JP2009242995A - Platy formed article and use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a platy formed article having light weight, low density, high strength, and excellent biodegradability, and to provide use of the formed article. <P>SOLUTION: The platy formed article contains a fiber containing a biodegradable polymer at least on the surface and having a nonwoven fiber structure, provided that the fibers are welded and integrated at a welding ratio of 5-85% by the fusion of the biodegradable polymer and the formed article has an apparent density of 0.05-0.7 g/cm<SP>3</SP>. Also provided is a board for building use composed of the platy formed article. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plate-like molded body that is lightweight, high in strength, and excellent in biodegradability.

  Conventionally, the plate-shaped molded object comprised with the biodegradable material is used for a wide use. In particular, a plate-like molded body having a non-woven fiber structure has the original strength and breathability of fibers, and is widely used in applications such as building materials.

Examples of these plate-like molded products include plates made of natural wood. Due to the depletion of natural resources, a lot of plant fibers or a plywood made by bonding a plant fiber sheet to another material with an organic adhesive or the like is used. For example, a fiber board having a density of 600 to 900 kg / m ^3, which is obtained by bonding kenaf fibers obtained by defibrating a mallow plant and kenaf with a thermosetting adhesive, is known (Patent Document 1). ). These suffer from health problems due to volatilization of the remaining organic adhesive. In addition, in order to improve the strength and designability of the plywood, resin may be impregnated or coated, but these are not only low in productivity, but also have high specific gravity and impair the original breathability of the plate-like molded product It will be.

  As a fiber bonding method, it is also possible to use a hot press treatment in which fibers having a relatively low softening temperature are made into a plate shape and the main surface is compression-molded with a high heat molding plate. In this case, the fibers near the surface of the molded body are preferentially adhered, and the internal fibers are not sufficiently adhered. Therefore, when expressed in extreme terms, it becomes a cushion-like structure with a hard skin on the surface. It becomes a plate-like molded product having a low hardness for a high air permeability and low air permeability. The thicker (for example, 5 mm or more) plate-shaped molded article suitable for many uses increases this tendency, so the practicality is lowered. Even if the strength is ensured by applying a high pressing pressure, the density is high and the air permeability is low.

Japanese Patent Laid-Open No. 2004-314592

  Accordingly, an object of the present invention is to provide a plate-like molded body that is lightweight and has a low density, high strength, and excellent biodegradability. Moreover, the other objective of this invention is to provide the use which uses these plate-shaped molded objects.

The plate-shaped molded article of the present invention according to claim 1 is a plate-shaped molded article that includes a fiber having a biodegradable polymer at least on its surface and has a non-woven fiber structure, wherein the biodegradable polymer is melted. It is a plate-like molded body having an apparent density of 0.05 to 0.7 g / cm ³ which is bonded and integrated with a fiber adhesion rate of 5 to 85% by wearing.

  The plate-like molded product of the present invention according to claim 2 has a fiber adhesion rate of 85% or less in each region divided into three equal parts in the thickness direction in the cross section in the thickness direction, and in each region. The plate-shaped molded product according to claim 1, wherein the difference between the maximum value and the minimum value of the fiber adhesion rate is 20% or less.

  The plate-like molded product of the present invention according to claim 3 has a fiber filling rate of 20 to 80% in each region divided into three equal parts in the thickness direction in the cross section in the thickness direction, and each region. The plate-shaped molded article according to claim 1 or 2, wherein the difference between the maximum value and the minimum value of the fiber filling rate in the sheet is 20% or less.

  The plate-shaped molded product of the present invention according to claim 4 is characterized in that the weight ratio of the biodegradable polymer to the whole is 10% or more, and the plate according to any one of claims 1 to 3 It is a shaped molded body.

  The plate-shaped molded product of the present invention according to claim 5 contains fibers in which the biodegradable polymer is a single polymer component, and the plate according to any one of claims 1 to 4 It is a shaped molded body.

  The plate-shaped molded article of the present invention according to claim 6 is composed of two or more kinds of polymer components, each containing a composite fiber that is a biodegradable polymer. It is a plate-shaped molded object of any 1 item | term.

  The plate-shaped molded article of the present invention according to claim 7 is a composite fiber comprising two or more polymer components, containing at least one biodegradable polymer, and the remaining components being a thermoplastic polymer. It is a plate-shaped molded object of any one of Claims 1-6 characterized by the above-mentioned.

  The plate-shaped molded product according to claim 8 is the plate-shaped molded product according to any one of claims 1 to 7, wherein the biodegradable polymer is polylactic acid.

  The plate-shaped molded product according to any one of claims 1 to 8, wherein the plate-shaped molded product according to the present invention includes at least one selected from the group consisting of a boron-based flame retardant and a silicon-based flame retardant. Is the body.

  The plate-shaped molded product of the present invention according to claim 10 is a plate-shaped molded product according to any one of claims 1 to 9, which is a heat-insulating and / or air-permeable plate-shaped molded product.

  The building material board according to claim 11 is a building material board constituted by the plate-like molded body according to any one of claims 1 to 10.

  In the present invention, since the plate-shaped molded body is integrated by fusion of the biodegradable polymer, it is quickly collapsed and reduced in volume by degrading the biodegradable polymer, so that it can be easily compacted in a short time when discarded. It is packed and easy to carry. In addition, it is easy to decompose in nature after disposal, and the load on the environment is low. Moreover, since the fiber adhesion rate is in an appropriate range, it has strength and hardness suitable for applications such as building materials. Moreover, since it is integrated by the non-woven fiber structure, it is flexible and suitable for applications requiring earthquake resistance. Further, since they are integrated by fusion of fibers, they can be re-formed by heat treatment. For example, an embossed pattern can be formed on the surface, or a curved surface can be formed. Furthermore, this plate-like molded body can be composed essentially of fibers, and it is not necessary to add chemical binders or special chemicals, so use components that generate harmful components (such as volatile organic compounds such as formaldehyde). And can be easily manufactured. Furthermore, this plate-like molded body is low-density and lightweight, and can realize high air permeability, heat insulation, and sound absorption by a synergistic effect with the non-woven fiber structure. Therefore, the building material board of the present invention can have the preferable characteristics as described above.

  The plate-like molded body of the present invention has the lightness and breathability that cannot be obtained with a normal nonwoven fabric by simultaneously arranging the arrangement of fibers constituting the nonwoven fiber structure and the bonding state between the fibers within a predetermined range. It can be secured.

  In addition, the biodegradable polymer contained in the plate-shaped molded body is a wet heat adhesive resin, so that high temperature (overheated or heated) water vapor acts on the web, and the adhesive action is exhibited at a temperature below the melting point of the wet heat adhesive resin. In addition, the fibers can be obtained by partially bonding and converging the fibers. That is, it is obtained by point-bonding or partial-bonding single fibers and bundle fibers so as to form a so-called “scrum” while maintaining moderately small voids under wet heat. Due to the high permeability of high-temperature steam and the amount of heat, the web is fused uniformly at high speed, so that the fiber adhesion rate is uniform not only in the surface direction but also in the thickness direction, so that the strength and hardness are high.

The heat-adhesive resin only needs to be capable of expressing an adhesive function by flowing or easily deforming at a temperature and humidity that can be easily realized by high-temperature steam. Specifically, a thermoplastic resin that can be softened with hot water (for example, about 80 to 150 ° C., particularly about 95 to 100 ° C.) and can be self-adhered or bonded to other fibers, such as a cellulose resin (C _1-3). Alkyl cellulose ether, hydroxy C _1-3 alkyl cellulose ether, carboxy C _1-3 alkyl cellulose ether or a salt thereof), polyalkylene glycol resin (poly C _2-4 alkylene oxide such as polyethylene oxide and polypropylene oxide), polyvinyl Resin (polyvinyl pyrrolidone, polyvinyl ether, vinyl alcohol polymer (ethylene-vinyl alcohol copolymer, etc.), polyvinyl acetal, etc.), acrylic copolymer and its alkali metal salt, modified vinyl copolymer, hydrophilic Introducing the replacement machine And polymers (polyesters, polyamides, polystyrenes or salts thereof introduced with sulfonic acid groups, carboxyl groups, hydroxyl groups, etc.), aliphatic polyester resins and the like. Further, among the polyolefin-based resins, polyester-based resins, polyamide-based resins, polyurethane-based resins, thermoplastic elastomers, and the like, resins that can be softened at a temperature of hot water (high-temperature steam) to develop an adhesive function are also included. These resins can be used alone or in combination of two or more. Of these, biodegradable polymers having biodegradability are desirable in the configuration of the present invention.

  Examples of the biodegradable polymer include poly (α-hydroxy acid) such as polyglycolic acid and polylactic acid, and copolymers having these as main repeating unit elements. Further, poly (ω-hydroxyalkanoate) such as poly (ε-caprolactone) and poly (β-propiolactone) is further added to poly-3-hydroxypropionate, poly-3-hydroxybutyrate, poly Poly (β-hydroxyalkanoates) such as -3-hydroxycaprolate, poly-3-heptanoate, poly-3-hydroxyoctanoate, and repeating unit elements constituting them and poly-3-hydroxyvalerate Examples thereof include copolymers with repeating unit elements constituting poly-4-hydroxybutyrate. Examples of polyalkylene dicarboxylates composed of a condensate of glycol and dicarboxylic acid include polyethylene oxalate, polyethylene succinate, polyethylene adipate, polyethylene azelate, polybutylene oxalate, polybutylene succinate, polybutylene adipate, poly Examples include butylene sebacate, polyhexamethylene sebacate, polyneopentyl oxalate, or polyalkylene dicarboxylate copolymer having these as repeating unit elements. In the present invention, a plurality of polymers can be selected from these aliphatic polyesters and mixed for use. It is most desirable that the plate-like molded body of the present invention is integrated substantially only by fusion of the biodegradable polymer, but it does not deny the use of another meltable polymer. For example, another meltable polymer may be used as long as it is not mainly involved in melt bonding. For example, another meltable polymer may be used for the core portion of the core-sheath composite fiber, and the melt temperature is higher than that of the biodegradable polymer (for example, 20 ° C or higher, preferably 30 ° C or higher, more preferably 40 ° C or higher). ) May be integrated so that the biodegradable polymer is mainly melted, and even if melted, the adhesion rate and the fiber surface coverage are sufficiently lower than the biodegradable polymer (for example, biodegradable) The ratio of the fiber surface coverage ratio between the polymer and another meltable polymer may be 60:40 or more, preferably 70:30 or more, and more preferably 80:20 or more.

  In the invention, from the viewpoints of yarn production and degradability in soil or compost, among the above-mentioned polylactic acid polymers, polybutylene succinate, polyethylene succinate, polybutylene adipate, polybutylene sebacate. Any one of the polymers, a copolymer having these polymers as a repeating unit, and a blend of these polymers are particularly suitable.

  Most preferably, the biodegradable polymer is a polylactic acid polymer, specifically, poly (D-lactic acid), poly (L-lactic acid), and a copolymer of D-lactic acid and L-lactic acid. Of these, a polymer having a melting point of 80 ° C. or higher is preferable among the copolymer of D-lactic acid and hydroxycarboxylic acid or the copolymer of L-lactic acid and hydroxycarboxylic acid. Here, as the hydroxycarboxylic acid in the case of a copolymer of lactic acid and hydroxycarboxylic acid, glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid, hydroxyheptanoic acid, hydroxyoctanoic acid, etc. Can be mentioned.

  The polylactic acid in the present invention preferably has a number average molecular weight of about 20,000 or more, preferably 40,000 or more, and more preferably 60,000 or more from the viewpoint of yarn forming properties and strength properties of the obtained yarn.

  The cross-sectional shape of the biodegradable fiber (cross-sectional shape perpendicular to the length direction of the fiber) is a general solid cross-sectional shape such as a round cross-section or an irregular cross-section (flat, elliptical, polygonal, 3 -14 leaf shape, T-shape, H-shape, V-shape, dogbone (I-shape, etc.), etc., and may be a hollow cross-section. The biodegradable fiber may be a composite fiber composed of at least a biodegradable resin.

  Examples of the cross-sectional structure of the composite fiber include a core-sheath type, a sea-island type, a side-by-side type, a multi-layer bonding type, a radial bonding type, and a random composite type.

  In the case of a composite fiber, two or more kinds of biodegradable polymers may be combined, or may be combined with a thermoplastic polymer that does not have biodegradability.

Examples of the thermoplastic polymer include cellulose resins (C _1-3 alkyl cellulose ether, hydroxy C _1-3 alkyl cellulose ether, carboxy C _1-3 alkyl cellulose ether, or salts thereof), and polyalkylene glycol resins. (Polyethylene oxide, polypropylene oxide, etc.), polyvinyl resins (polyvinyl pyrrolidone, polyvinyl ether, vinyl alcohol polymers (ethylene-vinyl alcohol copolymer, etc.), polyvinyl acetals, etc.), acrylic copolymers and alkali metal salts thereof , Modified vinyl copolymer, polyolefin resin, (meth) acrylic resin, vinyl chloride resin, styrene resin, polyester resin, polyamide resin, polycarbonate resin, polyurethane Resins, and thermoplastic elastomers. These resins can be used alone or in combination of two or more.

  As a polyester-type resin, the structural unit induced | guided | derived from a bifunctional compound as an acid unit and a glycol unit may contain the 1 type (s) or 2 or more types as a copolymer unit as needed. Such structural units derived from other bifunctional compounds include terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid and the like. Aromatic dicarboxylic acids; Aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid and dodecanedioic acid; alicyclic dicarboxylic acids such as decalin dicarboxylic acid and cyclohexanedicarboxylic acid; glycolic acid , Hydroxy carboxylic acids such as hydroxybenzoic acid, mandelic acid, matrolactic acid; aliphatic lactones such as ε-caprolactone; ethylene glycol, trimethylene glycol, tetramethylene glycol, 1,5-pentanediol , 1,6-hexanediol, neopentyl glycol, diethylene glycol, polyethylene glycol, polybutylene glycol and other aliphatic diols; hydroquinone, catechol, naphthalenediol, resorcin, 1,4-bis (β-oxyethoxy) benzene and other fragrances Diols; structural units derived from bifunctional components such as cycloaliphatic diols such as cyclohexanedimethanol. By making the biodegradable polymer polyester-based, the entire polymer constituting the plate-shaped molded product can be made polyester-based, so it has excellent air quality and less interfacial peeling, and has excellent strength and biodegradation treatment Is also easier.

  Polyamide resins are synthesized from aliphatic polyamides such as polyamide 6, polyamide 66, polyamide 6-10, polyamide 10, polyamide 12, and polyamide 6-12, and their copolymers, directional dicarboxylic acids and aliphatic diamines. Semi-aromatic polyamides are preferred. These polyamide-based resins may also contain other copolymerizable units.

  In the case of a composite fiber of biodegradable polymers or a composite fiber of a biodegradable polymer and a thermoplastic polymer, the weight ratio of the two types of polymers can be selected according to the structure (for example, core-sheath structure), 90 / 10 to 10/90, preferably about 80/20 to 20/80. If the proportion of one resin is too small, it may become unsatisfactory during spinning.

  The average fineness of the fibers forming the nonwoven fiber structure can be selected from the range of, for example, about 0.01 to 100 dtex, preferably about 0.1 to 50 dtex, more preferably about 0.5 to 30 dtex, depending on the application. . When the average fineness is within this range, the card has good passability when the plate-shaped molded body is formed.

  The average fiber length of the fibers forming the non-woven fiber structure can be selected from the range of, for example, about 10 to 150 mm, preferably about 20 to 100 mm, and more preferably about 25 to 80 mm. When the average fiber length is within this range, the fibers are sufficiently entangled, so that the mechanical strength of the plate-like molded body is improved.

  The crimp rate of the fibers forming the nonwoven fiber structure is, for example, about 1 to 50%, preferably 3 to 40%, and more preferably about 5 to 30%. The number of crimps is, for example, about 1 to 100 pieces / inch, preferably about 5 to 50 pieces / inch, and more preferably about 10 to 30 pieces / inch.

The plate-like molded product of the present invention may further contain fibers made of a thermoplastic polymer having no biodegradability. Examples of the fibers include polyester fibers (polyethylene terephthalate fibers, polytrimethylene terephthalate fibers, polybutylene terephthalate fibers, polyethylene naphthalate fibers, and the like), polyamide fibers (polyamide 6, polyamide 66, polyamide 11, Polyamide 12, Polyamide 6-10, Polyamide 6-12 and other aliphatic polyamide fibers, Semi-aromatic polyamide fibers, Polyphenylene isophthalamide, Polyhexamethylene terephthalamide, Poly p-phenylene terephthalamide and other aromatic polyamide fibers Fibers), polyolefin fibers (poly _C2-4 olefin fibers such as polyethylene and polypropylene), acrylic fibers (acrylonitrile-vinyl chloride copolymer, etc.) Acrylonitrile fibers having rilonitrile units), polyvinyl fibers (polyvinyl acetal fibers, etc.), polyvinyl chloride fibers (polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-acrylonitrile copolymer fibers, etc.) ), Polyvinylidene chloride fiber, polyparaphenylene benzobisoxazole fiber, polyphenylene sulfide fiber, cellulose fiber (for example, rayon fiber, acetate fiber, etc.). These fibers can be used alone or in combination of two or more.

  In addition to fibers containing biodegradable polymers and non-biodegradable thermoplastic polymers, natural fibers (cotton, wool, silk, hemp, etc.), semi-synthetic fibers (triacetate fibers, etc.) Acetate fiber, etc.) and recycled fiber (rayon, polynosic, cupra, lyocell, etc.).

  The weight ratio of the fibers having at least the surface of the biodegradable polymer in the plate-shaped molded body is preferably 50% or more. Preferably it is 60% or more. This is the same when it is composed only of fibers containing biodegradable polymers or when it is composed of a mixture of fibers containing biodegradable polymers and non-biodegradable fibers. .

  The plate-like molded product (or fiber) of the present invention further contains conventional additives such as stabilizers (heat stabilizers such as copper compounds, ultraviolet absorbers, light stabilizers, antioxidants, etc.), fine particles, A colorant, an antistatic agent, a flame retardant, a plasticizer, a lubricant, a crystallization rate retarder, and the like may be contained. These additives can be used alone or in combination of two or more. These additives may be carried on the surface of the plate-shaped molded body or may be contained in the fiber.

  In addition, when the plate-like molded body (fiber) of the present invention is used for applications requiring flame retardancy such as automobile interior materials and aircraft inner wall materials described later, it is effective to add a flame retardant. It is. As the flame retardant, a conventional inorganic flame retardant or organic flame retardant can be used, and a halogen flame retardant or a phosphorus flame retardant which is widely used and has a high flame retardant effect may be used. There is a problem of acid rain accompanying the generation of halogen gas, and phosphorus-based flame retardants have a problem of eutrophication of lakes accompanying phosphorus compound runoff by hydrolysis. Therefore, in the present invention, as the flame retardant, it is preferable to use a boron-based flame retardant and / or a silicon-based flame retardant from the viewpoint of avoiding these problems and exhibiting high flame retardancy.

  Boron flame retardants include, for example, boric acid (orthoboric acid, metaboric acid, etc.), borate (eg, alkali metal borates such as sodium tetraborate, alkaline earth metal salts such as barium metaborate, boron Transition metal salts such as zinc acid) and condensed boric acid (salt). These boron-based flame retardants may be hydrated. These boron-based flame retardants can be used alone or in combination of two or more.

  Examples of the silicon-based flame retardant include silicone compounds such as polyorganosiloxane, oxides such as silica and colloidal silica, and metal silicates such as calcium silicate, aluminum silicate, magnesium silicate, and magnesium aluminosilicate. It is done.

  These flame retardants can be used alone or in combination of two or more. Of these flame retardants, a boron-based flame retardant such as boric acid or borax is preferred. In particular, it is preferable to combine boric acid and borax, and the weight ratio of the two is boric acid / borax = 90/10 to 10/90, preferably about 60/40 to 30/70. Boric acid and borax may be subjected to flame retardant processing as an aqueous solution. For example, 10 to 35 parts by weight of boric acid and 15 to 45 parts by weight of borax are added to 100 parts by weight of water and dissolved. May be adjusted to an aqueous solution.

  What is necessary is just to select the ratio of a flame retardant according to the use of a plate-shaped molded object, for example, 1 to 300 weight% with respect to the total weight of a plate-shaped molded object, Preferably 5-200 weight%, Furthermore, Preferably, it is about 10 to 150% by weight.

  The flame retarding method is the same as the conventional dip-nip processing, in which the plate-like molded product of the present invention is impregnated with or sprayed with an aqueous solution or emulsion containing a flame retardant, and is biaxial during fiber spinning. A method of extruding and spinning a resin kneaded with a flame retardant with an extruder or the like and using this fiber can be used.

(Characteristics of plate-shaped compacts)
The plate-shaped molded body of the present invention has a non-woven fiber structure obtained from the web composed of the fibers, and the shape thereof can be selected according to the use, but is a flat plate shape.

  Furthermore, in order to have a non-woven fiber structure having high surface hardness and bending hardness, and having a good balance between lightness and air permeability, the non-woven fiber web may be used. It is necessary that the arrangement state and the adhesion state of the fibers constituting the are appropriately adjusted. That is, it is preferable that the fibers constituting the fiber web are arranged so as to intersect each other while being arranged substantially parallel to the surface of the fiber web (non-woven fiber). Furthermore, it is preferable that the plate-shaped molded body of the present invention is fused at the intersection where the fibers intersect. In particular, a plate-like molded body that requires high hardness and strength is a bundle-like fused fiber that is fused in a bundle of several to several tens in a portion where fibers other than the intersection are arranged substantially in parallel. It may be formed. It seems that these fibers form a “scrum” by partially forming a fused structure at the intersection of single fibers, the intersection of bundle fibers, or the intersection of single fibers and bundle fibers. A structure (a structure in which fibers are bonded at an intersection and entangled like a mesh, or a structure in which fibers are bonded at an intersection to constrain adjacent fibers to each other) to achieve the desired bending behavior, surface hardness, etc. I can do it. In the present invention, it is desirable that such a structure is distributed substantially uniformly along the surface direction and the thickness direction of the fiber web.

  Here, “almost parallel to the fiber web surface” means a state in which a portion where a large number of fibers are locally arranged along the thickness direction is not repeatedly present. . More specifically, when an arbitrary cross section of the fiber web of the plate-shaped molded body is observed with a microscope, the existence ratio (number of fibers) continuously extending in the thickness direction over 30% of the thickness of the fiber web. The ratio) is 10% or less (particularly 5% or less) with respect to the total fibers in the cross section.

  The fiber is arranged in parallel to the fiber web surface because if there are many fibers arranged in the thickness direction (perpendicular to the web surface), the fiber arrangement may be disturbed in the periphery. This is because an unnecessarily large void is generated in the woven fiber, and the bending strength and surface hardness of the plate-like molded body are reduced. Therefore, it is preferable to reduce this gap as much as possible. For this purpose, it is desirable to arrange the fibers parallel to the fiber web surface.

  In addition, when the web is entangled by means such as a needle punch, it becomes easy to manufacture a high-density plate-shaped molded body. Further, when the fibers are entangled before fusing, the shape of the fibers is maintained before fusing, which facilitates the production of a plate-shaped molded article having a large thickness, which is advantageous in terms of production efficiency. However, strong fiber entanglement with a needle punch or the like is disadvantageous in that the fibers are arranged parallel to the fiber web surface. Further, since the density of the plate-shaped molded body is increased by the interlacing, it is difficult to manufacture a low-density and lightweight plate-shaped molded body. Therefore, from the viewpoint of arranging the fibers in parallel and light weight, it is preferable to reduce the degree of fiber entanglement or not to entangle. Thus, it can apply to various uses by selecting the necessity of needle punch processing and the strength of processing according to the use. For example, by adding a weak needle punch, it may be possible to obtain a low-density, high-strength plate-shaped molded body.

  In particular, when a load is applied in the thickness direction of the plate-shaped molded body of the present invention, if a large void portion exists, the void portion is crushed by the load and the surface of the plate-shaped molded body is easily deformed. Furthermore, when this load is applied to the entire surface of the plate-like molded body, the thickness tends to be reduced as a whole. Such a problem can be avoided if the plate-shaped molded body itself is made of a resin filling without voids, but this reduces the air permeability, and ensures that it is difficult to bend when bent (fold resistance) and lightweight. It becomes difficult.

  On the other hand, in order to reduce the deformation in the thickness direction due to the load, it is conceivable to make the fiber thinner and fill the fiber with higher density, but when trying to secure lightness and breathability with only thin fiber , The rigidity of each fiber is lowered, and the bending stress is reduced. In order to ensure bending stress, it is necessary to increase the fiber diameter to some extent. However, if thick fibers are simply mixed, it is easy to create a fairly large gap near the intersection of thick fibers, and the thickness direction It becomes easy to deform.

  Therefore, the plate-like molded body of the present invention is arranged such that the fibers are arranged in parallel along the surface direction of the web and dispersed (or the fiber direction is directed in a random direction), so that the fibers intersect each other, By adhering at the intersection, a small gap is created to ensure light weight. Furthermore, since such a fiber structure is continuous, an appropriate air permeability and surface hardness are secured. In particular, when a bundle of fibers fused in parallel in the fiber length direction is formed in a place where the fibers are aligned in parallel without intersecting with other fibers, compared to the case where the fibers are composed of only single fibers. High bending strength can be secured mainly. When a plate-like molded body with high hardness and strength is desired, several fibers are bonded at the intersection between the intersection points while the fibers are bonded at the intersection where the fibers are intersected. It is preferable to form a bundle of fibers. Such a structure can be confirmed from the existence state of the single fiber when the cross section of the plate-like molded body is observed.

  Furthermore, in the plate-shaped molded product of the present invention, the fiber constituting the nonwoven fiber structure is bonded to the biodegradable polymer by a fiber adhesion rate of 5 to 85%, preferably 10 to 70%, more preferably 20 to 60%. Bonded to the extent. Although the fiber adhesion rate in this invention can be measured by the method as described in the Example mentioned later, the ratio of the cross section number of the fiber which adhered 2 or more with respect to the cross section number of all the fibers in a non-woven fiber cross section is shown. Therefore, a low fiber adhesion rate means that a ratio of a plurality of fibers fused to each other (a ratio of fibers fused by fusing) is small.

  In the present invention, the fibers constituting the non-woven fiber structure are bonded at the contact points of the respective fibers. In order to express a large bending stress with as few contacts as possible, this bonding point is the thickness. It is preferable to distribute uniformly along the direction from the surface of the plate-shaped molded body to the inside (center) and the back surface. When the adhesion points are concentrated on the surface or inside, not only is it difficult to secure a sufficient bending stress, but also the shape stability in a portion where the adhesion points are small is lowered.

  Therefore, in the cross section in the thickness direction of the plate-shaped molded body, it is preferable that the fiber adhesion rate in each region divided in three in the thickness direction is in the above range. Furthermore, the difference between the maximum value and the minimum value of the fiber adhesion rate in each region is 20% or less (for example, 0.1 to 20%), preferably 15% or less (for example, 0.5 to 15%), and more preferably. Is 10% or less (for example, 1 to 10%). Furthermore, the ratio between the minimum value and the maximum value of the fiber adhesion rate in each region is preferably 70% or more, more preferably 80% or more, and still more preferably 85% or more. In the present invention, since the fiber adhesion rate has such uniformity in the thickness direction, the hardness, bending strength, folding resistance and toughness are further improved.

  In the present invention, the “region divided into three in the thickness direction” means each region divided into three equal parts by slicing in a direction perpendicular to the thickness direction of the plate-like molded body.

In the plate-shaped molded article of the present invention, the existence frequency of single fibers (single fiber end faces) in the cross section in the thickness direction is not particularly limited. For example, the existence frequency of single fibers existing in any 1 mm ^{2 of the} cross section is 100. The number of fibers / mm ² or more (for example, about 100 to 300) may be used, but when mechanical properties are required rather than light weight, the frequency of single fibers is, for example, 100 / mm ^2. Hereinafter, it may be preferably 60 pieces / mm ² or less (for example, 1 to 60 pieces / mm ² ), and more preferably 25 pieces / mm ² or less (for example, 3 to 25 pieces / mm ² ). If the frequency of single fibers is too high, the fusion of the fibers is small and the strength of the plate-like molded product is reduced. If the frequency of single fibers exceeds 100 / m ² , bundles of fibers are fused. Therefore, it becomes difficult to ensure high bending strength. Furthermore, in the case of a plate-shaped molded body, it is preferable that the fibers fused in a bundle shape are thin in the thickness direction of the plate-shaped molded body and have a wide shape in the surface direction (length direction or width direction).

In the present invention, the existence frequency of the single fiber is measured as follows. That is, a range corresponding to 1 mm ² selected from a scanning electron microscope (SEM) photograph of a cross section of the plate-like molded body is observed, and the number of single fiber cross sections is counted. Arbitrary several places are observed similarly from the photograph, and the average value per unit area of the single fiber end face is defined as the single fiber existence frequency. At this time, all the number of fibers in a single fiber state in the cross section are counted. That is, in addition to fibers that are completely in a single fiber state, even if a plurality of fibers are fused, a fiber that is separated from the fused portion in the cross section and is in a single fiber state is counted as a single fiber.

  The fiber having at least the surface of the biodegradable polymer in the plate-shaped molded body is not connected to the both ends in the thickness direction (by preventing the fiber from penetrating the plate-shaped molded body in the thickness direction), the fiber coming off, etc. It is possible to suppress the loss of the plate-like molded body due to the above. The manufacturing method for arranging the fibers in this way is not particularly limited, but a means for laminating a plurality of plate-like molded bodies and fusing them is simple and reliable. Moreover, the fiber which connects the both ends of the thickness direction of a plate-shaped molded object can be reduced significantly by adjusting the relationship between fiber length and the thickness of a plate-shaped molded object. From such points, the thickness of the plate-shaped molded body is 10% or more (for example, 10 to 1000%), preferably 40% or more (for example, 40 to 800%), more preferably, relative to the fiber length. 60% or more (for example, 60 to 700%), particularly 100% or more (for example, 100 to 600%). If the thickness of the plate-shaped product and the fiber length are in this range, the plate-shaped product will not lose its mechanical strength such as bending stress. it can.

  Thus, the density and mechanical properties of the plate-like molded body of the present invention are affected by the ratio and the presence state of the bundle-like fused fibers. The fiber adhesion rate indicating the degree of fusion can be easily measured based on the number of bonded fiber cross sections in a predetermined region by taking a photograph of an enlarged cross section of the plate-shaped molded body using SEM. However, when the fibers are fused in a bundle, each fiber is fused in a bundle or at an intersection, so that it is difficult to observe as a single fiber, especially when the density is high. easy. In this case, for example, the fiber having at least the biodegradable polymer of the plate-shaped molded article of the present invention is formed of a sheath part made of a biodegradable polymer and a core part made of a fiber-forming polymer. In the case where the core-sheath type composite fiber is bonded, the adhesion of the bonded portion is released by means such as melting and washing, and the fiber adhesion rate can be measured by comparing with the cut surface before the release. On the other hand, in the present invention, as an index reflecting the degree of fiber fusion, the ratio of the area occupied by the cross section formed by the fiber and the bundle of fiber bundles in the cross section of the plate-shaped molded body (cross section in the thickness direction) after molding, That is, a fiber filling ratio can also be used. The fiber filling rate in the cross section in the thickness direction is, for example, about 20 to 80%, preferably about 20 to 60%, and more preferably about 30 to 50%. When the fiber filling rate is too small, there are too many voids in the plate-shaped molded body, and it becomes difficult to secure desired surface hardness and bending stress. On the other hand, if it is too large, the surface hardness and bending stress can be sufficiently secured, but it becomes very heavy and the air permeability tends to decrease.

  The plate-like molded body including such a bundle-like fused fiber has a low presence frequency of the bundle-like fused fiber, in order to balance bending strength, surface hardness, lightness, and air permeability at a high level, and each It is preferable that the fibers (bundle fibers and / or single fibers) are bonded at a high frequency at the intersection. However, if the fiber adhesion rate is too high, the distances between the bonded points are too close to each other, the flexibility is lowered, and it becomes difficult to eliminate distortion due to external stress. For this reason, the plate-like molded body of the present invention needs to have a fiber adhesion rate of 85% or less. Since the fiber adhesion rate is not too high, a passage by a fine gap can be secured in the plate-shaped molded body, and lightness and air permeability can be improved. Therefore, in order to express a large bending stress, surface hardness and air permeability with as few contacts as possible, the fiber adhesion rate increases in the thickness direction from the surface of the plate-shaped molded body to the inside (center) and back. It is preferable to distribute uniformly along. If the adhesion points are concentrated on the surface or inside, it becomes difficult to ensure the air permeability in addition to the bending stress and the form stability described above.

  Therefore, in the plate-like molded body of the present invention, it is preferable that the fiber filling rate in each of the regions divided in three in the thickness direction is in the above range in the cross section in the thickness direction. Furthermore, the difference between the maximum value and the minimum value of the fiber filling rate in each region is 20% or less (for example, 0.1 to 20%), preferably 15% or less (for example, 0.5 to 15%), and more preferably. Is 10% or less (for example, 1 to 10%). In the present invention, if the fiber filling rate is uniform in the thickness direction, the bending strength, folding resistance, toughness and the like are excellent. The fiber filling rate in this invention is measured by the method as described in the Example mentioned later.

  The plate-shaped molded body of the present invention can ensure excellent lightness due to the gaps generated between the fibers. These voids are breathable because they are continuous rather than independent voids unlike a resin foam such as sponge. Such a structure is a structure that is extremely difficult to produce by conventional hardening methods such as a method of impregnating a resin and a method of forming a film-like structure by closely adhering surface portions. .

That is, the plate-shaped molded product of the present invention has a low density, specifically an apparent density of, for example, 0.05 to 0.7 g / cm ^3. 0.06 to 0.45 g / cm ³ , preferably 0.08 to 0.38 g / cm ³ , and more preferably 0.1 to 0.33 g / cm ³ . In applications where hardness is required rather than lightweight, the apparent density is, for example, 0.2 to 0.7 g / cm ³ , preferably 0.25 to 0.65 g / cm ³ , and more preferably 0.3 to It may be about 0.6 g / cm ³ . If the apparent density is too low, it is lightweight, but it is difficult to ensure sufficient bending hardness and surface hardness. Conversely, if it is too high, the hardness can be ensured, but the lightness is reduced. When the density decreases, the fibers become entangled and become close to a general non-woven fiber structure that is merely fused at the intersection point. On the other hand, when the density is increased, the fibers are fused in a bundle shape, resulting in a porous plate shape. The structure is close to that of a molded body.

The basis weight of the plate-shaped molded body of the present invention can be selected from the range of, for example, about 50 to 10000 g / cm ² , preferably 150 to 8000 g / cm ² , and more preferably about 300 to 6000 g / m ² . In applications where hardness than light weight is required and a basis weight, for example, 1000~10000g / ^{m 2,} preferably 1500~8000g / ^{m 2,} more preferably about 2000~6000g / ^{m 2.} If the basis weight is too small, it is difficult to secure 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 uniformity in the thickness direction May decrease.

  The thickness of the plate-shaped molded product of the present invention is not particularly limited, but can be selected from a range of about 1 to 100 mm, for example, 3 to 100 mm, preferably 3 to 50 mm, more preferably 5 to 50 mm (particularly 5 to 30 mm). Degree. If the thickness is too thin, it will be difficult to ensure the hardness, and if it is too thick, the mass will also become heavy, so the handling properties as a sheet will be reduced.

(Manufacturing method of plate-like molded product)
In the invention, an example of using a wet heat adhesive biodegradable polymer is shown as an example of a method for producing a plate-like molded body. First, the fiber containing the fiber which has a biodegradable polymer at least on the surface is web-formed. 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 airlay 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 cross-wrap web, and the like. Of these webs, a semi-random web and a parallel web are preferred when the proportion of bundled fused fibers is increased.

  Next, the obtained fiber web is sent to the next process by a belt conveyor, and then exposed to superheated or high-temperature steam (high-pressure steam) flow, thereby obtaining a plate-like molded body having a non-woven fiber structure in the present invention. It is done. That is, when the fiber web transported by the belt conveyor passes through the high-speed high-temperature steam flow ejected from the nozzle of the steam spraying device, the fibers are three-dimensionally bonded to each other by the sprayed high-temperature steam.

  The belt conveyor to be used is not particularly limited as long as it can be subjected to high-temperature steam treatment while compressing the fiber web used for processing to a desired density, and an endless conveyor is preferably used. In addition, it may be a general single belt conveyor, or may be transported by combining two belt conveyors as necessary and sandwiching the web between both belts. By carrying in this way, when processing a web, it can suppress that the form of the web conveyed by external forces, such as the water used for a process, high temperature steam, and a conveyor's vibration, changes. It is also possible to suppress the density and thickness of the processed non-woven fibers by adjusting the distance between the belts.

  When two belt conveyors are combined, a steam injection device for supplying steam to the web is mounted in one conveyor and supplies steam to the web through a conveyor net. A suction box may be attached to the opposite conveyor. The suction box can suck and discharge excess steam that has passed through the web. In addition, in order to uniformly steam the front and back sides of the web, a suction box is further installed in the downstream part of the conveyor on the side where the steam injection device is installed, and the conveyor on the opposite side where this suction box is installed. A steam injection device may be installed inside. When there is no downstream steam injection device and suction box, if the front and back of the fiber web are to be steamed, the front and back of the fiber web once treated can be reversed and passed through the treatment device again.

  The endless belt used for the conveyor is not particularly limited as long as it does not hinder the conveyance of the 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 plate-like molded body having a flat surface, a net with a fine mesh may be used. Note that the upper limit is about 90 mesh, and a fine mesh with a mesh larger than this has low air permeability and makes it difficult for steam to pass through. The mesh belt is made of metal, heat-treated polyester resin, polyphenylene sulfide resin, polyarylate resin (fully aromatic polyester resin), aromatic polyamide resin, from the viewpoint of heat resistance against steam treatment, etc. Moist heat resistant resins such as polyether ketone resins are preferred.

  Since the high-temperature steam jetted from the steam jetting apparatus is an air stream, unlike the hydroentanglement process or the needle punch process, the high-temperature steam enters the inside of the web without largely moving the fibers in the web that is the object to be treated. It is considered that the inflow action and the wet heat action of the steam flow into the web efficiently cover the surface of each fiber existing in the web in a wet heat state, thereby enabling uniform thermal bonding. In addition, since this treatment is performed in a very short time under a high-speed air stream, the heat conduction to the fiber surface is sufficient, but the treatment ends before the heat conduction to the inside of the fiber is sufficient. For this reason, the entire fiber web to be treated is not easily crushed or deformed such that its thickness is impaired by the pressure or heat of high-temperature steam. As a result, wet heat bonding is completed so that the degree of bonding in the surface and the thickness direction is substantially uniform without causing large deformation in the fiber web.

Furthermore, when obtaining a plate-shaped molded article having a high surface hardness and high bending strength, when the high-temperature steam is supplied to the web for processing, the target web is subjected to a desired apparent density (for example, between conveyor belts or rollers). , About 0.2 to 0.7 g / cm ³ ) and is exposed to high-temperature steam in a compressed state. In particular, when trying to obtain a relatively high-density plate-like molded body, it is necessary to compress the fiber web with sufficient pressure when processing with high-temperature steam. Furthermore, it is possible to adjust to a target thickness or density by securing an appropriate clearance between rollers or between conveyors. In the case of a conveyor, since it is difficult to compress the web at a stretch, it is preferable to set the belt tension as high as possible and gradually narrow the clearance from the upstream of the steam treatment point. Furthermore, it is processed into a plate-like molded body having desired bending hardness, surface hardness, lightness, and air permeability by adjusting the steam pressure and the processing speed.

  At this time, if it is desired to increase the hardness, the back side of the endless belt on the opposite side of the nozzle across the web is made of a stainless steel plate or the like so that the steam cannot pass through. Since it reflects here, it adhere | attaches more firmly by the heat retention effect of vapor | steam. Conversely, when light adhesion is required, a suction box may be provided to discharge excess water vapor to the outside.

  The nozzle for injecting the high-temperature water vapor may be a plate or 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 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 arranged 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 orifice diameter and pitch are not particularly limited as long as the target fiber fixation is possible, but the orifice diameter is usually 0.05 to 2 mm, preferably 0.1 to 1 mm, more preferably. It is about 0.2 to 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. When the diameter of the orifice is too small, the processing accuracy of the nozzle is lowered, and the equipment problem that the processing becomes difficult and the operational problem that clogging is likely to occur are likely to occur. On the other hand, if it is too large, the steam injection force is reduced. 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, when the pitch is too large, there is a case where high-temperature water vapor does not sufficiently hit the web, so that the web strength is lowered.

  The high-temperature steam is not particularly limited as long as the target fiber fixation can be realized, and may be set according to the material and form of the fiber to be used. The pressure is, for example, 0.1 to 2 MPa, preferably 0.2 to 1. 0.5 MPa, more preferably about 0.3 to 1 MPa. If the pressure of the steam is too high or too strong, the fibers forming the web may move and cause disturbance of the formation, or the fibers may melt too much to partially retain the fiber shape. Also, if the pressure is too weak, it may not be possible to give the web the amount of heat necessary for fiber fusion, or water vapor may not penetrate the web, resulting in fiber fusion spots in the thickness direction. It may be difficult to control the uniform jet of steam.

  The temperature of the high-temperature steam is, for example, about 70 to 150 ° C, preferably about 80 to 120 ° C, and more preferably about 90 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, it is also possible to give a design property to a board product obtained by giving predetermined uneven patterns, letters, pictures, etc. to the conveyor belt and transferring them. Further, it may be laminated with other materials to form a laminated body, or may be processed into a desired shape (various shapes such as a cylindrical shape, a quadrangular prism shape, a spherical shape, an elliptical shape) by molding.

  After the fibers of the fiber web are partially wet-heat bonded in this way, moisture may remain in the resulting plate-like molded article having the nonwoven fiber structure, and the web may be dried as necessary. . As for drying, it is necessary that the surface of the plate-shaped molded body in contact with the heating body for drying does not lose its fiber form due to fiber melting after drying, and a conventional method can be used as long as the fiber form can be maintained. . For example, a large dryer such as a cylinder dryer or tenter used for drying nonwoven fabrics may be used, but the remaining moisture is very small and can be dried by a relatively light drying means. Therefore, a non-contact method such as far-infrared irradiation, microwave irradiation, electron beam irradiation, or a method using hot air is preferable.

  Furthermore, as described above, the plate-like molded body of the present invention is obtained by adhering fibers having a wet heat adhesive biodegradable polymer on the surface with high temperature steam, but partially (obtained by wet heat adhesion). Even if bonded by a processing method such as partial hot-pressure fusion (such as hot embossing) or mechanical compression (such as needle punching). Good.

  It is to be noted that wet heat adhesive fibers can be fused by immersing the fiber web in hot water. However, it is difficult to control the fiber adhesion rate by such a method, and the plate-like molded body having high uniformity of the fiber adhesion rate. Is difficult to get. The reason for this is that the wet heat adhesiveness differs depending on the position due to the air contained in the fiber web, the influence on the structure caused by this air being pushed out of the fiber web, the wet heat bonded fiber web It is presumed that the deformation of the fine structure inside the fiber by the take-off roller when taking out from the hot water or the difference in the deformation of the fine structure in the vertical direction due to the weight of the hot water contained in the picked-up fiber web.

  The plate-like molded article having a nonwoven fiber structure obtained in this way has extremely high bending stress and surface hardness while having a low density comparable to that of a general nonwoven fabric, and also has air permeability. is doing. Therefore, using such performance, for example, various board materials such as wood and control panel have been used conventionally, or performance such as breathability, heat insulation, and sound absorption for these board materials. Can be applied to applications that are required simultaneously. Specifically, a building material board, a heat insulating material or a heat insulating board, a breathable board, a liquid-absorbing material (a core such as a magic pen or a fluorescent pen, an ink holding material for an ink jet printer cartridge, or a core material for fragrances such as a fragrance) Etc.), sound absorbers (sound insulation wall materials, vehicle sound insulation materials, etc.), work materials, cushion materials, lightweight containers and partition materials, wiping materials (whiteboard erasers, dishwashing sponges, pen-type wipers, etc.).

  Furthermore, since the plate-like molded product of the present invention has high air permeability, for example, even if a decorative film is bonded to the plate-shaped molded product, the air surrounded between the decorative film and the plate-shaped molded product is opposite. Since it comes out to the side, the floating and peeling of the film accompanying the film sticking can be avoided. Further, the adhesive material of the attached film sticks to the constituent fibers on the surface of the plate-like molded body, and strong adhesion can be realized by entering like a wedge of the fiber gap.

  Moreover, when the plate-shaped molded body of the present invention is used as a container, the inside and outside of the container can be exchanged with air, and the container can be used as a container for transporting breathing organisms and substances.

  Furthermore, when a flame retardant is contained, it can also be used for applications requiring flame retardancy, such as automobile interior materials, aircraft inner wall materials, building materials, furniture, and the like.

  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 )
It measured according to JIS L1913.

(2) Thickness and apparent density (g / cm ³ )
The thickness was measured according to JIS L1913, and the apparent density was calculated from this value and the basis weight value.

(3) Fiber adhesion rate Using a scanning electron microscope (SEM), a photograph was taken in which the cross section of the plate-like molded body was enlarged 100 times. The cross-sectional photograph of the photographed plate-shaped molded product in the thickness direction is divided into three equal parts in the thickness direction, and the fiber cut surface (fiber end face) that can be found in each of the three divided areas (front surface, inside (center), back surface) The ratio of the number of cut surfaces where the fibers are bonded to each other was determined. Of the total number of fiber cross sections that can be found in each region, the ratio of the number of cross sections in a state where two or more fibers are bonded is expressed as a percentage based on the following formula. In addition, in the part which fibers contact, there exists a part which is simply contacting, without melt | fusion, and a part which has adhere | attached by melt | fusion. However, by cutting the plate-shaped molded body for microscopic photography, the fibers in contact with each other are separated from each other by the stress of each fiber on the cut surface of the plate-shaped molded body. Therefore, in the cross-sectional photograph, it can be determined that the contacting fibers are bonded to each other.

Fiber adhesion rate (%) = (number of cross sections of fibers bonded two or more) / (total number of cross sections of fibers) × 100
However, for each photograph, all the fibers with visible cross sections were counted, and when the number of fiber cross sections was 100 or less, a photograph to be observed was added so that the total fiber cross section number exceeded 100. In addition, the fiber adhesion rate was calculated | required about each area | region divided into three equally, and the difference of the maximum value and minimum value was also calculated | required together.

(4) Shape retention of non-woven fiber pieces Non-woven fiber samples were cut into 5 mm square cubes and charged into Erlenmeyer flasks (100 cm ³ ) containing 50 cm ³ of water. This flask was attached to a shaker (manufactured by Yamato Scientific Co., Ltd., “MK160 type”), and was shaken for 30 minutes at a speed of 60 rpm in a shallow sea method with an amplitude of 30 mm. After shaking, the morphological change and morphological retention state were visually observed and evaluated in three stages according to the following criteria.
◎: Preserving the shape before processing ○: Large missing part is not seen, but there is a change in shape ×: Occurrence of missing part is seen

Example 1
A polylactic acid fiber, a fineness of 2 dtex, and a fiber length of 51 mm were prepared as biodegradable fibers. Using this fiber, a card web having a basis weight of about 100 g / m ² was prepared by a card method, and seven sheets of this web were stacked to form a card web having a total basis weight of 700 g / m ² . The card web was transferred to a belt conveyor equipped with a 50 mesh, 500 mm wide stainless steel endless net.

  This belt conveyor is composed of a pair of conveyors, a lower conveyor and an upper conveyor, and a steam injection nozzle is installed on the back side of the belt of at least one of the conveyors so that high-temperature steam can be injected onto the passing web through the belt. is there. Further, a metal roll for adjusting the web thickness (hereinafter sometimes abbreviated as “web thickness adjusting roll”) is provided upstream of the nozzle. The lower conveyor has a flat upper surface (ie, the surface through which the web passes), and one upper conveyor has a lower surface bent along a web thickness adjusting roll for adjusting the web thickness of the upper conveyor. The rolls are arranged to make a pair with the web thickness adjusting roll of the lower conveyor.

  Further, the upper conveyor can be moved up and down, whereby the distance between the web thickness adjusting rolls of the upper conveyor and the lower conveyor can be adjusted to a predetermined interval. Further, the upstream side of the upper conveyor is inclined at an angle of 30 degrees (relative to the lower surface on the downstream side of the upper conveyor) with respect to the downstream portion with respect to the web thickness adjusting roll, and the downstream portion is parallel to the lower conveyor. It is bent so that it may be arranged. When the upper conveyor moves up and down, it moves while maintaining this parallel relationship.

  Each of these belt conveyors rotates in the same direction at the same speed, and the two conveyor belts and the web thickness adjusting rolls can be pressurized while maintaining a predetermined clearance. This is for adjusting the web thickness before steaming by operating like a so-called calendar process. That is, the card web fed from the upstream side travels on the lower conveyor, but the interval with the upper conveyor is gradually narrowed before reaching the web thickness adjusting roll. And when this space | interval becomes narrower than web thickness, a web is pinched | interposed between an up-and-down conveyor belt, and it drive | works while being compressed gradually. This web is compressed to a thickness approximately equal to the clearance provided on the web thickness adjusting roll, steam-treated in that thickness state, and then running while maintaining the thickness downstream of the conveyor. It is a mechanism to do. Here, the roll for adjusting the web thickness was adjusted to have a linear pressure of 50 kg / cm.

  Next, the card web is introduced into a steam jetting device provided in the lower conveyor, and 0.4 MPa high-temperature steam is jetted (perpendicularly) so as to pass in the thickness direction of the card web from this device. The molded body which has processed and obtained the nonwoven fiber structure of this invention was obtained. In this steam injection device, a nozzle is installed in the lower conveyor so as to blow high temperature steam toward the web through 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 vapor | steam injection nozzle was 0.3 mm, and the vapor | steam injection apparatus with which the nozzle was arranged in 1 row at 1 mm pitch along the width direction of a conveyor was used. The processing speed was 3 m / min, and the interval (distance) between the upper and lower conveyor belts on the nozzle side and the suction side was 10 mm. The nozzles were arranged so as to be almost in contact with the back side of the conveyor belt.

Example 2
Seven layers using a card web having a basis weight of about 100 g / m ² in which 70 parts of the biodegradable polylactic acid fiber used in Example 1 and 30 parts of rayon fiber (fineness: 1.4 dtex, fiber length: 44 mm) are mixed. Except for the above, a molded product of the present invention was obtained in the same manner as in Example 1. The results are shown in Table 1.

Example 3
Seven layers using a card web having a basis weight of about 100 g / m ² in which 50 parts of the biodegradable polylactic acid fiber used in Example 1 and 50 parts of rayon fiber (fineness: 1.4 dtex, fiber length: 44 mm) are mixed. Except for the above, a molded product of the present invention was obtained in the same manner as in Example 1. The results are shown in Table 1.

Example 4
Seven layers using a card web with a basis weight of about 100 g / m ² in which 30 parts of the biodegradable polylactic acid fiber used in Example 1 and 70 parts of rayon fiber (fineness: 1.4 dtex, fiber length: 44 mm) are mixed. Except for the above, a molded product of the present invention was obtained in the same manner as in Example 1. The results are shown in Table 1.

Example 5
Seven layers are laminated using a card web having a basis weight of about 100 g / m ² in which 70 parts of the biodegradable polylactic acid fiber used in Example 1 and 30 parts of polyethylene terephthalate fiber (fineness 2 dtex, fiber length 51 mm) are mixed. Except for this, the molded product of the present invention was obtained in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1
7 layers using a card web having a basis weight of about 100 g / m ² in which 8 parts of the biodegradable polylactic acid fiber used in Example 1 and 92 parts of rayon fiber (fineness: 1.4 dtex, fiber length: 44 mm) are mixed. Except for the above, a molded product of the present invention was obtained in the same manner as in Example 1. The results are shown in Table 1. Adhesive strength between fibers could not be obtained, and dropout was observed in the form.

Comparative Example 2
A molded article of the present invention was obtained in the same manner as in Example 1 except that seven sheets were stacked using a card web having a basis weight of about 100 g / m ² produced only with the polyethylene terephthalate fiber used in Example 5. The results are shown in Table 1. Sufficient adhesion between the fibers could not be obtained, and the web was almost in a web state and could not be easily transported alone.

Claims (11)

It is a plate-shaped molded article that includes fibers having at least the surface of a biodegradable polymer and has a nonwoven fiber structure, and is bonded at a fiber adhesion rate of 5 to 85% by fusion of the biodegradable polymer. A plate-like molded body having an apparent density of 0.05 to 0.7 g / cm ³ integrated. In the cross section in the thickness direction, the fiber adhesion rate in each region divided in three in the thickness direction is 85% or less, and the difference between the maximum value and the minimum value of the fiber adhesion rate in each region is 20%. The plate-shaped molded article according to claim 1, which is as follows. In the cross section in the thickness direction, the fiber filling rate in each region divided in three in the thickness direction is 20 to 80%, and the difference between the maximum value and the minimum value of the fiber filling rate in each region is 20%. The plate-shaped molded product according to claim 1 or 2, wherein the molded product is at most%. The plate-shaped molded article according to any one of claims 1 to 3, wherein a weight ratio of the biodegradable polymer to the whole is 10% or more. The plate-shaped molded article according to any one of claims 1 to 4, wherein the biodegradable polymer contains fibers that are a single polymer component. The plate-shaped molded article according to any one of claims 1 to 5, comprising a composite fiber composed of two or more kinds of polymer components, all of which are biodegradable polymers. It consists of two or more types of polymer components, contains at least one type of biodegradable polymer, and the remaining components contain a composite fiber that is a thermoplastic polymer. The plate-shaped molded object of Claim 1. The plate-shaped molded article according to any one of claims 1 to 7, wherein the biodegradable polymer is polylactic acid. The plate-shaped molded product according to any one of claims 1 to 8, comprising at least one selected from the group consisting of a boron-based flame retardant and a silicon-based flame retardant. It is a heat insulating and / or air permeable plate-shaped molded object, The plate-shaped molded object of any one of Claims 1-9. The board for building materials comprised with the plate-shaped molded object of any one of Claims 1-10.