphenyl) propane, polyethylene glycol, poly (1,2-propylene) glycol, poly (trimethylene) glycol or poly (tetramethylene) glycol You may copolymerize above. Furthermore, one or two or more components of hydroxycarboxylic acid such as ω-hydroxyalkylcarboxylic acid, pentaerythritol, trimethylolpropane, trimellitic acid, or trimesic acid, or a compound having three or more carboxylic acid components or hydroxyl groups It is also preferable that the polyester is branched by copolymerization. It is also possible to use a mixture of polyesters having different compositions as exemplified above.

  Among them, the polyester-based resin that is preferably used in the present invention is preferably a polyalkylene terephthalate resin or a polyalkylene naphthalate resin from the viewpoint of its physical properties and good handleability.

  The intrinsic viscosity of the fiber constituting the short fiber of the present invention is preferably 0.35 to 0.50, and particularly when the main component constituting the fiber is polyethylene terephthalate, the intrinsic viscosity is 0.35 to 0.00. 50 is particularly preferred. When the intrinsic viscosity is too low, the strength of the fiber is lowered and it tends to be difficult to form a fiber. On the other hand, even if the intrinsic viscosity is too high, the performance of the ultrafine short fiber for a dry nonwoven fabric tends to be lowered due to a decrease in stretchability.

  The resin other than the polyester resin preferably used in the present invention is preferably a polyolefin resin. More specifically, the polyolefin used in the present invention is exemplified by isotactic polypropylene, syndiotactic polypropylene, atactic polypropylene, high density polyethylene, medium density polyethylene, linear low density polyethylene, low density polyethylene, ethylene Preference is given to propylene random copolymerized polyolefin, or polyethylene or polypropylene obtained by block copolymerization or graft copolymerization of the third component.

  The above-mentioned various thermoplastic resins include known additives such as pigments, dyes, matting agents, antifouling agents, antibacterial agents, deodorants, fluorescent whitening agents, antioxidants, It is also a preferred embodiment that the polyester composition contains a flame retardant, a stabilizer, an ultraviolet absorber, or a lubricant. For example, it is particularly preferable to include titanium dioxide as a pigment.

  Furthermore, in the present invention, it is preferable that the ultrafine fiber for dry nonwoven fabric is either a polyester resin or a polyolefin resin, and in particular, a polyethylene terephthalate resin, a copolymerized polyethylene terephthalate resin, a polypropylene resin, a high density One or more kinds of resins selected from polyethylene resins are preferable.

  Now, the ultrafine short fiber used in the present invention is made of a fiber composed of the above-described synthetic resin, and is required to be an ultrafine fiber having a fineness of less than 1 dtex. However, when the single yarn fineness is less than 0.01 dtex, the entanglement between the ultrafine fibers becomes remarkable, and when the single yarn fineness is small, there are many difficulties in terms of the yarn production technique. More specifically, yarn breakage and fluff are generated in the yarn making process, making it difficult to stably produce fibers of good quality. Furthermore, the manufacturing cost tends to increase. Conversely, if the single yarn fineness is too large, the properties of the ultrafine fibers tend not to be reflected in the properties of the resulting nonwoven fabric. In particular, in a nonwoven fabric in a low weight area, it tends to be difficult to obtain the strength and the denseness between fibers when a dry nonwoven fabric is used.

  As the fineness of such ultrafine short fibers, the single yarn fineness is preferably in the range of 0.01 to 1 dtex, more preferably 0.015 to 0.9 dtex, and more preferably 0.02 to 0.6 dtex. It is preferable that it is the range of these. The finer the single yarn fineness, the better the ventilation resistance and sound absorption of the fiber structure, but the finer the fiber, the lower the actual rigidity of the single fiber, and the corresponding increase in the sound absorption rate around 1000 Hz. . In addition, in order to express the effect reliably, it is preferable that the ultrafine short fiber is opened uniformly. On the other hand, when the single yarn fineness is less than 0.01 dtex, the entanglement between the ultrafine fibers becomes remarkable, and when the single yarn fineness is small, there is also a difficulty in the spinning technique. More specifically, not only is it difficult to stably produce fibers of good quality due to the occurrence of yarn breakage and fluff in the yarn making process, but it is also not preferable because the manufacturing cost increases. On the other hand, when the single yarn fineness exceeds 1 dtex, it is not possible to ensure the strength and denseness of a nonwoven fabric or the like in a low-weight area where the feature of ultrafine fibers can be obtained.

  The fiber length of the ultrafine fiber is preferably in the range of 3 to 100 mm, more preferably 4 to 50 mm, and further preferably in the range of 5 to 40 mm. If the fiber length is too small, the aspect ratio represented by the fiber length / width of the fiber cross section or the diameter of the ellipse becomes too small, and the viewpoint of bonding between the fibers constituting the nonwoven fabric, the processability of the nonwoven fabric, and the strength of the nonwoven fabric From the viewpoint of On the other hand, when the fiber length is too long, defects tend to occur due to the entanglement of the fibers.

  The ultrafine short fiber used in the present invention needs to be a crimped fiber, and the number of crimps needs to be 10 / 25.4 mm (inch) or more. Furthermore, it is preferable that it is 10-30 / 25.4mm, and it is especially preferable that it is 15-25 / 25.4mm. If the number of crimps is less than 10 per 25.4 mm (inch), the card process cannot be stably passed. On the other hand, when the number of crimps is too large, even if the other requirements of the present invention are satisfied, the entanglement between the fibers becomes strong and tends to cause defects such as nep.

  And as an ultra fine short fiber used by this invention, it is required that silicon content is 10-5000 ppm. Such silicon may be kneaded in the resin constituting the fiber, but is more preferably disposed on the fiber surface. Further, the content is preferably 30 to 4000 ppm, particularly preferably 50 to 3000 ppm. When the silicon content is less than 10 ppm, the fiber openability and defects due to single yarn breakage increase. On the other hand, when the silicon content exceeds 5000 ppm, the physical properties of the fiber tend to be lowered. In particular, the effect of silicon is more exhibited when other inorganic substances are contained in the ultrafine fiber, and is effective when, for example, the pigment contains titanium dioxide.

  Thus, in order to contain silicon, it is preferable to add as a compound containing silicon. More specifically, examples include dimethylpolysiloxane, amino-modified polysiloxane, hydroxy-modified polysiloxane, polyoxyethylene copolymerized dimethylpolysiloxane, and the like, and preferably includes at least one kind. The above-mentioned compound containing silicon is preferably used particularly when it is disposed on the surface of the fiber. In this case, the compound containing silicon can be applied alone, even if it is electrostatic, convergent, antibacterial, repellent, etc. They may be used in combination with other components having the above functions. As other components, an alkyl phosphate metal salt is preferably contained in the oil agent, and in particular, an alkyl phosphate metal salt having 8 to 18 carbon atoms such as lauryl phosphate metal salt is preferably contained.

  Further, the silicon-containing compound is preferably one that undergoes a crosslinking reaction from the viewpoint of the durability of the silicon component to fall off from the fiber. Such a compound containing silicon is attached to the fiber as a solution and then processed into a fiber by drying or the like, and is contained in the ultrafine short fiber of the present invention.

  When added as a compound, if the silicon content is too small, the fiber openability and defects due to single yarn breakage increase. On the other hand, when there is too much silicon content, an excessive component will become scum and will drop | omit and contaminate in a nonwoven fabric processing process, and a process condition will deteriorate.

  Moreover, in the fiber structure of this invention, it is necessary to contain the heat bondable short fiber whose fineness is 1 dtex or more with the ultrafine short fiber whose fineness is less than 1 dtex as mentioned above.

  Such a heat-adhesive short fiber is preferably a synthetic fiber, and particularly preferably a heat-adhesive composite short fiber. In order to ensure the strength and bulkiness of the fiber structure of the present invention, it is essential to bond the fibers, and in order to further secure the bulkiness, an adhesive component having a low melting point and a component having a high melting point. A composite fiber made of In particular, an adhesive component is a sheath component, and a core-sheath composite fiber in which another normal resin component is a core is preferable. In addition, the heat-sealing component of the heat-bondable short fiber needs to have a melting point that is 40 ° C. or lower lower than the polymer component constituting the ultrafine short fiber. If this temperature is less than 40 ° C., the adhesion becomes insufficient, and the fiber structure that is difficult to handle and has no waist is formed, and the object of the present invention cannot be achieved.

  Further, the heat-adhesive short fibers need to have a fineness of 1 dtex or more, but if the fineness is too small, especially when mechanical fibers are entangled by a needle punch or the like, the nonwoven fabric entanglement step In this case, the needle passage resistance becomes very large, needle breakage occurs, fiber breakage occurs, and the like, and the target fiber structure cannot be obtained.

  Here, as a polymer arranged as a heat fusion component of the heat-adhesive short fibers used in the fiber structure of the present invention, for example, polyurethane-based elastomers, polyester-based elastomers, inelastic polyester-based polymers and copolymers thereof, Examples thereof include polyolefin polymers and copolymers thereof, polyvinyl alcohol polymers, and the like.

  Among the above heat-sealing components, a copolymerized polyester-based polymer is particularly preferable. For example, the copolymerized polyester is preferably copolymerized polyethylene terephthalate obtained by copolymerizing isophthalic acid as a dicarboxylic acid component. In addition, various stabilizers, ultraviolet absorbers, thickening branching agents, matting agents, coloring agents, other various improving agents, and the like may be blended in the above-described polymer as necessary.

  Further, when the heat-adhesive short fiber is a composite fiber, the counterpart component of the heat fusion component is preferably an inelastic polyester resin component, and the polyester resin component is the above-described ultrafine short fiber. It is possible to utilize a resin component equivalent to that used in the fiber. In that case, it is preferable that a heat-fusion component occupies a surface area of 1/2 or more. Furthermore, as a weight ratio thereof, it is preferable that the heat fusion component and the other components are in a range of 30/70 to 70/30 by weight ratio. The form when the heat-adhesive short fiber is a composite short fiber is not particularly limited, but the heat fusion component and other components are preferably side-by-side or core-sheath type, particularly preferably core-sheath type. It is to be. In such a core-sheath type thermoadhesive composite short fiber, other components such as non-elastic polyester serve as a core, and a thermoplastic elastomer serves as a sheath. At this time, the core of the heat-bondable short fiber may be concentric or eccentric.

  Furthermore, it is also preferable that this heat-bondable short fiber contains 10 to 5000 ppm of silicon, which further improves the blendability.

  The heat-adhesive short fibers used in the fiber structure of the present invention preferably have a single fiber diameter in the range of 5 to 50 μm. The fiber length is preferably longer than the fiber length of the ultrafine fiber. As specific numerical values, short fibers cut to a length of 3 to 100 mm are preferable. Furthermore, 4-76 mm is preferable and it is especially preferable that it is the range of 5-64 mm.

  In the present invention, heat-bonding is performed in a state where the heat-adhesive short fibers intersect with each other by blending and heat-treating ultrafine short fibers having a fineness of less than 1 dtex and heat-adhesive short fibers having a fineness of 1 dtex or more. Thus, a fiber structure is formed in which the fixing points and the fixing points thermally bonded in a state where the heat-adhesive short fibers and the ultrafine short fibers intersect with each other are scattered.

  At this time, the blending of ultrafine short fibers having a fineness of less than 1 dtex needs to be in the range of 10 to 90% by weight. More preferably, it is preferably used in the range of 20 to 90% by weight in order to improve sound absorption performance and heat insulation performance. In the fiber structure of the present invention, it is possible to improve sound absorption performance and heat insulation performance by increasing the ratio of ultrafine short fibers. The blending of the heat-adhesive short fibers needs to be in the range of 5 to 50% by weight, more preferably 5 to 40% by weight. If the number of heat-bonded fibers is less than this range, the number of fixing points becomes extremely small, the handling is difficult, the fiber structure is not loose, and the moldability becomes poor. On the other hand, when the ratio of the heat-bonding composite short fibers is larger than this range, the number of bonding points becomes excessive, and the sound absorbing property is reduced due to the thickness reduction due to the heat shrinkage in the heat treatment step.

  Furthermore, in the fiber structure of the present invention, it is more preferable that the ultrafine short fibers are polyester short fibers. In particular, when the fiber structure of the present invention is used for a sound absorbing part such as a car, it is advantageous in joining with other polyester-based fiber-using structures or glass fiber-using structures constituting the car. Become. When an olefin ultrafine fiber type sound absorbing material is used, it is inferior in heat resistance as compared with a polyester type, and it is difficult to mold it together with a board-like structure. For this reason, the adhesive resin or the like is used to join the board-like structure in a separate process, but the use and process of the adhesive resin may be complicated. When the ultra-short fiber is a polyester-based short fiber, this step can be omitted, and furthermore, the heat resistance is high and it can be used for integral molding.

  Moreover, it is also preferable to add a colored fiber to the fiber structure of the present invention in addition to the ultrafine short fibers and the heat-bondable short fibers. In addition to the advantage that dirt is less noticeable, the mixed cotton state is easily judged from the appearance, which is preferable for maintaining the quality. In particular, it is preferable to use a fiber structure in which repellent fibers are mixed as colored fibers. Rebounded fiber collects used clothing and reuses it, contributing to reducing environmental impact.

The average density of such a fiber structure of the present invention needs to be less than 0.1 g / cm ³ . Furthermore, the range of 0.005 to 0.100 g / cm ³ is preferable. More ^preferably, it is preferable that ^{0.010g / cm 3 ~0.08g / cm 3} . If the average density exceeds 0.1 g / cm ³ , the fiber structure becomes plate-like and subsequent molding becomes difficult. In addition, the sound is likely to be reflected, and there is a possibility that it cannot be used as a sound-absorbing material, and it cannot be used for a vehicle or the like due to an increase in weight. On the other hand, when the density is too low, the bonding inside the fiber structure is weak and the handling tends to be difficult.

  Moreover, in the fiber structure of this invention, it is preferable that bulkiness does not change large at 200 degreeC or more. For example, it is preferable that the fiber structure containing ultrafine short fibers stays at 200 ° C. with a change of less than 30%, preferably less than 20%. In order to obtain such a fiber structure, it is possible to select a high resin as the melting point of the ultrafine fibers constituting the fiber structure, or as the melting point of components other than thermal adhesiveness by using the heat-adhesive short fibers as a composite fiber. preferable.

  In many cases, the fiber structure of the present invention is integrally molded together with other fiber structures, but when the bulkiness at 200 ° C. does not change significantly, the bulk hardly changes during integral molding. Since the thickness does not increase and the thickness does not decrease, the original sound absorption can be kept at a high level.

  Furthermore, it is also preferable that the fiber structure of the present invention is attached with another layer on one or both sides thereof. Thus, when using as a multilayer, the usage method of the dry nonwoven fabric which contains many ultrafine fibers for a surface layer, and the dry nonwoven fabric which contains few ultrafine fibers for a back surface layer is possible. Alternatively, it is also preferable to use a dry nonwoven fabric containing ultrafine fibers on the surface layer and a dry nonwoven fabric not containing ultrafine fibers on the back layer by means of heat bonding, an adhesive, a needle punch, or the like.

  And it is also preferable to stick | paste various layers other than the fiber structure of this invention to the fiber structure of this invention. For example, it is preferable to bond a nonwoven fabric by a direct spinning method such as spun bond, melt blown or flash bond.

  Further, the fiber structure of the present invention is preferably added with known functional processing such as water repellent processing, flameproof processing, flame retardant processing, and negative ion generation processing, or one or two surfaces of the fiber structure are heat treated. And it is also one of the preferable aspects to make the part high density.

  In order to obtain such a fiber structure of the present invention, it is preferable to first form a fiber web. Among these, a web manufacturing method using the air array method is preferable. For example, more specifically, it is a method in which two or more types of fibers are first weighed and mixed uniformly with a cotton blending facility, and then the fibers are opened. In this case, it is preferable to use a fiber spreader and spread the fibers uniformly at the same time, and the point is to use a pin cylinder or a metallic wire with a low density to open the fibers. However, when a high-density metallic wire or the like is used, the sinking of cotton into the wire, neps or the like occurs and the quality is lowered, and the productivity tends to be greatly lowered.

  Next, the mixed and spreaded constituent fibers are drawn together by an air flow, and converged by applying the air flow to a circumferential surface of a suction drum having a cylindrical shape on the surface, thereby forming a fiber web. At this time, on the peripheral surface of the suction drum, the base constituent fiber is sucked in a form in which the fibers are laminated obliquely at a portion where the constituent fiber is taken up. After that, the front and back layers are parallel to the belt by conveying the bundle of fibers collected by a conveyor having a belt and a roller, but in the intermediate layer, the fibers are oriented obliquely in the thickness direction. A fiber web accumulated in a state can be obtained.

  As a web forming apparatus suitable for such a web forming process by the air array method, for example, “V12 / R” manufactured by UTEFA or “RANDO-WEBBER” manufactured by RANDO is used. "(Registered trademark).

  Further, in order to obtain the fiber structure of the present invention, it is necessary to perform a heat bonding step in the step of bonding the fibers. In this heat-bonding process, heating is carried out at a temperature corresponding to the thermal characteristics of the heat-bondable short fibers while being sandwiched between a belt with no pressure or a breathable belt, and a known means such as a hot air circulating furnace or a heatable roll Thus, the fiber structure is obtained by heating the fibers and bonding the heat-adhesive short fibers to other constituent fibers.

  It is also possible to create a fiber structure by fully opening the blended cotton and then creating a web by a card method using a metallic wire for extra fine fibers, overlaying the web with a cross layer, and applying heat treatment. . It is also preferable to fabricate the fiber structure by performing a heat treatment while folding the web into an accordion shape (for example, “Struto equipment” manufactured by Struto Corporation may be used). Furthermore, it is also possible to carry out a needle punch in order to suppress surface fluff before heat treatment.

  Furthermore, by forming each constituent fiber in the fiber structure of the present invention three-dimensionally, a fiber structure (dry nonwoven fabric) more suitable for an object having a complicated shape is obtained. In particular, since cars and the like have complicated shapes, sound leaks from gaps and the like, but by using a dry nonwoven fabric that matches the shape, the characteristics of a dry nonwoven fabric can be fully exhibited. The method for three-dimensional molding is not particularly limited, but can be easily created by preheating the fiber structure to about 180 ° C., inserting the heated fiber structure into a normal temperature mold, and pressing it. .

  In order to make the configuration and effects of the present invention more specific, examples and the like will be given below, but the present invention is not limited to these examples. In addition, unless otherwise indicated, it shall represent a weight part, and each physical-property value in an Example and a comparative example was measured in accordance with the following method.

(1) Silicon content Samples of ultrafine fibers for dry nonwoven fabric were molded into tablets, and the front and back surfaces of the tablet were measured twice with a RIGAKU fluorescent X-ray measuring device (ZSX), and the average value was calculated. .

(2) Single yarn fineness It measured by the method as described in Japanese Industrial Standard JIS L 1015: 2005 8.5.1 Method A. That is, a small amount of the fiber sample is drawn in parallel with a hammer, and this is placed on Lasha paper placed on a cutting table. A gauge plate is pressure-bonded while a straight fiber sample is stretched with an appropriate force, and cut into a length of 30 mm with a blade such as a safety razor. Count 300 fibers as a set, weigh the mass, and determine the apparent fineness. From the apparent fineness and the equilibrium moisture content measured separately, the positive fineness is calculated by the following equation. The average value of the positive fineness was calculated five times.
F = [(100 + R ₀ ) / (100 + R _c )] × D
F: Positive fineness D: Apparent fineness R ₀ : Official moisture content (%) (value specified in Japanese Industrial Standard JIS L 0105 4.1)
R _c : equilibrium moisture content (%)

(3) Fiber length Measured by the method described in Japanese Industrial Standard JIS L 1015: 2005 8.4.1 Method A.

(4) Number of crimps The number of crimps was measured by the method described in Japanese Industrial Standard JIS L 1015: 2005 8.12.1.

(5) Intrinsic viscosity: [η]
A fiber (polyester polymer) sample (0.12 g) was dissolved in 10 mL of a tetrachloroethane / phenol mixed solvent (volume ratio 1/1), and the intrinsic viscosity (dL / g) at 35 ° C. was measured.

(6) Melt flow rate: MFR
The melt flow rate was measured according to Japanese Industrial Standard JIS K 7210 condition 4 (measurement temperature 190 ° C., load 21.18 N). The melt flow rate is a value measured using a polymer pellet immediately before melt spinning as a sample.

(7) Melting point Using a thermal differential analyzer model, measurement was performed at a temperature increase of 20 ° C./min to obtain a melting peak. If the melting temperature is not clearly observed, the melting point is defined as the temperature at which the polymer softens and starts to flow (softening point) using a trace melting point measuring device. In addition, the average value was calculated | required by n number 5.

(8) Fiber card passability Black polyester fibers obtained by kneading carbon particles having a round cross section of 2.2 dtex into white ultrafine fibers are laminated in two layers at a weight ratio of 70% and 30%, respectively, for a total of 50 g. did. After that, the cotton is passed through a pin cylinder type opening machine twice, and then the state of occurrence of nep when a fiber web is produced using a high-speed card testing machine manufactured by Ikegami Machinery Co., Ltd., and the resulting fiber web blended cotton Based on the situation, evaluation was made according to the following criteria. In addition, since the black polyester fiber was used, it became gray as a dry-type nonwoven fabric, and it was able to endure the practical use in which dirt is not easily visible.
A: The fiber easily passes through the card machine, there is no unopened fiber, and almost no nep is generated.
B: There seems to be no unopened fiber, but some nep is generated.
C: A web in which a large amount of nep is generated or unopened fibers remain.

(9) Thickness (mm) of fiber structure and sheet
It was measured according to JIS K6400.

(10) Density of fiber structure (g / cm ³ )
The density (g / cm ³ ) was determined by the following formula.
Density (g / cm ³ ) = Web weight (g / cm ² ) / Fibre structure thickness (cm)

(11) Sound absorption characteristics (sound absorption rate)
The sample is arranged so that the sheet-like material is located on the sound source side, and the sound absorption coefficient is the normal incident sound absorption coefficient according to JIS-A1405, which is a multi-channel analysis system 3550 type manufactured by Bruel & Kjar (software: BZ5087 type 2-channel analysis software) Measured by the 2-microphone method. The sound absorption rate was compared at 1000 Hz.

(12) Formability The film was hot drawn at 190 ° C. for 180 seconds and formed into a case having an inner diameter of 60 mm × height of 20 mm × thickness of 5 mm. The appearance of the case at the body was observed and evaluated according to the following criteria.
Grade 3: A beautiful case was created.
2nd grade: A little wrinkled but a case was created.
1st grade: A case cannot be made or there is a problem with the product.

[Example 1]
A polyethylene terephthalate (PET) chip containing 0.3% by weight of titanium dioxide and having an intrinsic viscosity of 0.47 dL / g is melted at 290 ° C. and discharged from a spinneret having 2504 round holes at a discharge rate of 340 g / min. This was taken up at a speed of 500 m / min to obtain a polyethylene terephthalate undrawn yarn having a single yarn fineness of 2.7 dtex. The unstretched yarns were aligned and stretched as a 163,000 decitex tow so that the total stretching ratio was 32.8 times in warm water. Thereafter, a polyoxyethylene copolymer polydimethylsiloxane oil was added as a component containing lauryl phosphate salt as a main component and silicon. Thereafter, crimping was applied using a push-in crimper box to obtain ultrafine short fibers for dry nonwoven fabric having a single yarn fineness of 0.06 dtex, a fiber length of 24 mm, and a crimp number of 17 / 25.4 mm.

  On the other hand, as a heat-bonding fiber, a core-sheath type polyester fiber (sheath component: low melting point PET [melting point 110 ° C.], core component: polyethylene terephthalate [melting point 256 ° C.]), fiber diameter 2.2 dtex, fiber length 51 mm, A heat-adhesive short fiber having a crimp number of 9 / 25.4 mm was prepared.

Black polyester fiber (fiber diameter 2.2 dtex, fiber length 51 mm, crimped number 10 / 25.4 mm) 30% by weight prepared by separately preparing 50% by mass of extra fine polyester fiber and 20% by mass of heat-adhesive short fiber After the cotton was mixed, it was mixed thoroughly with a mixing device and passed through a pin cylinder and a metallic wire cylinder to further improve the cotton mixing and fiber opening. Thereafter, a dry nonwoven fabric is prepared by the air lay method, and then a heat bonding process is performed in a hot air circulating furnace in which the temperature of the hot air having a net-like belt is set to 180 ° C., whereby the basis weight is 306 g / m ² and the thickness is 21 mm. A fiber structure (dry nonwoven fabric) having a density of 0.015 g / cm ³ was obtained. Table 1 shows the fiber characteristics and the moldability and sound absorption properties of the fiber structure (dry nonwoven fabric). Other preparation conditions and physical properties are also shown in Table 1.

[Example 2]
A fiber structure (dry nonwoven fabric) is obtained in the same manner as in Example 1 except that the single yarn fineness is 0.10 dtex, the cut length is 32 mm, and the crimp number is 14 / 25.4 mm. It was. The results are also shown in Table 1.

[Example 3]
A fiber structure was obtained in the same manner as in Example 1 except that the amount of dimethylpolysiloxane adhered to the ultrafine short fibers was 10 times. The results are also shown in Table 1.

[Example 4]
The ultra-fine short fibers, the heat-adhesive short fibers, and the black fibers are the same as those in Example 1, and the mixing ratio is changed to change the mixture ratio to 25 mass%, the ultra-adhesive short fibers 20 mass%, and the black fibers. After blending with 55% by weight of polyester fiber, a fiber structure having a basis weight of 487 g / m ² , a thickness of 11.0 mm, and a density of 0.05 g / cm ³ was obtained in the same manner as in Example 1. The fiber characteristics, the moldability of the fiber structure, and the sound absorption were measured. Other preparation conditions and physical properties are also shown in Table 1.

[Example 5]
As a non-woven skin A layer, 70 parts of polyethylene phthalate (PET) and 30 parts of polypropylene (PP) are melt-mixed with N ₂ gas as a foaming agent, extruded from an extruder at an extrusion temperature of 170 to 350 ° C., and rapidly cooled at the die outlet A take-off net-like atypical fiber sheet was obtained. On the other hand, a large number of polyester tow sheets of about 450,000 deniers were combined, bonded with an acrylic binder, spread at an overfeed of 2 times, and a spread ratio of 10 times, and heat-pressed to obtain a sheet having a basis weight of 70 g / m ² .

This sheet was inserted in front of the hot air circulating furnace in Example 4 and bonded to the web of Example 4, and heated and bonded in the hot air circulating furnace with the temperature of the hot air having a net-like belt set at 180 ° C. As a result, a fiber structure (dry nonwoven fabric) having a basis weight of 562 g / m ² , a thickness of 11.7 mm, and a density of 0.048 g / cm ³ was obtained. Table 2 shows the fiber characteristics and the moldability and sound absorption properties of the fiber structure (dry nonwoven fabric). The results are shown in Table 2.

[Comparative Example 1]
Ultrafine short fibers were obtained in the same manner as in Example 1 except that the amount of dimethylpolysiloxane adhered to the fibers in the stretching process was reduced. The amount of silicon contained in the fiber was 6 ppm. Other than that was carried out similarly to Example 1, and obtained the fiber structure. A large number of neps were confirmed on the surface of the produced fiber structure. The results are also shown in Table 2.

[Comparative Example 2]
A fiber structure was obtained in the same manner as in Example 1 except that the crimp to be applied by the push-in crimper box was adjusted and the number of crimps of the ultrafine short fiber was set to 8. Thereafter, in the same manner as in Example 4, a mixed cotton and fiber opening process was used to create a web by using a mixed card and a metallic card using an extra fine wire, and the web was overlapped by a cross layer. The production conditions are also shown in Table 2. However, a lot of ultra-fine fibers have fallen under the metallic card, and when the cross layer equipment web is moved from the metallic card equipment, the web was cut frequently. .

[Comparative Example 3]
TC3403 (product weight: 318 g / m ² , thickness = 30 mm) manufactured by Three M Co., Ltd. and trade name Thinsulate was prepared. This is composed of thick polyester fibers and PP meltblown fibers. When the fiber diameter was measured with an electron microscope, the PP meltblown fibers had a distribution of 0.5 to 15 μm, and the average value of 100 fibers was It was 3.3 μm. Moreover, when this cinsalate fiber was heat-molded in the same manner as in Example 1, the ultrafine fibers contained were fused, and a fiber structure with high sound absorption was not obtained. Table 2 shows the sound absorption rate of the cinsarate before heat molding.

Claims (7)

A fiber structure including an ultrafine short fiber having a fineness of less than 1 dtex and a heat-adhesive short fiber having a fineness of 1 dtex or more, wherein the ultrafine short fiber has a silicon content of 10 to 5000 ppm, a crimp number of 10 / 25.4 mm (1 inch). ) The above-mentioned fibers, wherein the heat-adhesive short fibers have a melting point 40 ° C. or more lower than the melting point of the ultrafine short fibers, the blending amount of the ultrafine short fibers is 10 to 90% by weight, and the blending amount of the thermoadhesive short fibers 5 to 50% by weight, and the fiber structure has an average density of 0.1 g / cm ³ or less.   The fiber structure according to claim 1, wherein the resin constituting the ultrafine short fiber is made of a polyester resin or a polyolefin resin.   The fiber structure according to claim 2, wherein the polyester resin is a polyalkylene terephthalate resin or a polyalkylene naphthalate resin.   The fiber structure according to claim 2, wherein the polyolefin resin is a polyethylene resin or a polyolefin resin.   The fiber structure according to any one of claims 1 to 4, wherein the number of crimps of the ultrafine short fibers is in the range of 12 / 25.4 mm to 36 / 25.4 mm.   The silicon in the ultrafine short fiber is derived from at least one of dimethylpolysiloxane, amino-modified polysiloxane, hydroxy-modified polysiloxane, and polyoxyethylene copolymerized polydimethylsiloxane. The fiber structure according to Item.   The fiber structure according to any one of claims 1 to 6, wherein the ultrafine short fiber has a melting point of 200 ° C or higher.