JP5719834B2 - Nonwoven fiber molded body and method for producing the same - Google Patents

Description

  The present invention relates to a non-woven fiber molded article that is lightweight and bulky, and excellent in breathability, heat insulation, durability, moldability, and recyclability, and a method for producing the same.

  Conventionally, a polystyrene foam (polystyrene foam) has been widely used as a lightweight material. Styrofoam is lightweight and excellent in heat insulation, moldability, and impact absorption, and is used as a buffer / packaging material and a heat insulation material that requires heat insulation / cooling. However, the foamed polystyrene does not recover its shape while being depressed when a local load is applied, or is easily broken when subjected to bending stress, and has low durability. In addition, when used as a shock-absorbing material for a helmet, it is easily stuffy because it is not breathable.

  As the cushion material, a flexible urethane foam is widely used because of its good texture and excellent shape stability. However, since a general flexible urethane foam is an independent foam, it does not have air permeability and is easily steamed. Moreover, it is easy to raise | generate weather resistance deterioration and yellowing, and its durability is also low. In terms of recycling, when it burns, it generates harmful NOx and CO, so it is not a material suitable for thermal recycling. As material recycling, a method of remolding a urethane chip obtained by crushing urethane foam waste material is used, but it is necessary to add a binder for connecting the crushed urethane.

Therefore, a non-woven fiber structure is obtained by laminating non-woven fiber webs containing wet heat adhesive fibers and heating them with high-temperature steam as a lightweight, breathable, durable, heat-insulating and folding-resistant material. A hard molded article having wet-heat adhesive fibers fused with a uniform adhesion rate in the thickness direction is known (Patent Document 1: International Publication WO 2007/116676). However, in this molded product, when the card web is wet-heat bonded with steam, the apparent density of the fiber assembly is increased, so that a molded product of 0.05 g / cm ³ or less cannot be obtained. In addition, since the web is sandwiched between two belt conveyors and molded, a board-shaped molded body can be created, but it is difficult to create a complicated three-dimensional structure.

  As a method of creating a three-dimensional structure with a fiber assembly, a method of filling a mold with a fiber material and a binder and performing thermoforming is known (Patent Document 2: JP 2000-238057 A). However, in this method, in order to adhere the fibers, it is necessary to fill the binder together, and it is difficult to uniformly adhere the binder to the fibers.

International Publication No. WO2007 / 116676 JP 2000-238057 A

  Accordingly, an object of the present invention is to provide a nonwoven fiber molded body having a nonwoven fiber structure, lightweight and bulky, excellent in moldability and capable of being easily molded even in a complicated three-dimensional shape, and a method for producing the same. There is to do.

  Another object of the present invention is to provide a non-woven fiber molded article excellent in recyclability and a method for producing the same.

  Still another object of the present invention is to provide a non-woven fiber molded article excellent in air permeability, heat insulation and durability and a method for producing the same.

  Another object of the present invention is to provide a non-woven fiber molded article that is lightweight, excellent in sound absorption, and excellent in form stability, and a method for producing the same.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that a non-woven fiber structure is obtained by fixing a plurality of non-woven fiber aggregates containing wet heat adhesive fibers by fusion of the wet heat adhesive fibers. The present invention was completed by discovering that it is lightweight and bulky, has excellent moldability, and can be easily molded even with complicated three-dimensional shapes.

That is, the nonwoven fiber molded body of the present invention is a nonwoven fiber molded body formed of a plurality of nonwoven fiber aggregates, wherein the nonwoven fiber aggregates include wet heat adhesive fibers, and the nonwoven fabrics. The fiber aggregates are fixed by fusing the wet heat adhesive fibers. The apparent density of the molded body may be about 0.01 to 0.7 g / cm ³ . The non-woven fiber assembly may have fibers fixed by fusion of wet heat adhesive fibers. In the nonwoven fiber molded body of the present invention, the nonwoven fiber aggregate may have an indefinite shape, and the number ratio of wet heat adhesive fibers on the aggregate surface may be 50% or more. Moreover, the said nonwoven fiber assembly may be anisotropic and each nonwoven fiber assembly may be oriented in the random direction. The non-woven fiber assembly may be a non-woven fiber assembly in which fibers are fixed by fusion of wet heat adhesive fibers or a waste material of a molded body obtained from the non-woven fiber assembly. The volume of the nonwoven fiber assembly may be about 0.01 to 300 cm ³ .

The nonwoven fiber molded body of the present invention has an apparent density of about 0.01 to 0.05 g / cm ³ and an air permeability according to the fragile method of about 0.1 to 300 cm ³ / (cm ² · sec). In addition, the thermal conductivity may be about 0.03 to 0.1 W / m · K.

  The non-woven fiber aggregate may be formed of wet heat adhesive fibers alone, and can be selected from the range of wet heat adhesive fibers / non-wet heat adhesive fibers = 10/90 to 100/0. The non-woven fiber assembly may further contain non-wet heat adhesive fibers, and the ratio (mass ratio) between the wet heat adhesive fibers and the non-wet heat bond fibers is determined as wet heat bond fibers / non-humid heat bond fibers. = 10 / 90-99 / 1 may be sufficient.

  The wet heat adhesive fiber is formed of an ethylene-vinyl alcohol copolymer having an ethylene unit content of 10 to 60 mol% and a non-wet heat adhesive resin, and the non-wet heat adhesive property is bonded to the ethylene-vinyl alcohol copolymer. The ratio (mass ratio) with the resin is the former / the latter = 90/10 to 10/90, and the ethylene-vinyl alcohol copolymer has at least a part of the wet heat adhesive fiber surface in the length direction. You may occupy continuously. In particular, the wet heat adhesive fiber is composed of a sheath part made of wet heat adhesive resin and at least one non-wet heat adhesive resin selected from the group consisting of polypropylene resin, polyester resin and polyamide resin. The core-sheath composite fiber formed with the core part made may be sufficient.

  In the nonwoven fiber molded body of the present invention, the nonwoven fiber assemblies may be thermally bonded using high-temperature steam.

  The present invention also includes a method for producing the molded body, which includes a step of thermally bonding a plurality of nonwoven fiber assemblies. The thermal bonding may be thermal bonding using high-temperature steam.

  In the present invention, since a plurality of nonwoven fiber aggregates containing wet heat adhesive fibers are fixed by fusion of the wet heat adhesive fibers, they have a nonwoven fiber structure, are light and bulky, and have good moldability. Excellent and complex 3D shapes can be easily formed. In addition, as a nonwoven fiber aggregate, waste material of the nonwoven fiber aggregate, for example, a piece generated in the manufacturing process, an aggregate obtained by crushing or cutting waste or a used nonwoven fiber aggregate, etc. Because it can, it is excellent in recyclability. Furthermore, since it has a non-woven fiber structure, air permeability, heat insulation, and durability can be improved. In addition, it is lightweight and excellent in sound absorption, and the form stability (or independence) can be improved.

FIG. 1 is a schematic view showing an example of a nonwoven fiber molded body of the present invention in which a nonwoven fiber assembly is regularly oriented. FIG. 2 is a schematic perspective view showing an example of the nonwoven fiber molded body of the present invention in which the nonwoven fiber aggregate is oriented in a random direction. FIG. 3 is a schematic perspective view showing another example of the nonwoven fiber molded body of the present invention in which the nonwoven fiber aggregate is oriented in a random direction. FIG. 4 is a schematic view of an example of a steam press molding machine used in the production method of the present invention. FIG. 5 is a graph showing the sound absorption rate with respect to the frequency of the sound absorbers obtained in Example 3 and Comparative Example 4.

[Nonwoven fiber assembly]
In the present invention, a plurality of non-woven fiber aggregates (non-woven fiber aggregate units or granular non-woven fiber aggregates) are bonded to each other at a contact portion between the aggregates. In order to form the dots, it is possible to produce a molded body that is bulky and lightweight as a whole.

(Wet heat adhesive fiber)
The wet heat adhesive fiber is composed of at least a wet heat adhesive resin. The wet heat adhesive resin only needs to be able to flow or easily deform at a temperature that can be easily realized by high-temperature steam and to exhibit an adhesive function. Specifically, a thermoplastic resin that is softened with hot water (for example, about 80 to 120 ° C., particularly about 95 to 100 ° C.) and can be self-adhered or bonded to other fibers, for example, a cellulose-based resin (C such as methylcellulose) _1-3 alkylcelluloses, hydroxyalkyl C _1-3 alkyl celluloses such as hydroxypropyl cellulose, carboxy C _1-3 alkyl cellulose or a salt thereof, such as carboxymethyl cellulose), polyalkylene glycol resin (polyethylene oxide, poly C ₂ such as polypropylene oxide _-4 alkylene oxide), polyvinyl resins (polyvinyl pyrrolidone, polyvinyl ether, vinyl alcohol polymers, polyvinyl acetals, etc.), acrylic copolymers and their salts [(meth) acrylic acid, (meth) acrylamids A copolymer containing a unit composed of an acrylic monomer such as an alkyl group or an alkali metal salt thereof], a modified vinyl copolymer (a vinyl monomer such as isobutylene, styrene, ethylene or vinyl ether, and anhydrous A copolymer with an unsaturated carboxylic acid such as maleic acid or an anhydride thereof or a salt thereof), a polymer having a hydrophilic substituent (polyester, polyamide having a sulfonic acid group, a carboxyl group or a hydroxyl group introduced, Polystyrene or a salt thereof), aliphatic polyester resin (polylactic acid resin, etc.), and the like. Furthermore, among polyolefin resins, polyester resins, polyamide resins, polyurethane resins, thermoplastic elastomers or rubbers (such as styrene elastomers), it can be softened at the temperature of hot water (high-temperature steam) to exhibit an adhesive function. Other resins are also included.

These wet heat adhesive resins can be used alone or in combination of two or more. The wet heat adhesive resin is usually composed of a hydrophilic polymer or a water-soluble resin. Among these wet heat adhesive resins, vinyl alcohol polymers such as ethylene-vinyl alcohol copolymers, polylactic acid resins such as polylactic acid, (meth) acrylic copolymers containing (meth) acrylamide units, A vinyl alcohol polymer containing an α-C _2-10 olefin unit such as ethylene or propylene, particularly an ethylene-vinyl alcohol copolymer is preferred.

  In the ethylene-vinyl alcohol copolymer, the ethylene unit content (copolymerization ratio) is, for example, about 10 to 60 mol%, preferably about 20 to 55 mol%, and more preferably about 30 to 50 mol%. When the ethylene unit is in this range, a unique property of having wet heat adhesiveness but not hot water solubility is obtained. If the proportion of the ethylene units is too small, the ethylene-vinyl alcohol copolymer easily swells or gels with low-temperature steam (water), and its form is likely to change only once wetted with water. On the other hand, when the ratio of the ethylene unit is too large, the hygroscopicity is lowered, and fiber fusion due to wet heat is difficult to be exhibited, so that it is difficult to ensure practical strength. When the ratio of the ethylene unit is particularly in the range of 30 to 50 mol%, the workability is particularly excellent.

  The saponification degree of the vinyl alcohol unit in the ethylene-vinyl alcohol copolymer is, for example, about 90 to 99.99 mol%, preferably 95 to 99.98 mol%, more preferably 96 to 99.97 mol%. Degree. When the degree of saponification is too small, the thermal stability is lowered, and the stability is lowered by thermal decomposition or gelation. On the other hand, if the degree of saponification is too large, it is difficult to produce the fiber itself.

  Although the viscosity average degree of polymerization of an ethylene-vinyl alcohol-type copolymer can be selected as needed, it is 200-2500, for example, Preferably it is 300-2000, More preferably, it is about 400-1500. When the degree of polymerization is within this range, the balance between spinnability and wet heat adhesion is excellent.

  The cross-sectional shape (cross-sectional shape perpendicular to the length direction of the fiber) of the wet heat-adhesive fiber is round or irregular (flat, elliptical, polygonal, 3-14 leaf, T-shaped, H-shaped , V-shape, dogbone (I-shape, etc.)], and may be a hollow cross-section.

  The wet heat adhesive fiber may be a composite fiber composed of a plurality of resins including at least a wet heat adhesive resin. It is sufficient that the wet heat-adhesive fiber has at least part of the wet-heat adhesive resin on the fiber surface, but the wet heat-adhesive resin has at least a part of the surface in the length direction from the viewpoint of adhesiveness. It is preferable to occupy continuously. The coverage of the wet heat adhesive resin is, for example, 50% or more, preferably 80% or more, and more preferably 90% or more.

  The cross-sectional structure of the composite fiber in which the wet heat adhesive fiber occupies the surface includes a concentric core-sheath type, an eccentric core-sheath type, a side-by-side type, a sea-island type, a multilayer bonding type, a radial bonding type, and a random composite type. Can be mentioned. Among these cross-sectional structures, the core-sheath structure (that is, the sheath part is wet-heat-adhesive, which is a structure in which the wet-heat adhesive resin occupies the entire surface continuously in the length direction because it is a highly adhesive structure. A core-sheath structure made of resin is preferred.

  In the case of a composite fiber, wet heat adhesive resins may be combined with each other, but may be combined with non-wet heat adhesive resins. Non-wet heat adhesive resins include water-insoluble or hydrophobic resins such as polyolefin resins, (meth) acrylic resins, vinyl chloride resins, styrene resins, polyester resins, polyamide resins, polycarbonate resins, Examples include polyurethane resins and thermoplastic elastomers. These non-wet heat adhesive resins can be used alone or in combination of two or more.

  Among these non-wet heat adhesive resins, from the viewpoint of heat resistance and dimensional stability, resins having a melting point higher than that of wet heat adhesive resins (particularly ethylene-vinyl alcohol copolymers), such as polypropylene resins and polyester resins. Resins and polyamide resins, particularly polyester resins and polyamide resins are preferred from the standpoint of excellent balance between heat resistance and fiber-forming properties.

Polyester resins include aromatic polyester resins such as poly C _2-4 alkylene arylate resins (polyethylene terephthalate (PET), polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), especially polyethylene such as PET. A terephthalate resin is preferred. In addition to the ethylene terephthalate unit, the polyethylene terephthalate resin is not limited to other dicarboxylic acids (for example, isophthalic acid, naphthalene-2,6-dicarboxylic acid, phthalic acid, 4,4'-diphenyldicarboxylic acid, bis (carboxyphenyl) ethane. , 5-sodium sulfoisophthalic acid, etc.) and diols (for example, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexane-1,4-dimethanol, Units composed of polyethylene glycol, polytetramethylene glycol, etc.) may be included at a ratio of about 20 mol% or less.

  Polyamide resins include polyamides 6, polyamides 66, polyamides 610, polyamides 10, polyamides 12, polyamides 6-12 and other aliphatic polyamides and copolymers thereof, half-synthesized from aromatic dicarboxylic acids and aliphatic diamines. Aromatic polyamide is preferred. These polyamide-based resins may also contain other copolymerizable units.

  The ratio (mass ratio) of the wet heat adhesive resin and the non-wet heat adhesive resin (fiber-forming polymer) can be selected according to the structure (for example, core-sheath structure), and if the wet heat adhesive resin is present on the surface Although not particularly limited, for example, wet heat adhesive resin / non-wet heat adhesive resin = 90/10 to 10/90, preferably 80/20 to 15/85, and more preferably about 60/40 to 20/80. If the proportion of wet heat adhesive resin is too large, it will be difficult to ensure the strength of the fiber, and if the proportion of wet heat adhesive resin is too small, it will be difficult to have the wet heat adhesive resin continuously in the length direction of the fiber surface. Thus, the wet heat adhesiveness is lowered. This tendency is the same when the wet heat adhesive resin is coated on the surface of the non-wet heat adhesive resin.

  The average fineness of the wet heat adhesive fiber can be selected, for example, from the range of about 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. Degree. When the average fineness is in this range, the balance between the strength of the fiber and the expression of wet heat adhesion is excellent.

The average fiber length of the wet heat adhesive fiber can be selected from a range of about 10 to 100 mm, for example,
Preferably it is 20-80 mm, More preferably, it is about 25-75 mm (especially 35-55 mm). When the average fiber length is within this range, the fibers are sufficiently entangled, so that the mechanical strength of the fiber assembly is improved. On the other hand, if the fiber length is too long, it is difficult to form a non-woven fiber assembly having a uniform basis weight.

  The crimp rate of the wet heat adhesive fiber is, for example, about 1 to 50%, preferably 3 to 40%, more preferably about 5 to 30% (particularly 10 to 20%). The number of crimps is, for example, about 1 to 100 pieces / 25 mm, preferably about 5 to 50 pieces / 25 mm, and more preferably about 10 to 30 pieces / 25 mm. The number of crimps after heating is, for example, 5 pieces / 25 mm or more (for example, 5 to 200 pieces / 25 mm), preferably 5 to 150 pieces / 25 mm, and more preferably about 10 to 100 pieces / 25 mm. Also good. In the present invention, the adhesiveness between the aggregate units can be improved by crimping the wet heat adhesive fibers.

  In addition to these fibers, the nonwoven fiber assembly may contain other fibers as long as the properties of the fibers are not impaired. Examples of other fibers include non-wet heat adhesive resins exemplified in the section of wet heat adhesive fibers, cellulosic fibers [eg, natural fibers (cotton, wool, silk, hemp, etc.), semisynthetic fibers (triacetate). Acetate fiber such as fiber), regenerated fiber (rayon, polynosic, cupra, lyocell (for example, registered trademark name: “Tencel”, etc.)), inorganic fiber (for example, carbon fiber, glass fiber, metal fiber, etc.) Etc. can be used. The average fineness and average fiber length of the other fibers are the same as those of the wet heat adhesive fibers. These other fibers can be used alone or in combination of two or more.

  Of these other fibers, regenerated fibers such as rayon, semi-synthetic fibers such as acetate, polyolefin fibers such as polypropylene and polyethylene, polyester fibers, and polyamide fibers are preferable. In particular, when the wet heat adhesive fiber is a polyester fiber, the other fiber may also be a polyester fiber.

  The ratio of the wet heat adhesive fiber is, for example, 10% by mass or more, preferably 30% by mass or more with respect to the entire nonwoven fiber assembly. In particular, from the viewpoint of adhesion between the nonwoven fiber aggregate units, the number ratio of wet heat adhesive fibers on the aggregate surface may be 30% or more, for example, 50% or more, preferably 70% or more, and more preferably. May be 90% or more.

  Nonwoven fiber aggregates are further made of conventional additives such as stabilizers (heat stabilizers such as copper compounds, UV absorbers, light stabilizers, antioxidants, etc.), antibacterial agents, deodorants, fragrances, It may contain a colorant (such as a dye / pigment), a filler, an antistatic agent, a flame retardant, a plasticizer, a lubricant, and a crystallization rate retarder. These additives can be used alone or in combination of two or more. These additives may be carried on the surface of the fiber or may be contained in the fiber.

(Characteristics of non-woven fiber assembly)
The non-woven fiber assembly (granular or block-like non-woven fiber assembly) has a non-woven fiber structure formed of at least wet heat adhesive fibers.

  Further, in the nonwoven fiber molded body of the present invention, in order to obtain a nonwoven fiber structure having bulkiness and breathability, the fiber is formed by fusing wet heat adhesive fibers in the internal shape of the nonwoven fiber assembly. It is necessary to adjust the adhesion state of the material appropriately.

  Specifically, the non-woven fiber assembly is fused at the intersections of the wet heat adhesive fibers or other fibers (that is, the intersection of the wet heat adhesive fibers, the intersection of the wet heat adhesive fibers and the other fibers). It is preferable. In the present invention, in the non-woven fiber assembly, the fibers constituting the non-woven fiber structure are bonded at the contact points of each fiber by wet heat adhesive fibers, but the form of the fiber assembly is formed with as few contacts as possible. In order to hold, it is preferable that the adhesion points are distributed substantially uniformly from the vicinity of the surface of the assembly to the inside thereof.

  When the adhesion points are concentrated on the surface or inside, the shape stability in a portion having few adhesion points is lowered. For example, a bulky nonwoven fiber assembly obtained by the thermal bond method has a portion close to the heat source that is excessively bonded and the surface is cured, but the interior far from the heat source has few bonding points and the form is not stable. Moreover, since an excessive heat history is given to a fiber in forming an adhesion point, it becomes impossible to adhere | attach non-woven fiber aggregates again.

  On the other hand, in the non-woven fiber assembly, the adhesion points are distributed almost uniformly from the vicinity of the surface of the assembly to the inside, and the fibers are efficiently fixed. In spite of the small amount, the form stability can be expressed, and both bulkiness and air permeability can be achieved. Further, since the fibers are fused by the wet heat adhesive fibers, the fibers can be prevented from falling off, and the structure is hardly damaged. In addition, since it is softened and bonded with water vapor at about 100 to 120 ° C., the wet heat adhesive fibers do not receive an excessive heat history, so that the heat treatment is performed once for the production of the non-woven fiber assembly. It is possible to bond the nonwoven fiber assemblies again.

  Further, in the non-woven fiber assembly, not only fusion by wet heat adhesive fibers is uniformly dispersed and point-bonded, but also the point-bond distance of these points is short (for example, several tens to several hundreds μm). ) In the network structure. By forming a molded body from a non-woven fiber assembly having such a structure, the molded body of the present invention has high followability to strain even when an external force is applied, and finely dispersed fibers. Since the external force is dispersed and reduced at each fusion point, it can be estimated that high form stability is expressed.

The apparent density of the non-woven fiber aggregate can be selected depending on the application, and is, for example, 0.05 to 0.7 g / cm ³ , preferably 0.08 to 0.5 g / cm ³ , more preferably 0.1 to 0.1 g / cm ³ . It is about 0.4 g / cm ³ . In particular, when producing a hard molded body, the apparent density is 0.2 to 0.7 g / cm ³ , preferably 0.25 to 0.65 g / cm ³ , more preferably 0.3 to 0.6 g / cm ³ . ^It may be about ³ . In the case of manufacturing a shaped body of a soft, apparent density 0.05 to 0.5 g / cm ^3, preferably 0.08~0.4g / cm ^3, more preferably 0.1~0.35g / cm ^It may be about ³ . If the density is too small, it is difficult to produce by the current production method, and productivity is lowered. On the other hand, when the density is too large, lightness and air permeability are lowered.

The basis weight of the non-woven fiber aggregate can be selected, for example, from a range of about 50 to 10000 g / m ² , preferably 100 to 8000 g / m ² , more preferably about 200 to 6000 g / m ² . If the basis weight is too small, it is difficult to ensure the hardness. If the basis weight is too large, the web is too thick and high-temperature steam cannot sufficiently enter the inside of the web in wet heat processing, and the structure is uniform in the thickness direction. It becomes difficult to make a body.

The air permeability of the nonwoven fiber aggregate by the Frazier method is 0.1 cm ³ / (cm ² · sec) or more [eg, 0.1 to 300 cm ³ / (cm ² · sec)], preferably 1 to 250 cm ³ / (Cm ² · sec), more preferably about 5 to ²⁰⁰ cm ³ / (cm ² · sec). If the air permeability is too small, it becomes difficult for high-temperature steam or hot air to reach the inside, making it difficult to produce a molded article. On the other hand, if the air permeability is too high, the air permeability becomes high, but the fiber voids inside the aggregate become too large, and the form stability is lowered.

  In the non-woven fiber assembly, the fiber constituting the non-woven fiber structure can be selected from a range of about 1 to 85% by the fusion of the wet heat adhesive fibers. It is 85%, preferably 20 to 80%, more preferably about 30 to 75%. Moreover, in a soft molded object, it is 1 to 60%, for example, Preferably it is 2 to 50%, More preferably, it is about 3 to 35% (especially 3 to 30%) grade. Furthermore, the non-woven fiber assembly has a ratio of the minimum value to the maximum value of the fiber adhesion rate in each region divided into three equal parts in the thickness direction (minimum value / maximum value) (the minimum region with respect to the region with the maximum fiber adhesion rate). The ratio is, for example, about 50% or more (for example, 50 to 100%), preferably about 55 to 99%, more preferably about 60 to 98% (particularly 70 to 97%). May be. The fiber adhesion rate and the uniformity thereof can be calculated based on the ratio of the number of cross sections of two or more fibers bonded to the total number of cross sections of all the fibers in the non-woven fiber cross section. International Publication WO 2007/116676 (Patent Document) It can be measured by the method described in 1).

The volume of the nonwoven fiber aggregate may be selected from the range of 0.01～300Cm ^3, preferably, 0.1～100Cm ^3, more preferably a 0.5~50cm ^3. Volume 0.01 cm ³ less than the density of the nonwoven fiber aggregate becomes difficult to create a 0.05 g / cm ³ or less of low density molded body, filling the larger 300 cm ^3, the aggregation into a mold When molding, it becomes impossible to fill uniformly.

  The shape of the non-woven fiber assembly is anisotropic such as isotropic shape such as spherical shape, dice shape, rod shape (prism column shape, cylindrical shape, etc.), plate shape or sheet shape, cone shape, pyramid shape, block shape, irregular shape, etc. It may be a shape or the like. Among these shapes, an anisotropic shape such as an indefinite shape, a rod shape, a plate shape, or a sheet shape is preferable from the viewpoint of the stability of the molded body. Further, the shape of each aggregate may be the same or different.

  The size of the non-woven fiber aggregate can be selected according to the target molded body, but can be selected from a range of, for example, an average diameter of about 1 to 500 mm, preferably 2 to 100 mm, more preferably 3 to 50 mm (particularly 5 to 5 mm). 30 mm).

  In particular, in the case of a rod, for example, the major axis is 3 to 100 mm, preferably 5 to 80 mm, more preferably about 10 to 50 mm (especially 15 to 40 mm), and the average diameter of the cross section is 0.1 to 50 mm, preferably 0. It is about 5-30 mm, More preferably, it is about 1-20 mm (especially 3-10 mm).

  In the case of a plate shape or a sheet shape, for example, the average diameter of the planar shape is 5 to 300 mm, preferably 10 to 200 mm, more preferably 15 to 100 mm (particularly 20 to 80 mm), and the thickness is 0.1 to 30 mm. The thickness is preferably about 0.3 to 20 mm, more preferably about 0.5 to 15 mm (particularly 1 to 10 mm).

  The size of each aggregate may be the same as or different from the shape.

The ratio (mass ratio) of the wet heat adhesive fiber and the non-wet heat adhesive fiber in the nonwoven fiber assembly is wet heat adhesive fiber / non-wet heat adhesive fiber = 10/90 to 100/0 (for example, 10/90 to 99). / 1), preferably 30/70 to 100/0 (for example, 30/70 to 95/5), more preferably about 50/50 to 100/0 (for example, 50/50 to 90/10). is there. When the ratio of the wet heat adhesive fibers is too small, the shape of the fiber aggregate tends to collapse. From the point which can improve adhesion | attachment of a nonwoven fiber assembly unit, wet heat adhesive fiber / non-humid heat adhesive fiber = 70 / 30-100 / 0, Preferably it is 80 / 20-100 / 0, More preferably, it is 90/10 It may be about ~ 100/0, and may be formed of wet heat adhesive fibers alone.

  The nonwoven fiber assembly may further include crimped fibers. The crimped fiber may be a composite fiber in which a plurality of resins having different heat shrinkage rates form a phase separation structure. For example, JP 2009-97133 A, JP 2009-183363 A, and JP 2010- No. 84284 is disclosed, and crimped fibers can be used. The ratio of the crimped fibers may be 50% by mass or less, preferably 1 to 40% by mass, and more preferably about 5 to 30% by mass with respect to the entire nonwoven fiber assembly.

[Nonwoven fiber molded body]
The nonwoven fiber molded body of the present invention is formed by combining a plurality of the nonwoven fiber aggregate units, and the molded body is formed by wet-heat bonding the nonwoven fiber aggregate units. The orientation of each non-woven fiber aggregate (particularly the orientation of the anisotropically shaped aggregate) is not particularly limited, and may be regularly or randomly oriented. The nonwoven fiber molded body of the present invention may have voids between the nonwoven fiber aggregates, and in particular may have voids penetrating the molded body. It is preferable that the bodies are in close contact with each other. Particularly, in the case of a hard molded body, it is preferable that the units are closely bonded to each other and do not have a void portion penetrating the molded body.

  FIG. 1 is a schematic view showing an example of a nonwoven fiber molded body of the present invention in which a nonwoven fiber assembly is regularly oriented. This non-woven fiber molded body 1 is formed by combining a plurality of non-woven fiber assemblies having a rod shape with a substantially rectangular cross section, and the main non-woven fiber assembly 2 is oriented with its longitudinal direction parallel to the surface direction. The non-woven fiber assemblies 3 are arranged with their longitudinal directions oriented perpendicular to the plane direction at a predetermined interval. In this molded body, the rod-shaped assembly having the longitudinal direction oriented perpendicular to the surface direction is present at an appropriate interval with respect to the rod-shaped assembly having the longitudinal direction oriented parallel to the surface direction. The body is bonded in a balanced manner in the surface direction and the thickness direction, and the molded body has a uniform strength.

  FIG. 2 is a schematic perspective view showing an example of the nonwoven fiber molded body of the present invention in which the nonwoven fiber aggregate is randomly oriented. This non-woven fiber molded body 11 is formed by combining a plurality of non-woven fiber assemblies 12 each having a rod shape with a substantially square cross section, and each non-woven fiber assembly 12 is arranged in a random direction. ing. In this molded product, the non-woven nonwoven fiber aggregates are oriented in random directions, so that the non-woven fiber aggregates are arranged in various directions, so that the adhesion points between the aggregates are moderate. Are uniformly dispersed at intervals, and moderate voids are formed inside the molded body. Therefore, such a molded body is excellent in lightness and air permeability. Furthermore, uniform strength and folding resistance can be exhibited by the random orientation of the rod-like aggregate.

  FIG. 3 is a schematic perspective view showing another example of the nonwoven fiber molded body of the present invention in which the nonwoven fiber aggregates are randomly oriented. This non-woven fiber molded body 21 is formed by combining a plurality of non-woven fiber aggregates 22 whose planar shape is a plate-like shape, and each non-woven fiber aggregate 22 is arranged in a random direction. Has been. This non-woven fiber assembly is soft, and the non-woven fiber assembly includes an assembly bonded to another assembly in a folded state. In this molded body, the plate-like non-woven fiber assembly is in surface contact, so that it is flexible but has excellent integration as a molded body. Such a molded body is excellent in cushioning properties and is not easily separated and can maintain the integrity, and thus is suitable for uses such as futon cotton.

  Among these molded products, when the shape of the nonwoven fiber assembly is an anisotropic shape, each nonwoven fiber assembly has high productivity and high uniformity in lightness and strength of the molded product. A molded body oriented in a random direction is preferred.

(Characteristics of non-woven fiber molding)
Furthermore, in order to make the nonwoven fiber molded body of the present invention into a molded body having bulkiness, breathability, durability, and moldability, in the internal shape of the molded body, the nonwoven fiber aggregates are fused together. The adhesion state needs to be adjusted appropriately.

  The non-woven fiber molded product of the present invention is an intersection (that is, non-woven fiber aggregate) between the non-woven fiber aggregate units or other structural units (fiber aggregate or granular material not including wet heat adhesive fibers). And the non-woven fiber aggregate and other structural units) are preferably fused and bonded. Since each non-woven fiber assembly unit is fused, the non-woven fiber assembly can be prevented from falling off, and the structure is not easily destroyed. In addition, since the non-woven fiber aggregates do not receive an excessive heat history because they are softened and bonded with water vapor at about 100 to 120 ° C., the non-woven fiber aggregates can be bonded again and recycled. Excellent.

Adhesion point area between non-woven fiber aggregates (when one non-woven fiber aggregate unit is bonded to an adjacent non-woven fiber aggregate unit or other constituent units at a plurality of locations, each adhesion point area) Is 0.1 to 100 cm ² , preferably 1 to 10 cm ² , more preferably 1 to 5 cm ² . If the adhesion area is smaller than 0.1 cm ² , the structure is easily destroyed when subjected to an external force, and if it is larger than 100 cm ² , the moldability is lost, so that a complicated three-dimensional structure cannot be formed.

Specifically, the apparent density of the nonwoven fiber molded body of the present invention can be selected from a range of about 0.01 to 0.7 g / cm ³ , for example, 0.02 to 0.4 g / cm 2. cm ³ , preferably 0.05 to 0.4 g / cm ³ , more preferably about 0.07 to 0.3 g / cm ³ . If the apparent density is too low, the air permeability is improved, but the form stability is lowered. On the other hand, if the apparent density is too high, the form stability can be ensured, but the air permeability is lowered and the lightness is impaired. In the present invention, it is possible to maintain the form of the molded body with relatively low density by fusion with high uniformity.

Furthermore, as described above, each non-woven fiber assembly is difficult to prepare a molded body of 0.05 g / cm ³ or less due to manufacturing restrictions. By molding by combining the nonwoven fiber aggregate units, it is possible to prepare a low-density molded article that could not be achieved by conventional nonwoven fiber aggregates. That is, the apparent density of the nonwoven fiber molded body of the present invention may be a low density of about 0.01 to 0.05 g / cm ³ , for example.

Since the nonwoven fiber molded body of the present invention has a nonwoven fiber structure, it has voids formed between the fibers. Unlike the resin foam such as sponge, these voids are not independent voids but are continuous, and thus have air permeability. The air permeability of the molded article 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 in terms of air permeability according to the Frazier method. 0.5 to 250 cm ³ / (cm ² · sec) (for example, 1 to 250 cm ³ / (cm ² · sec)), more preferably about 5 to ²⁰⁰ cm ³ / (cm ² · sec), It is about 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 molded body, making it difficult for natural air to enter and exit. On the other hand, if the air permeability is too high, the air permeability becomes high, but the fiber voids in the molded body become too large, and the form stability is lowered.

  The nonwoven fiber molded body of the present invention 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 It is about 0.08 W / m · K.

In addition to the non-woven fiber aggregate, the non-woven fiber aggregate of the present invention includes other constituent units or constituent materials (or granular materials) as long as the characteristics of the non-woven fiber aggregate are not impaired. Also good. Examples of other structural units include fiber aggregates (for example, non-woven fiber aggregates) that are made of non-wet heat adhesive fibers and do not contain wet heat adhesive fibers. The proportion of the other structural unit may be 10% by weight or less (particularly 5% by weight or less) with respect to the entire molded body. In the nonwoven fiber molded body of the present invention, the conventional additives exemplified in the section of the nonwoven fiber aggregate may be blended together with the nonwoven fiber aggregate.

  Since the shape of the nonwoven fiber molded body of the present invention is formed by combining a plurality of nonwoven fiber assemblies, it is not limited to a two-dimensional shape such as a sheet shape or a plate shape, and can be shaped into various three-dimensional shapes.

[Method for producing nonwoven fiber molded body]
The method for producing a nonwoven fiber molded body of the present invention includes a step of thermally bonding a plurality of nonwoven fiber assemblies. The method of the present invention may further include a forming step of forming a nonwoven fiber assembly.

(Molding process of non-woven fiber assembly)
In the forming process of the nonwoven fiber assembly, first, the fiber containing the wet heat adhesive fiber is formed into a web. As a method for forming the web, a conventional method, for example, a direct method such as a spun bond method or a melt blow method, a card method using melt blow fibers or staple fibers, a dry method such as an air array method, or the like can be used. Among these methods, a card method using melt blown fibers or staple fibers, particularly a card method using staple fibers is widely used. Examples of the web obtained using staple fibers include a random web, a semi-random web, a parallel web, and a cross-wrap web.

  Next, the obtained fiber web is sent to the next process by a belt conveyor, heat-treated with high-temperature steam, and the wet heat adhesive fibers are fused. In the present invention, by using a method of treating with high-temperature steam as the heating method, uniform fusion can be expressed from the surface to the inside of the fiber assembly. In addition, as a pre-process of the fusion process, a part of the fibers of the obtained fiber web is made from low-pressure water (for example, 0.1 to 1.5 MPa, preferably from the viewpoint of suppressing the scattering of the fibers. A step of slightly entanglement may be performed by a method of entanglement by spraying or spraying (spraying) water (about 0.5 to 1 MPa).

  Specifically, the obtained fiber web is sent to the next process by a belt conveyor, and then exposed to a superheated or high-temperature steam (high-pressure steam) stream to obtain a fiber assembly having a non-woven fiber structure. That is, when the fiber web transported by the belt conveyor passes through the high-speed and high-temperature steam flow ejected from the nozzle of the steam spraying device, the wet heat adhesive fibers are fused by the sprayed high-temperature steam. In particular, since the fiber web in the present invention has air permeability, high-temperature water vapor penetrates into the inside, and a fiber assembly having a substantially uniform structure can be obtained.

  The belt conveyor to be used is not particularly limited as long as it can be subjected to high temperature steam treatment without disturbing the form of the fiber web used for processing, and an endless conveyor is preferably used. In addition, a general independent belt conveyor may be used, and another belt conveyor may be combined as necessary, and the web may be transported with the web sandwiched between both belts. By conveying in this way, when processing a fiber web, it can suppress that the form of the fiber web conveyed by external force, such as the water used for a process, high temperature steam, and a conveyor's vibration, deform | transforms. It is also possible to control the density and thickness of the treated non-woven fibers by adjusting the distance between the belts.

  In order to supply water vapor to the fiber web, a conventional water vapor jet apparatus is used. As this steam spraying device, a device capable of spraying steam substantially uniformly over the entire width of the web at a desired pressure and amount is preferable. When two belt conveyors are combined, water vapor is supplied to the web through a water-permeable conveyor belt or a conveyor net placed on the conveyor. A suction box may be attached to the other conveyor. Excess water vapor that has passed through the fiber web can be sucked and discharged by the suction box. Further, in order to perform steam treatment on both sides of the front and back of the fiber web at a time, in a conveyor opposite to the conveyor on which the steam spraying device is mounted, more than the portion on which the steam spraying device is mounted. You may install another water vapor | steam injection apparatus in the conveyor of a downstream part. If there is no downstream steam injection device and suction box, if you want to steam-treat the front and back of the fiber web, you can substitute the front and back of the fiber web that has been treated once and pass through the treatment device again Good.

  The endless belt used for the conveyor is not particularly limited as long as it does not hinder the conveyance of the fiber web or the high-temperature steam treatment. However, when high-temperature steam treatment is performed, the surface shape of the belt may be transferred to the surface of the fiber web depending on the conditions. In particular, when it is desired to obtain a fiber assembly having a flat surface, a net having a fine mesh may be used. The upper limit is about 90 mesh, and a net that is roughly coarser than 90 mesh (for example, a net of about 10 to 50 mesh) is preferable. A finer mesh net than this has low air permeability and makes it difficult for water vapor 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 resin, etc. The heat resistant resin is preferable.

  Since the high-temperature steam sprayed from the steam spraying device is an air stream, unlike the hydroentanglement process or the needle punch process, the fibers in the fiber web that is the object to be processed enter the inside of the fiber web without largely moving. . It is considered that due to the invasion action and wet heat action of the water vapor flow into the fiber web, the water vapor flow efficiently covers the surface of each fiber existing in the fiber web in a wet heat state, and uniform heat bonding becomes possible. In addition, since the heat can be sufficiently conducted to the inside of the fiber as compared with the dry heat treatment, the degree of crimp in the surface and the thickness direction becomes substantially uniform.

  The nozzle for injecting the high-temperature steam may be a plate or a die in which predetermined orifices are continuously arranged in the width direction, and may be arranged so that the orifices are arranged in the width direction of the fiber 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.

  When using a type of nozzle having an orifice in the plate, the thickness of the plate may be about 0.5 to 1 mm. The diameter and pitch of the orifice are not particularly limited as long as the target fiber fixation and crimp expression can be efficiently realized, but the diameter of the orifice is usually 0.05 to 2 mm, preferably 0. It is about 1-1 mm, More preferably, it is about 0.2-0.5 mm. The pitch of the orifices is usually about 0.5 to 3 mm, preferably about 1 to 2.5 mm, and more preferably about 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, it will be difficult to obtain a sufficient water vapor injection force. On the other hand, if the pitch is too small, the nozzle holes become too dense and the strength of the nozzle itself is reduced. On the other hand, if the pitch is too large, there are cases where high-temperature water vapor does not sufficiently hit the fiber web, making it difficult to ensure web strength.

  The high-temperature steam to be used is not particularly limited as long as the target fiber can be fixed, and may be set depending on the material and form of the fiber to be used. The pressure is, for example, 0.1 to 2 MPa, preferably 0. The pressure is about 2 to 1.5 MPa, more preferably about 0.3 to 1 MPa. If the water vapor pressure is too high or too strong, the fibers forming the web will move more than necessary, causing turbulence, or the fibers will melt too much to partially retain the fiber shape, There is a possibility of bonding more than necessary. Also, if the pressure is too weak, the amount of heat necessary for fiber fusion and crimp development cannot be given to the web being processed, or water vapor cannot penetrate the web, causing fiber fusion spots in the thickness direction. And crimps may become uneven. In addition, it may be difficult to control the uniform ejection of water vapor from the nozzle.

  The temperature of the high-temperature steam is, for example, about 100 to 150 ° C, preferably about 100 to 120 ° C, and more preferably about 100 to 110 ° C. The processing speed of the high temperature steam is, for example, 200 m / min or less, preferably 0.1 to 100 m / min, and more preferably about 1 to 50 m / min.

  If necessary, a plurality of plate-like fiber assemblies may be stacked to form a stacked body, or may be stacked with other materials to form a stacked body.

  Further, as described above, the step of entanglement of the nonwoven fiber aggregate web is obtained by adhering wet heat-adhesive fibers with high-temperature steam, but other conventional methods, for example, processing methods such as needle punching It may be adhered by.

  The nonwoven fiber assembly obtained by such a method is usually formed into a sheet shape or a plate shape. The sheet-like nonwoven fiber aggregate is formed into the nonwoven fiber aggregate of the present invention by crushing, pulverizing, or cutting so as to have the above-mentioned size. As long as the desired volume can be obtained, the method for forming the nonwoven fiber assembly is not particularly limited, and a conventional machine such as a single-screw crusher, a biaxial crusher, or a high-speed cutter may be used. Furthermore, in the present invention, the non-woven fiber aggregate is a waste material, for example, a piece generated in a cutting or crushing process in the production process of the present invention, a waste or a used non-woven fiber aggregate (for example, a board shape). An aggregate obtained by pulverizing or cutting non-woven fiber aggregates used in the form or the like, or non-woven fiber molded bodies of the present invention) may also be used. In this invention, since such a waste material can be utilized, it is excellent also in recyclability.

(Thermal bonding process of non-woven fiber assembly)
In the thermal bonding step, the method of thermally bonding a plurality of nonwoven fiber aggregate units is not particularly limited, and may be a method of heating using hot air or hot water, but the nonwoven fiber aggregate molding step Similarly to the above, a method of heat bonding using high temperature steam is preferable. When high-temperature steam is used, the above-mentioned waste material can be satisfactorily heat-bonded as a non-woven fiber aggregate. For example, even when heat-bonding treatment is repeated a plurality of times (for example, 5 times or more), Since the woven fiber assembly can be thermally bonded well, it can be reused repeatedly.

  Examples of the method of bonding the nonwoven fiber aggregates and forming them into a board shape include a steam treatment method while uniformly dispersing the nonwoven fiber aggregates on the conveyor.

  In order to form a complicated three-dimensional structure, a steam press molding machine can be used. The steam press molding machine is not particularly limited, but may be a molding machine in which the lower mold has a concave shape and can be filled with a non-woven fiber assembly from the viewpoint of productivity. For supplying steam, a steam supply hole may be provided in the mold. FIG. 4 is a schematic view showing an example of a steam press molding machine. The steam press molding machine 30 includes an upper mold 31, and a lower mold 33 that can be fitted into the upper mold 31 and has a gap 32 that can be filled with a non-woven fiber assembly. The bottom mold 32 has a steam supply hole 34 for supplying high-temperature steam. The steam press molding machine is not limited to such a steam press molding machine, and the upper mold may be opened and steam may be supplied from the gap. The diameter and pitch of the steam supply holes opened in the mold are not particularly limited as long as the block-like nonwoven fiber aggregates can be sufficiently bonded to each other, but are usually 0.1 to 3 mm, preferably about 0.5 to 2 mm. is there. If the steam supply hole 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, it will be difficult to obtain a sufficient water vapor injection force.

The filling amount of the nonwoven fiber aggregate to be filled into the steam press molding machine is not particularly limited, but by adjusting the filling amount, the apparent density of the molded article is set to 0. 0 regardless of the apparent density of the nonwoven fiber aggregate. It can be adjusted to 01 to 0.7 g / cm ³ . In the present invention, when orienting a nonwoven fiber assembly in a random direction, a predetermined amount of the nonwoven fiber assembly is filled into a steam press molding machine (especially a steam press molding machine having a lower mold having a void). Therefore, it is possible to produce a molded body simply by heat bonding. Furthermore, by changing the shape of the mold, a three-dimensional shaped product having a complicated three-dimensional structure can be easily formed.

  The steam used is not particularly limited as long as the non-woven fiber aggregates can be sufficiently bonded to each other, and the pressure is, for example, about 0.05 to 2 MPa, preferably about 0.07 to 1.5 MPa. If the steam pressure is too high or too strong, the non-woven fiber assembly will move more than necessary to form a non-uniform adhesive structure, or the area around the steam supply hole will adhere more than necessary, resulting in higher density. there is a possibility. On the other hand, if the pressure is too weak, it may not be possible to provide the amount of heat necessary for bonding the nonwoven fiber assembly, and the density may be uneven. In addition, it may be difficult to control the uniform ejection of steam from the steam supply hole.

  A steam fan may be attached to the steam press molding machine, and the steam staying in the mold may be sucked from the steam ejection hole and cooled. By cooling, the time during which the wet heat adhesion is fixed can be shortened.

  As a heat retention temperature of a metal mold | die, 100-120 degreeC is desirable. When the mold temperature is less than 100 ° C., vapor condenses on the mold surface and causes uneven adhesion. If the temperature exceeds 120 ° C., an excessive heat history is imparted to the wet heat-adhesive fiber, so that remolding cannot be performed.

  It is also possible to obtain a molded body by the above-mentioned method after mixing the constituent units of other materials into the nonwoven fiber assembly.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Each physical property value in the examples was measured by the following method. In the examples, “parts” and “%” are based on mass unless otherwise specified.

(1) Weight per unit area (g / m ² )
Measured according to JIS L1913 “Testing method for general short fiber nonwoven fabric”.

(2) Thickness (mm), apparent density (g / cm ³ )
The thickness was measured according to JIS L1913 “Test method for general short fiber nonwoven fabric”, and the apparent density was calculated from this value and the basis weight value.

(3) Number of crimps Evaluation was made according to JIS L1015 “Testing method for chemical fiber staples” (8.12.1).

(4) Thermal conductivity It measured by the unsteady hot wire method according to "JIS R2648, the test method of the heat conductivity by the hot wire method of a refractory heat insulation brick".

(5) Air permeability Measured by fragile method according to JIS L1096.

(6) Formability 20 g of non-woven fiber assembly having a size of 1 cm ³ is filled into a steam press molding machine having a mold (width 22 cm, depth 30 cm, height 10 mm) having the shape shown in FIG. 4, and a density of 0.03 g / cm. ^{3. It} shape | molded into the molded object of thickness 10mm. The molded body was visually observed to see if it could hold the mold shape and evaluated according to the following criteria.

○: The shape of the mold is almost maintained, and the nonwoven fiber assemblies are adhered to each other. Δ: The shape of the mold is maintained, but some of the nonwoven fiber assemblies are dropped. : The shape of the mold cannot be maintained, and the nonwoven fabric aggregates are often dropped.

(7) Recyclability The molded body obtained in the moldability test was cut again by 1 cm ³ , and again using the steam press molding machine of FIG. 4, 0.07 MPa steam was applied for 30 seconds, and the density was 0.03 g / A regenerated product with cm ³ and a thickness of 10 mm was obtained. After repeating this five times, whether or not the molded body could hold the mold shape was visually observed and evaluated according to the following criteria.

○: The shape of the mold is almost maintained, and the nonwoven fiber assemblies are adhered to each other. Δ: The shape of the mold is maintained, but some of the nonwoven fiber assemblies are dropped. : The shape of the mold cannot be maintained, and the nonwoven fabric aggregates are often dropped.

(8) Bending toughness Measured according to Method A (3-point bending method) among the methods described in JIS K7017. At this time, the measurement sample was a 30 mm wide × 200 mm long sample, the distance between fulcrums was 50 mm, and the test speed was 2 mm / min. In addition, the measurement sample was extract | collected so that a web flow direction (MD) might become parallel. In the present invention, when the deflection is 30 mm, whether or not the sample is bent and broken is visually observed and evaluated according to the following criteria.

○: The sample form before the test is almost retained. ×: The sample form before the test is remarkably deformed.

(9) Sound absorption rate In accordance with “JISA1429 reverberation chamber method sound absorption rate measurement method”, the sound absorption rates at five frequencies of 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, and 5000 Hz were measured and evaluated according to the following criteria. In addition, in this evaluation, when there is no place where the sound absorption rate is 50% or more (0.5 or more), the reverberant sound becomes large, there is no sound absorption effect, and the place where the sound absorption rate is 50% or more is 1 to 3. In the case of the location, only the sound of a specific frequency is absorbed, resulting in an unnatural sound field and uncomfortable.

○: Sound absorption rate is 50% or more at all four or more frequencies. Δ: Sound absorption rate is 50% or more at 1 to 3 frequencies. ×: No sound absorption rate is 50% or more.

(10) Independence (morphological stability)
Whether or not the 120-cm (height) and cylindrical-shaped sound absorber having a diameter of 22 cm produced by the sound absorption coefficient test can stand by itself for 1 minute was confirmed by visual observation three times and evaluated according to the following criteria.

○: Independent without falling down three times. Δ: Independent without falling down once or twice. ×: Independent of one time.

Example 1
Core-sheath type composite staple fiber having a core component of polyethylene terephthalate and a sheath component of ethylene-vinyl alcohol copolymer (ethylene content 44 mol%, saponification degree 98.4 mol%) as wet heat adhesive fibers (Co., Ltd.) “Sophista”, fineness 3.3 dtex, fiber length 51 mm, core-sheath mass ratio = 50/50, number of crimps 21/25 mm, crimp ratio 13.5% was prepared.

A card web having a basis weight of about 500 g / m ² was prepared from the core-sheath type composite staple fiber (wet heat adhesive fiber) by a card method.

  The card web was transferred to a belt conveyor equipped with a 50 mesh, 500 mm wide stainless steel endless wire mesh. In addition, the belt conveyor which has the same metal mesh is equipped in the upper part of the metal mesh of this belt conveyor, and it rotated in the same direction at the same speed, respectively, and used the belt conveyor which can adjust the space | interval of these metal meshes arbitrarily. .

  Next, the steam web is introduced into the steam jetting device provided on the lower belt conveyor, and 0.2 MPa of high-temperature steam is jetted out (perpendicularly) in the thickness direction of the card web from this device. Steam treatment was performed to obtain a non-woven fiber assembly. In this steam spraying device, a nozzle is installed in the lower conveyor so as to spray high-temperature steam toward the web via a conveyor net, and a suction device is installed in the upper conveyor. Further, another jetting device, which is a combination of the arrangement of the nozzle and the suction device reversed, is installed on the downstream side in the web traveling direction of the jetting device, and steam treatment is performed on both the front and back sides of the web. did.

  In addition, the hole diameter of the water vapor | steam injection nozzle was 0.3 mm, and the water vapor | steam injection apparatus with which the nozzle was arranged in 1 row at 1 mm pitch along the width direction of the conveyor was used. The processing speed was 5 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.

Subsequently, a board having a thickness of 5 mm was cut with a high-speed cutter (width 1 cm × length 2 cm) to produce a 1 cm ³ nonwoven fiber assembly. The density of the nonwoven fiber assembly was 0.1 g / cm ³ , the air permeability was 51 cm ³ / (cm ² · sec), and the fiber adhesion rate was 31% on the front surface, 28% on the center, and 33% on the back surface. . Furthermore, a mold having a shape shown in FIG. 4 (width 22 cm, depth 30 cm, height 10 mm) was kept at 100 ° C., and 20 g of the above-mentioned nonwoven fiber assembly was filled in the recess. 0.07 MPa vapor was fed for 30 seconds to obtain a molded body having a density of 0.01 g / cm ³ and a thickness of 10 mm. The obtained molded article had good breathability, heat insulation, and durability. Furthermore, this molded body is cut again to 1 cm ³ , and filled in the mold again as a recycled material, given 0.07 MPa steam for 30 seconds, a recycled product having a density of 0.03 g / m ³ and a thickness of 10 mm. Obtained. The same regeneration was repeated 5 times, but the adhesion between the nonwoven fiber assemblies was good and the recyclability was good. The results are shown in Table 1.

Example 2
Except using a 170 degreeC hot stove, it carried out similarly to Example 1, and obtained the molded object which consists of a nonwoven fabric aggregate. The obtained molded article had good breathability, heat insulation, and durability. Further, a recycled product was obtained from this molded body in the same manner as in Example 1. The obtained recycled product retained the shape of the mold, but some of the non-woven fiber assemblies dropped off.

Comparative Example 1
A molded article comprising a non-woven fiber assembly in the same manner as in Example 1 except that a web having a basis weight of about 500 g / m ² obtained by a card method using polyethylene terephthalate fibers (fineness: 3 dtex, fiber length: 51 mm) was used. However, since the wet heat adhesive fibers were not included, an adhesive structure between the nonwoven fiber assemblies could not be formed and the form could not be maintained. The evaluation results are shown in Table 1.

Comparative Example 2
Table 1 shows the evaluation results of commercially available polystyrene foam (10 mm thick).

Comparative Example 3
Table 1 shows the evaluation results of commercially available polyurethane foam (Inoac, 10 mm thick).

表１の結果から明らかなように、実施例の成形体は、成形性、リサイクル性、曲げ靱性に優れている。

As is apparent from the results in Table 1, the molded articles of the examples are excellent in moldability, recyclability, and bending toughness.

Example 3
In the mold used in Example 1, the cut product of the non-woven fiber assembly obtained in the same manner as in Example 1 is a mold having a cylindrical recess (diameter of 22 cm in cross section, high diameter). 40 cm) was kept at 100 ° C., and 475 g of the above-mentioned nonwoven fiber assembly was filled in the recess. 0.07 MPa vapor was fed for 30 seconds to obtain a molded body having a density of 0.03 g / cm ³ , a circular cross section of 23 cm in diameter, and a height of 40 cm. Three of these molded bodies were produced and stacked so as to form a cylinder having a height of 120 cm to produce a 1.4 kg sound absorber. The obtained molded body was excellent in sound absorption, lightweight, and self-supporting. In addition, the graph of the sound absorption rate in each frequency is shown in FIG.

Comparative Example 4
A board having a thickness of 10 mm was obtained in the same manner as in Example 1 except that the distance (distance) between the upper and lower conveyor belts on the nozzle side and the suction side was 10 mm. Next, the obtained board having a thickness of 10 mm was punched out using a die having a diameter of 22 cm to obtain a disk-shaped molded body (diameter: 22 cm, thickness: 10 mm) having a density of 0.05 g / cm ³ . 120 compacts were stacked to produce a 2.3 kg sound absorber. The obtained molded article was excellent in sound absorption and lightweight, but it was difficult to make it independent. In addition, the graph of the sound absorption rate in each frequency is shown in FIG.

Comparative Example 5
A commercially available 12k glass wool roll (density 0.012 g / cm ³ , thickness 100 mm, 1200 mm width) was cut to 95 cm. The cut product was wound in a roll shape (pile-like shape) to create a sound absorber having a diameter of 22 cm, a height of 120 cm, and a weight of 1.4 kg.

  The evaluation results of Example 3 and Comparative Examples 4 to 5 are shown in Table 2.

表２の結果から明らかなように、実施例３の成形体は、吸音性に優れているともに、自立性も高い。これに対して、比較例では、自立性が低い。特に、比較例４では、自立性が低い上に、厚みの大きい三次元成形体の製造も困難である。

As is apparent from the results in Table 2, the molded product of Example 3 is excellent in sound absorption and has high self-supporting properties. In contrast, the comparative example has low independence. In particular, in Comparative Example 4, it is difficult to produce a three-dimensional molded product having a low thickness and a large thickness.

  The nonwoven fiber molded body of the present invention is lightweight and bulky and has excellent breathability, heat insulation, durability, moldability, and recyclability, so that it has a sound absorbing material, heat insulation material, flooring material, air conditioning filter, and It can be used as a drainage filter, a transpiration plate, a rooftop greening base material, a microorganism carrier for water purification, a wiping material, a water absorbing material and the like. In addition, because of its excellent cushioning properties, it can be used as a food / fruit packing material, or as a cushioning material in various fields (industrial, agricultural, daily life, etc.), such as sofas, beds, pillows, vehicle cushions, helmets, insoles, rugs, etc. . In addition, it is lightweight and sound-absorbing, and has excellent form stability, so buildings (eg, houses, factory houses and facilities, buildings, hospitals, schools, gymnasiums, cultural halls, public halls, highway soundproof walls, etc.) ) And vehicles (for example, vehicles such as automobiles, airplanes, etc.) can be used effectively.

DESCRIPTION OF SYMBOLS 1,11,21 ... Nonwoven fiber molded object 2,3,12,22 ... Nonwoven fiber assembly 30 ... Steam press molding machine 31 ... Upper metal mold 32 ... Gap part 33 ... Lower metal mold 34 ... Steam supply hole

Claims (13)

Formed of a plurality of non-woven fiber assembly, and apparent density of a nonwoven fiber molded body is 0.01 to 0.05 g / cm ^3, the nonwoven fiber assembly comprises a thermal adhesive fiber under moisture, The fibers are fixed by fusion of the wet heat adhesive fibers, the ratio of the number of wet heat adhesive fibers on the surface of the nonwoven fiber aggregate is 70% or more, and the nonwoven fiber aggregates are bonded to each other by the wet heat adhesive. A non-woven fiber molded article fixed by fusion of a conductive fiber. Nonwoven fiber aggregate is indeterminate shape, and the number ratio of the thermal adhesive fiber under moisture in the surface of the nonwoven fiber assembly is 90% or more claims 1 Symbol placement molded body. The molded body according to claim 1 or 2 , wherein the nonwoven fiber aggregate is anisotropic and each nonwoven fiber aggregate is oriented in a random direction. Nonwoven fiber assembly, claim 1-3 is a waste of wet heat adhesive nonwoven fiber aggregate fibers are fixed by fusion of fibers or molded product obtained from the non-woven fiber assembly The molded product according to 1. The molded body according to any one of claims 1 to 4 , wherein the volume of the nonwoven fiber assembly is 0.01 to 300 cm ³ . The apparent density is 0.01 to 0.032 g / cm ³ , the air permeability by the Frazier method is 0.1 to 300 cm ³ / (cm ² · sec), and the thermal conductivity is 0.03 to 0 It is 1 W / m * K , The molded object in any one of Claims 1-5 . The non-woven fiber assembly further includes non-wet heat adhesive fibers, and the ratio (mass ratio) between the wet heat adhesive fibers and the non-wet heat bond fibers is wet heat bond fibers / non-humid heat bond fibers = 10/90 to 99. The molded article according to any one of claims 1 to 6 , which is / 1. The wet heat adhesive fiber is formed of an ethylene-vinyl alcohol copolymer having an ethylene unit content of 10 to 60 mol% and a non-wet heat adhesive resin, and the ethylene-vinyl alcohol copolymer and the non-wet heat adhesive resin. The former / the latter = 90/10 to 10/90, and the ethylene-vinyl alcohol copolymer continues at least part of the wet heat adhesive fiber surface in the length direction. The molded body according to any one of claims 1 to 7 . The molded body according to any one of claims 1 to 8, wherein the non-woven fiber aggregate is formed of wet heat adhesive fibers alone. Humid heat-adhesive fiber is a sheath composed of a wet heat-adhesive resin and a core composed of at least one non-humid heat-adhesive resin selected from the group consisting of polypropylene resin, polyester resin and polyamide resin The molded body according to any one of claims 1 to 9 , which is a core-sheath composite fiber formed with a part. The molded body according to any one of claims 1 to 10 , wherein the nonwoven fiber assemblies are thermally bonded using high-temperature steam.   The manufacturing method of the molded object of Claim 1 including the process of heat-bonding several nonwoven fiber aggregates. The manufacturing method of the molded object of Claim 12 heat-bonded with high temperature steam.

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