Method for producing non-woven fabric and melt-blown non-woven fabric, hot-melted body and method for producing same, coffee filter, and coffee capsule

Abstract

The present invention relates to a non-woven fabric formed from fibers each containing a poly(3-hydroxyalkanoate)-based resin, and provides a non-woven fabric and the like having an excellent property of being hot-melted to other materials. The present invention provides: a non-woven fabric containing fibers, in which the fibers are formed from a resin composition containing a poly(3-hydroxyalkanoate)-based resin, the poly(3-hydroxyalkanoate)-based resin contains a 3-hydroxybutyrate unit, the content ratio of the 3-hydroxybutyrate unit in the poly(3-hydroxyalkanoate)-based resin contained in the non-woven fabric is 91.0 mol% to 97.0 mol% inclusive, and the amount of heat of melting of an endothermic peak in a DSC curve of the non-woven fabric is 50.0 J / g or more; and the like.

Description

Manufacturing method of nonwoven fabric and meltblown nonwoven fabric, heat-sealed body and manufacturing method thereof, coffee filter, and coffee capsule

[0001] The present invention relates to a method for producing a nonwoven fabric and a meltblown nonwoven fabric, a heat-sealed product and a method for producing the same, a coffee filter, and a coffee capsule.

[0002] Meltblown nonwoven fabrics are nonwoven fabrics obtained by the meltblowing method, in which a polymer and hot air are extruded together from a spinneret. Meltblown nonwoven fabrics have a microporous structure. Nonwoven fabrics such as meltblown nonwoven fabrics are used, for example, as materials for constituting filters that capture particles. Examples of such filters include removal filters (including mask filters and filtration filters) that remove particles (e.g., particles with viruses or the like attached, pollen, etc.), blood filters that capture blood cells, and filters for beverage extraction (e.g., coffee drip filters, tea bags, etc.) (see, for example, Patent Document 1).

[0003] A coffee capsule including a capsule body and a lid is also known (see, for example, Patent Document 2). The capsule body is made of polylactic acid (PLA), and the lid includes a nonwoven fabric material formed from PLA fibers.

[0004] As fibers constituting nonwoven fabrics, fibers containing poly(hydroxyalkanoate) resins, which are biodegradable resins, are used from the viewpoint of reducing the burden on the global environment (for example, Patent Document 3).

[0005] JP 2022-505070 A JP 2019-517959 A JP 2022 / 097528 A

[0006] Incidentally, heat-fused articles formed by heat-fusing a nonwoven fabric made of fibers containing a polylactic acid resin with a nonwoven fabric made of fibers containing a cellulose resin are used as coffee filters, etc. Here, poly(3-hydroxyalkanoate) resins are more biodegradable than polylactic acid resins. Therefore, the present inventors attempted to produce heat-fused articles using nonwoven fabric made of fibers containing a poly(3-hydroxyalkanoate) resin instead of a nonwoven fabric made of fibers containing a polylactic acid resin.

[0007] However, conventional nonwoven fabrics formed from fibers containing poly(3-hydroxyalkanoate) resins were not sufficiently heat-sealed to nonwoven fabrics formed from fibers containing cellulose resins.

[0008] Furthermore, a heat-fused article in which a nonwoven fabric containing fibers and a molded article are heat-fused is used as the coffee capsule. The nonwoven fabric may be a nonwoven fabric containing fibers containing a polylactic acid-based resin. The molded article may be a molded article formed from a resin composition containing a poly(3-hydroxyalkanoate)-based resin.

[0009] As mentioned above, since poly(3-hydroxyalkanoate) resins are more biodegradable than polylactic acid resins, the present inventors also attempted to produce a heat-fused article using a nonwoven fabric formed from fibers containing poly(3-hydroxyalkanoate) resin instead of a nonwoven fabric formed from fibers containing polylactic acid resin.

[0010] However, the nonwoven fabric formed from fibers containing a poly(3-hydroxyalkanoate) resin and the molded article containing a poly(3-hydroxyalkanoate) resin were not sufficiently heat-sealed.

[0011] Therefore, the present invention relates to a nonwoven fabric formed from fibers containing a poly(3-hydroxyalkanoate) resin, and its first objective is to provide a nonwoven fabric that has excellent thermal adhesion to other materials (e.g., a nonwoven fabric containing cellulose-based fibers, a molded article containing a poly(3-hydroxyalkanoate) resin, etc.). A second objective of the present invention is to provide a heat-sealed article formed by heat-sealing the nonwoven fabric with a nonwoven fabric containing cellulose-based fibers or a molded article containing a poly(3-hydroxyalkanoate) resin. A third objective of the present invention is to provide a coffee filter or coffee capsule formed from the heat-sealed article.

[0012] A first aspect of the present invention relates to a nonwoven fabric containing fibers, wherein the fibers are formed from a resin composition containing a poly(3-hydroxyalkanoate)-based resin, the poly(3-hydroxyalkanoate)-based resin contains 3-hydroxybutyrate units, the content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate)-based resin contained in the nonwoven fabric is 91.0 mol % or more and 97.0 mol % or less, and the heat of fusion of an endothermic peak in a DSC curve of the nonwoven fabric is 50.0 J / g or more.

[0013] A second aspect of the present invention relates to a heat-fused article obtained by heat-fusing the nonwoven fabric described above with a nonwoven fabric containing cellulosic fibers.

[0014] A third aspect of the present invention relates to a coffee filter formed from the heat-sealable product.

[0015] A fourth aspect of the present invention is a heat-fused product obtained by heat-fusing a nonwoven fabric containing fibers to a molded product, wherein the fibers are formed from a first resin composition containing a poly(3-hydroxyalkanoate)-based resin, and the molded product is formed from a second resin composition containing a poly(3-hydroxyalkanoate)-based resin, and the value obtained by subtracting the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric from the heat of fusion of the endothermic peak in the DSC curve of the molded product is 2.5 J / g or more, and the nonwoven fabric is the first nonwoven fabric of the present invention.

[0016] Preferably, the heat-sealed body is a container comprising a container body having an opening and a lid body that closes the opening, the container body being the molded body, the lid body having the nonwoven fabric, and the nonwoven fabric and the molded body being heat-sealed at the opening.

[0017] A fifth aspect of the present invention is a coffee capsule comprising the heat-sealable body, the container body having an internal space, and coffee powder contained in the internal space.

[0018] A sixth aspect of the present invention is a method for producing a heat-fused article, comprising heat-fusing a nonwoven fabric containing fibers to a molded article to obtain the heat-fused article, wherein the fibers are formed from a first resin composition containing a poly(3-hydroxyalkanoate)-based resin, and the molded article is formed from a second resin composition containing a poly(3-hydroxyalkanoate)-based resin, and the value obtained by subtracting the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric from the heat of fusion of the endothermic peak in the DSC curve of the molded article is 2.5 J / g or more, and the nonwoven fabric is the first nonwoven fabric of the present invention.

[0019] A seventh aspect of the present invention relates to a method for producing a meltblown nonwoven fabric, in which a meltblown nonwoven fabric containing fibers is produced using a nozzle having nozzle holes, the method comprising: a step (A) of obtaining a raw yarn by discharging a molten material from the nozzle holes; and a step (B) of stretching the raw yarn by blowing a gas onto the raw yarn, wherein the molten material contains a poly(3-hydroxyalkanoate)-based resin, the poly(3-hydroxyalkanoate)-based resin contains 3-hydroxybutyrate units, the content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate)-based resin contained in the molten material is 91.0 mol% or more and 97.0 mol% or less, and in the step (B), the flow rate of the gas blown onto the raw yarn is 900 NL / min / 600 mm or more.

[0020] According to the present invention, a nonwoven fabric formed from fibers containing a poly(3-hydroxyalkanoate) resin can be provided, which has excellent thermal adhesion to other materials. The present invention also provides a heat-fused article formed by heat-fusing the nonwoven fabric with a nonwoven fabric containing cellulose fibers or a molded article containing a poly(3-hydroxyalkanoate) resin. Furthermore, the present invention also provides a coffee filter or coffee capsule formed from the heat-fused article.

[0021] Schematic cross-sectional view of a container. Schematic diagram of a nonwoven fabric manufacturing apparatus. Schematic perspective view of a nozzle. Schematic cross-sectional view of a nozzle hole and a conveyor belt. DSC curve of the nonwoven fabric of Example 2. Side view of heat-fused bodies of Examples and Comparative Examples. Plan view of heat-fused bodies of Examples and Comparative Examples. DSC curve of a molded body.

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0023] <Nonwoven Fabric> First, the nonwoven fabric according to this embodiment will be described. The nonwoven fabric according to this embodiment contains fibers. The fibers are formed from a resin composition (hereinafter also referred to as a "first resin composition") containing a poly(3-hydroxyalkanoate)-based resin. The poly(3-hydroxyalkanoate)-based resin contains 3-hydroxybutyrate units. The content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate)-based resin contained in the nonwoven fabric is 91.0 mol% or more and 97.0 mol% or less. The heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric is 50.0 J / g or more.

[0024] The first resin composition contains a polymer component. The first resin composition may further contain an additive.

[0025] The polymer component contains a poly(3-hydroxyalkanoate)-based resin. The polymer component may contain other polymers in addition to the poly(3-hydroxyalkanoate)-based resin.

[0026] The poly(3-hydroxyalkanoate) resin is a polyester containing 3-hydroxyalkanoic acid as a monomer. That is, the poly(3-hydroxyalkanoate) resin is a resin containing 3-hydroxyalkanoic acid as a structural unit. The poly(3-hydroxyalkanoate) resin is also a polymer having biodegradability. Note that, in this embodiment, "biodegradability" refers to the property of being decomposed into low molecular weight compounds by microorganisms in nature. Specifically, the presence or absence of biodegradability can be determined based on tests suited to each environment, such as ISO 14855 (compost) and ISO 14851 (activated sludge) under aerobic conditions, and ISO 14853 (aqueous phase) and ISO 15985 (solid phase) under anaerobic conditions. The decomposition ability of microorganisms in seawater can be evaluated by measuring the biochemical oxygen demand.

[0027] The poly(3-hydroxyalkanoate) resin contains a 3-hydroxybutyrate unit. That is, the poly(3-hydroxyalkanoate) resin contains a polymer having a 3-hydroxybutyrate unit. The polymer having a 3-hydroxybutyrate unit preferably contains a copolymer having a 3-hydroxybutyrate unit. The polymer having a 3-hydroxybutyrate unit may contain a homopolymer (P3HB).

[0028] In the copolymer having a 3-hydroxybutyrate unit, examples of the monomer unit other than the 3-hydroxybutyrate unit include a hydroxyalkanoate unit other than the 3-hydroxybutyrate unit, etc. Examples of the hydroxyalkanoate unit other than the 3-hydroxybutyrate unit include 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxyoctadecanoate, 3-hydroxyvalerate, and 4-hydroxybutyrate.

[0029] Examples of copolymers having 3-hydroxybutyrate units include P3HB3HH, P3HB3HV, P3HB4HB, poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), and poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate). Here, P3HB3HH means poly(3-hydroxybutyrate-co-3-hydroxyhexanoate). P3HB3HV means poly(3-hydroxybutyrate-co-3-hydroxyvalerate). P3HB4HB means poly(3-hydroxybutyrate-co-4-hydroxybutyrate). The poly(3-hydroxyalkanoate) resin may contain only one copolymer having 3-hydroxybutyrate units, or may contain two or more copolymers having 3-hydroxybutyrate units. P3HB3HH is preferred as the copolymer having 3-hydroxybutyrate units.

[0030] The first resin composition contains preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more of a polymer having a 3-hydroxybutyrate unit. The first resin composition also contains preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more of a copolymer having a 3-hydroxybutyrate unit.

[0031] The content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin is 91.0 mol% or more and 97.0 mol% or less, preferably 91.5 mol% or more and 96.5 mol% or less, and more preferably 92.0 mol% or more and 96.0 mol% or less. When the content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin is 91.0 mol% or more, the crystallinity of the fibers is increased, resulting in increased rigidity of the fibers. When the content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin is 97.0 mol% or less, the nonwoven fabric according to this embodiment has a high elongation at break, making the nonwoven fabric less likely to tear. Furthermore, when the content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin is 97.0 mol% or less, the nonwoven fabric according to this embodiment is less likely to fluff. The content ratio of the 3-hydroxybutyrate unit in the poly(3-hydroxyalkanoate) resin means the content ratio of the 3-hydroxybutyrate unit in the entire poly(3-hydroxyalkanoate) resin contained in the nonwoven fabric.

[0032] The content of 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin can be determined by the method described in the examples below.

[0033] Furthermore, the content of 3-hydroxybutyrate units in the entire poly(3-hydroxyalkanoate) resin contained in the first raw material composition (the "first raw material composition" will be described later) may be used as the content of 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin of the nonwoven fabric.

[0034] Examples of poly(3-hydroxyalkanoate) resins other than polymers having 3-hydroxybutyrate units include poly(3-hydroxyvalerate) and poly(3-hydroxyhexanoate).

[0035] P3HB has the function of promoting the crystallization of P3HB itself and poly(3-hydroxyalkanoate) resins other than P3HB.

[0036] The other polymer is preferably biodegradable.

[0037] Examples of other biodegradable polymers include polycaprolactone, polylactic acid, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, polyethylene succinate, polyvinyl alcohol, polyglycolic acid, unmodified starch, modified starch, cellulose acetate, and chitosan. The polycaprolactone is a polymer obtained by ring-opening polymerization of ε-caprolactone. The first resin composition may contain one or more other polymers.

[0038] The nonwoven fabric according to this embodiment contains a biodegradable polymer, so that even if the nonwoven fabric is discarded in the environment, the nonwoven fabric is easily decomposed in the environment, thereby reducing the burden on the environment.

[0039] The first resin composition may further contain an additive.

[0040] Examples of additives include nucleating agents, lubricants, stabilizers (antioxidants, ultraviolet absorbers, etc.), colorants (dyes, pigments, etc.), plasticizers, inorganic fillers, organic fillers, antistatic agents, etc.

[0041] The first resin composition preferably contains a nucleating agent as an additive. The nucleating agent is a compound that can promote crystallization of the poly(3-hydroxyalkanoate) resin. The nucleating agent has a higher melting point than the poly(3-hydroxyalkanoate) resin. By containing the nucleating agent in the first resin composition, crystallization of the poly(3-hydroxyalkanoate) resin is promoted when producing a nonwoven fabric, making it difficult for adjacent fibers to fuse together. As a result, it becomes easier to reduce the coefficient of variation of the fiber diameter of the fibers. Examples of the crystal nucleating agent include inorganic substances (e.g., boron nitride, titanium oxide, talc, layered silicates, calcium carbonate, sodium chloride, metal phosphates, etc.); sugar alcohol compounds derived from natural products (e.g., pentaerythritol, erythritol, galactitol, mannitol, arabitol, etc.); polyvinyl alcohol; chitin; chitosan; polyethylene oxide; aliphatic carboxylates; aliphatic alcohols; aliphatic carboxylate esters; dicarboxylic acid derivatives (e.g., dimethyl adipate, dibutyl adipate, diisodecyl adipate, djibutyl adipate, etc.); Examples of suitable hydroxyalkanoate include sorbitol derivatives (e.g., bisbenzylidene sorbitol, bis(p-methylbenzylidene)sorbitol, etc.); cyclic compounds having C═O and a functional group selected from NH, S, and O in the molecule (e.g., indigo, quinacridone, quinacridone magenta, etc.); sorbitol derivatives (e.g., bisbenzylidene sorbitol, bis(p-methylbenzylidene)sorbitol, etc.); compounds containing a nitrogen-containing heteroaromatic nucleus (e.g., pyridine ring, triazine ring, imidazole ring, etc.) (e.g., pyridine, triazine, imidazole, etc.); phosphate ester compounds; bisamides of higher fatty acids; metal salts of higher fatty acids; and branched polylactic acid. The poly(3-hydroxyalkanoate) resin P3HB can also be used as a crystal nucleating agent. These may be used alone or in combination of two or more.

[0042] As the crystal nucleating agent, from the viewpoint of the effect of improving the crystallization rate of the poly(3-hydroxyalkanoate) resin and from the viewpoint of compatibility and affinity with the poly(3-hydroxyalkanoate) resin, sugar alcohol compounds, polyvinyl alcohol, chitin, and chitosan are preferred. Among the sugar alcohol compounds, pentaerythritol is preferred.

[0043] The nucleating agent preferably has a crystalline structure at room temperature (25°C). The nucleating agent having a crystalline structure at room temperature (25°C) has the advantage of further accelerating the crystallization of the poly(3-hydroxyalkanoate) resin. Furthermore, the nucleating agent having a crystalline structure at room temperature (25°C) is preferably in a powder form at room temperature (25°C). Furthermore, the average particle size of the nucleating agent in a powder form at room temperature (25°C) is preferably 10 μm or less.

[0044] The first resin composition contains a nucleating agent in an amount of preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more per 100 parts by mass of the poly(3-hydroxyalkanoate)-based resin. The first resin composition contains 0.1 parts by mass or more of the nucleating agent per 100 parts by mass of the poly(3-hydroxyalkanoate)-based resin, which has the advantage of further promoting crystallization of the poly(3-hydroxyalkanoate)-based resin when producing a nonwoven fabric. The first resin composition also contains 2.5 parts by mass or less, more preferably 2.0 parts by mass or less of the nucleating agent per 100 parts by mass of the poly(3-hydroxyalkanoate)-based resin. The first resin composition contains 2.5 parts by mass or less of the nucleating agent per 100 parts by mass of the poly(3-hydroxyalkanoate)-based resin, which has the advantage of making it easier to obtain fibers when producing a nonwoven fabric. It should be noted that P3HB is a poly(3-hydroxyalkanoate)-based resin and can also function as a crystal nucleating agent. Therefore, when the first resin composition contains P3HB, the amount of P3HB is included in both the amount of the poly(3-hydroxyalkanoate)-based resin and the amount of the crystal nucleating agent.

[0045] The first resin composition preferably contains the lubricant. When producing a nonwoven fabric, the lubricant in the fibers improves the lubricity of the fibers, thereby preventing fusion of the fibers. Examples of the lubricant include compounds having an amide bond. The compound having an amide bond preferably contains one or more compounds selected from lauric acid amide, myristic acid amide, stearic acid amide, behenic acid amide, and erucic acid amide.

[0046] The content of the lubricant in the first resin composition is preferably 0.05 parts by mass or more, more preferably 0.10 parts by mass or more, and even more preferably 0.5 parts by mass or more, per 100 parts by mass of the polymer component. Having the content of the lubricant in the first resin composition be 0.05 parts by mass or more per 100 parts by mass of the polymer component has the advantage of being able to further suppress fusion between fibers when producing a nonwoven fabric. Furthermore, the content of the lubricant in the first resin composition is preferably 12 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 8 parts by mass or less, and most preferably 5 parts by mass or less, per 100 parts by mass of the polymer component. Having the content of the lubricant in the first resin composition be 12 parts by mass or less per 100 parts by mass of the polymer component has the advantage of being able to suppress bleeding out of the lubricant onto the surface of the fibers.

[0047] The melt mass flow rate (MFR) of the first resin composition at 165°C is preferably 50 to 1500 g / 10 min, more preferably 70 to 1500 g / 10 min, still more preferably 80 to 1300 g / 10 min, and particularly preferably 80 to 1200 g / 10 min.

[0048] When the melt mass flow rate of the first resin composition in the fibers at 165°C is 1500 g / 10 min or less, the strength and elongation of the nonwoven fabric are increased. When the melt mass flow rate of the first resin composition in the fibers at 165°C is 50 g / 10 min or more, the tension applied to the fibrous molten material during stretching can be reduced, making it easier to reduce the fiber diameter of the fibers in the resulting nonwoven fabric.

[0049] The melt mass flow rate (MFR) of the first resin composition at 165 ° C. is determined by ASTM-D1238 (ISO1133-1, JIS K7210-1:2011) Method B. The melt volume flow rate (MVR) of the first resin composition at 165 ° C. is determined from the melt volume flow rate (MVR) of the first resin composition at 165 ° C. and the density of the resin composition. The melt volume flow rate (MVR) of the first resin composition at 165 ° C. is measured by heating 5 g or more of the first resin composition at 165 ° C. for 4 minutes and then applying a load of 5 kg to the heated first resin composition.

[0050] The weight average molecular weight of the first resin composition is preferably 100,000 to 250,000, more preferably 110,000 to 200,000, and even more preferably 110,000 to 180,000.

[0051] When the weight-average molecular weight of the first resin composition in the fibers is 100,000 or more, the strength and elongation of the nonwoven fabric are increased. When the weight-average molecular weight of the first resin composition in the fibers is 250,000 or less, the tension applied to the fibrous molten material during stretching can be reduced, making it easier to reduce the fiber diameter of the fibers in the resulting nonwoven fabric.

[0052] The weight-average molecular weight in this embodiment is measured from the polystyrene-equivalent molecular weight distribution using gel permeation chromatography (GPC) with chloroform as an eluent. A column suitable for measuring the molecular weight may be used for the GPC. The conditions for GPC measurement may be the same as those described in the Examples below.

[0053] The average fiber diameter of the fibers is preferably 3.3 μm or more, more preferably 3.3 to 15.0 μm, even more preferably 3.3 to 12.0 μm, and particularly preferably 3.3 to 10.0 μm. The coefficient of variation of the fiber diameter of the fibers is preferably 0.40 or less, more preferably 0.36 or less, and even more preferably 0.32 or less. The coefficient of variation of the fiber diameter of the fibers is, for example, 0.10 or more.

[0054] When the average fiber diameter of the fibers is 3.3 μm or more, the strength and elongation of the nonwoven fabric are increased. When the average fiber diameter of the fibers is 15.0 μm or less, the particle collection efficiency of the nonwoven fabric is increased. When the fiber diameter coefficient of variation of the fibers is 0.40 or less, extremely thick fibers are reduced, and the uniformity of the nonwoven fabric as a filter is improved, resulting in a further improvement in the particle collection efficiency of the nonwoven fabric. Furthermore, when the fiber diameter coefficient of variation of the fibers is 0.40 or less, extremely thin fibers are reduced, resulting in an increase in the tensile strength of the nonwoven fabric.

[0055] The average fiber diameter and coefficient of variation of the fibers can be determined as follows. First, a test piece is obtained from a nonwoven fabric. Next, photographs (1700x magnification) of five locations on the surface of the test piece are taken using a scanning electron microscope. Then, the diameters (widths) of 20 or more randomly selected fibers are measured for each photograph. Next, the arithmetic mean value and coefficient of variation (= standard deviation / arithmetic mean value) are determined from the diameter (width) values ​​of all the measured fibers.

[0056] The heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric according to this embodiment is 50.0 J / g or more, preferably 50.5 to 90.0 J / g, more preferably 51.0 to 70.0 J / g, and even more preferably 51.0 J / g or more but less than 64.5 J / g.

[0057] The nonwoven fabric according to this embodiment has a high crystallinity due to the heat of fusion of the endothermic peak in the DSC curve being 50.0 J / g or more. Therefore, even when the nonwoven fabric according to this embodiment is sufficiently heat-sealed to other materials (e.g., nonwoven fabrics containing cellulose-based fibers, molded articles containing poly(3-hydroxyalkanoate)-based resins, etc.), crystals remain at the interface, making it easier to maintain strength. In other words, the nonwoven fabric according to this embodiment has excellent heat-sealing properties with other materials (e.g., nonwoven fabrics containing cellulose-based fibers, molded articles containing poly(3-hydroxyalkanoate)-based resins, etc.).

[0058] In this embodiment, the heat of fusion of the endothermic peak in the DSC curve can be determined from the area of ​​the endothermic peak in the DSC curve according to the method described in JIS K7122-1987 "Method for measuring the heat of transition of plastics." The melting point of the molded product described below is the peak-top temperature of the endothermic peak in the DSC curve, determined according to the method described in JIS K7121-1987 "Method for measuring the transition temperature of plastics." Specifically, using a differential scanning calorimeter (e.g., a differential scanning calorimeter DSC25 manufactured by TA Instruments), approximately 6.5 mg of sample is filled into a measurement vessel, heated and cooled between -30°C and 180°C at a heating and cooling rate of 10°C / min under a nitrogen gas flow rate of 30 ml / min, and the area of ​​the endothermic peak during the second heating is measured, and the area of ​​the endothermic peak is taken as the heat of fusion of the endothermic peak. The temperature at the top of the endothermic peak during the second temperature increase is taken as the melting point of the molded product. When there are two or more endothermic peaks, the sum of the areas of all the endothermic peaks is taken as the heat of fusion of the endothermic peaks, and the temperature at the top of the endothermic peak on the highest temperature side is taken as the melting point of the molded product.

[0059] The basis weight of the nonwoven fabric according to this embodiment is preferably 20 to 80 g / m ２ , more preferably 25 to 77 g / m ２ , more preferably 30 to 75 g / m ２ The nonwoven fabric according to this embodiment has a basis weight of 20 g / m ２ By satisfying the above conditions, the strength and elongation of the nonwoven fabric are increased. ２By satisfying the above, the particle collection efficiency of the nonwoven fabric is further improved. ２ When the above ratio is 0.01 or less, the liquid permeability (water permeability, etc.) or breathability of the nonwoven fabric can be improved.

[0060] The basis weight of the nonwoven fabric according to this embodiment can be determined as follows. First, a test piece is obtained from the nonwoven fabric according to this embodiment. The size of the test piece can be, for example, 100 mm x 100 mm, 200 mm x 200 mm, etc. Next, the weight of the test piece is measured using an electronic balance or the like. Then, the basis weight is calculated by dividing the weight of the test piece by the area of ​​the test piece.

[0061] The thickness of the nonwoven fabric according to this embodiment is preferably 0.10 to 0.40 mm, more preferably 0.15 to 0.35 mm. Having a thickness of 0.10 to 0.40 mm makes it easier to obtain a homogeneous nonwoven fabric when producing the nonwoven fabric. Having a thickness of 0.10 mm or more increases the strength and elongation of the nonwoven fabric. Having a thickness of 0.10 to 0.40 mm makes it possible to increase the particle collection efficiency of the nonwoven fabric while also increasing the liquid permeability (such as water permeability) or breathability of the nonwoven fabric.

[0062] The thickness of the nonwoven fabric according to this embodiment can be determined by measuring the thickness of the nonwoven fabric at three or more points with a thickness meter, and taking the arithmetic mean value of the measured values. Examples of thickness meter include "PEACOCK" manufactured by Ozaki Seisakusho Co., Ltd.

[0063] Furthermore, the average pore size of the nonwoven fabric according to this embodiment is preferably 2.5 μm or more and 10.0 μm or less, more preferably 3.0 μm or more and 7.0 μm or less. When the average pore size of the nonwoven fabric according to this embodiment is 2.5 μm or more, the liquid permeability (water permeability, etc.) or breathability of the nonwoven fabric can be improved. When the average pore size of the nonwoven fabric according to this embodiment is 10.0 μm or less, the particle collection efficiency of the nonwoven fabric is further improved.

[0064] The average pore size of the nonwoven fabric according to this embodiment is the mean flow pore size determined in accordance with JIS K3832-1990 "Bubble point test method for microfiltration membrane elements and modules." The mean flow pore size can be measured using, for example, a Perm Porometer (manufactured by PMI).

[0065] The nonwoven fabric is preferably a direct-spun nonwoven fabric. The direct-spun nonwoven fabric means "a nonwoven fabric obtained by entangling raw yarns obtained by melt spinning to form a sheet directly and solidifying the raw yarns." Note that "intertwining raw yarns to form a sheet directly" means "entangling raw yarns to form a sheet before the raw yarns are solidified." Examples of the direct-spun nonwoven fabric include meltblown nonwoven fabrics, spunbond nonwoven fabrics, flash-spun nonwoven fabrics, and electrospun nonwoven fabrics. The meltblown nonwoven fabric is a nonwoven fabric obtained by the meltblown method. Note that the meltblown nonwoven fabric also includes nonwoven fabrics obtained by the Spunblown (registered trademark) method. The nonwoven fabric is more preferably a meltblown nonwoven fabric or a spunbond nonwoven fabric, and even more preferably a meltblown nonwoven fabric.

[0066] The maximum load in the MD direction of the nonwoven fabric according to this embodiment is preferably 0.7 N or more, more preferably 0.8 N or more, and even more preferably 0.9 N or more. The maximum load in the MD direction of the nonwoven fabric according to this embodiment is, for example, 10.0 N or less. When the maximum load in the MD direction of the nonwoven fabric according to this embodiment is 0.7 N or more, the nonwoven fabric according to this embodiment is less likely to tear even when pulled in the MD direction.

[0067] The maximum load in the CD direction of the nonwoven fabric according to this embodiment is preferably 0.7 N or more, more preferably 0.8 N or more, and even more preferably 0.9 N or more. The maximum load in the CD direction of the nonwoven fabric according to this embodiment is, for example, 10.0 N or less. When the maximum load in the CD direction of the nonwoven fabric according to this embodiment is 0.7 N or more, the nonwoven fabric according to this embodiment is less likely to tear even when pulled in the CD direction.

[0068] The tensile elongation at break in the MD direction (also simply referred to as "MD elongation") of the nonwoven fabric according to this embodiment is preferably 15% or more, more preferably 16% or more. The MD elongation of the nonwoven fabric according to this embodiment is, for example, 500% or less. When the MD elongation of the nonwoven fabric according to this embodiment is 15% or more, the nonwoven fabric according to this embodiment is less likely to break even when pulled in the MD direction.

[0069] The tensile elongation at break in the CD direction (also simply referred to as "CD elongation") of the nonwoven fabric according to this embodiment is preferably 15% or more, more preferably 16% or more. The CD elongation of the nonwoven fabric according to this embodiment is, for example, 500% or less. When the CD elongation of the nonwoven fabric according to this embodiment is 15% or more, the nonwoven fabric according to this embodiment is less likely to break even when pulled in the CD direction.

[0070] Here, the MD direction is the direction in which the nonwoven fabric moves when it is produced (machine direction). The CD direction is the direction perpendicular to the MD direction. The tensile elongation at break is also called the tensile elongation at break.

[0071] The maximum load and tensile elongation at break in the CD and MD directions can be determined by the method described in the Examples below.

[0072] Furthermore, two or more sheets of the nonwoven fabric according to this embodiment may be laminated together and used as a material for a filter, etc.

[0073] <Heat-sealed article according to the first embodiment> The heat-sealed article according to the first embodiment is formed by heat-sealing the nonwoven fabric according to this embodiment and a nonwoven fabric containing cellulosic fibers.

[0074] Examples of the cellulosic fibers include cotton fibers, rayon (a concept that also includes cupra (also known as "cuprammonium rayon")), acetate fibers, etc. The heat-sealed article according to the first embodiment has high particle collection efficiency due to the nonwoven fabric according to this embodiment, and the strength of the heat-sealed article is even higher due to the nonwoven fabric containing cellulosic fibers. Examples of the nonwoven fabric containing cellulosic fibers include spunlace nonwoven fabric.

[0075] When the nonwoven fabric according to this embodiment and the nonwoven fabric containing cellulosic fibers are heat-sealed, the nonwoven fabric is melted by heat.

[0076] In the heat-sealed article according to the first embodiment, the nonwoven fabric according to the present embodiment and the nonwoven fabric containing cellulosic fibers may be directly fused together. Furthermore, in the heat-sealed article according to the first embodiment, the nonwoven fabric according to the present embodiment and the nonwoven fabric containing cellulosic fibers may be fused together via another layer, for example, via a film layer formed of a film. Examples of materials constituting the film include polybutylene adipate.

[0077] The heat-fused article according to the first embodiment can be suitably used, for example, as a material for a filter that captures particles. Examples of the filter include filters for beverage extraction (for example, coffee drip filters, tea bags, etc.), removal filters for removing particles (for example, particles with viruses or the like attached, pollen, etc.) (for example, mask filters, etc.), and blood filters for capturing blood cells.

[0078] <Coffee Filter> The coffee filter according to this embodiment is formed from the heat-sealed article according to the first embodiment.

[0079] <Heat-fused article according to a second embodiment> The heat-fused article according to a second embodiment is a heat-fused article obtained by heat-fusing a nonwoven fabric containing fibers and a molded article. The fibers are formed from a first resin composition containing a poly(3-hydroxyalkanoate)-based resin. The molded article is formed from a second resin composition containing a poly(3-hydroxyalkanoate)-based resin. The value obtained by subtracting the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric from the heat of fusion of the endothermic peak in the DSC curve of the molded article is 2.5 J / g or more. The nonwoven fabric is the nonwoven fabric according to this embodiment.

[0080] The nonwoven fabric and the molded body are directly heat-sealed.

[0081] (Molded Article) The molded article is formed from a second resin composition containing a poly(3-hydroxyalkanoate)-based resin.

[0082] The second resin composition in the molded article contains a polymer component. The second resin composition may further contain an additive.

[0083] Examples of the polymer component constituting the second resin composition include those exemplified as the polymer component constituting the first resin composition.

[0084] The poly(3-hydroxyalkanoate) resin preferably contains a 3-hydroxybutyrate unit. The polymer containing a 3-hydroxybutyrate unit preferably contains a copolymer containing a 3-hydroxybutyrate unit. A preferred copolymer containing a 3-hydroxybutyrate unit is P3HB3HH.

[0085] The second resin composition contains preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more of a polymer having a 3-hydroxybutyrate unit. The second resin composition also contains preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more of a copolymer having a 3-hydroxybutyrate unit.

[0086] The content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin is preferably 88.0 mol% or more and 97.0 mol% or less, more preferably 89.0 mol% or more and 96.5 mol% or less, and even more preferably 91.0 mol% or more and 96.0 mol% or less. When the content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin is 88.0 mol% or more, the crystallinity of the molded body is increased, and the rigidity of the molded body is improved. When the content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin is 97.0 mol% or less, the elongation of the molded body is increased, and the flexibility of the molded body is improved, and the toughness of the molded body is increased. Note that the content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin means the content of the 3-hydroxybutyrate units in the entire poly(3-hydroxyalkanoate) resin contained in the molded body.

[0087] Furthermore, the content ratio of 3-hydroxybutyrate units in the entire poly(3-hydroxyalkanoate) resin contained in the second raw material composition (the "second raw material composition" will be described later) may be used as the content ratio of 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin of the molded article.

[0088] Examples of the additives constituting the second resin composition include those exemplified as additives constituting the first resin composition.

[0089] The weight average molecular weight of the second resin composition is preferably 100,000 to 250,000, more preferably 110,000 to 200,000, and even more preferably 110,000 to 180,000.

[0090] The value obtained by subtracting the heat of fusion of the endothermic peak in the DSC curve of the molded article from the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric is 2.5 J / g or more, preferably 3.0 J / g or more, more preferably 3.5 J / g or more, and even more preferably 3.7 J / g or more. The value obtained by subtracting the heat of fusion of the endothermic peak in the DSC curve of the molded article from the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric is, for example, 10.0 J / g or less, more specifically 5.0 J / g or less.

[0091] (Configuration of the heat-fused article) In the heat-fused article according to the second embodiment, the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric minus the heat of fusion of the endothermic peak in the DSC curve of the molded article is 2.5 J / g or more. Therefore, when the nonwoven fabric and the molded article are heat-fused together, the molded article melts more easily than the nonwoven fabric, and the molten material of the molded article penetrates into the gaps in the nonwoven fabric, thereby sufficiently heat-fusing the nonwoven fabric and the molded article. Furthermore, when the nonwoven fabric and the molded article are heat-fusing together, the nonwoven fabric melts less easily than the molded article, so the crystallinity of the nonwoven fabric is less likely to decrease, and the strength of the nonwoven fabric at the welding interface is more easily maintained. As a result, the heat-fused article according to the second embodiment has excellent heat-fusing properties between the nonwoven fabric and the molded article.

[0092] As shown in FIG. 1 , the heat-sealed body according to the second embodiment may be a container 10 including a container body 11 having an opening 11a and a lid 12 closing the opening 11a. The container body 11 is the molded body, and the lid 12 includes the nonwoven fabric. The nonwoven fabric and the molded body are heat-sealed at the opening 11a. The container body 11 has an internal space 11b. The container body 11 includes a bottom wall 11c and a cylindrical side wall 11d extending upward from the outer peripheral edge of the upper surface of the bottom wall 11c. The bottom wall 11c has a circular shape in a plan view. That is, the bottom wall 11c is a circular plate. The side wall 11d is formed in a cylindrical shape.

[0093] The lid 12 may be formed of two or more laminated layers. For example, the lid 12 may be formed by heat-sealing the nonwoven fabric and a nonwoven fabric containing cellulose-based fibers. The lid 12 has a circular shape in a plan view.

[0094] Examples of the cellulosic fibers include cotton fibers, rayon (a concept that also includes cupra (also known as "cuprammonium rayon")), and acetate fibers. The lid body is a heat-sealed body with high particle collection efficiency due to the nonwoven fabric containing poly(3-hydroxyalkanoate) resin, and the strength of the lid body is further increased due to the nonwoven fabric containing cellulosic fibers. Examples of the nonwoven fabric containing cellulosic fibers include spunlace nonwoven fabric.

[0095] When a nonwoven fabric containing a poly(3-hydroxyalkanoate) resin and a nonwoven fabric containing cellulosic fibers are heat-sealed together, the nonwoven fabric containing the poly(3-hydroxyalkanoate) resin melts due to the heat.

[0096] In the heat-sealed article according to the second embodiment, the nonwoven fabric containing the poly(3-hydroxyalkanoate) resin and the nonwoven fabric containing the cellulose fiber may be directly fused together. Furthermore, in the heat-sealed article according to the second embodiment, the nonwoven fabric containing the poly(3-hydroxyalkanoate) resin and the nonwoven fabric containing the cellulose fiber may be fused together via another layer, for example, via a film layer formed of a film. Examples of materials constituting the film include polybutylene adipate.

[0097] The heat-sealed article according to the second embodiment can be suitably used for, for example, coffee capsules.

[0098] <Coffee Capsule> The coffee capsule according to this embodiment has the heat-sealed body according to the second embodiment. The heat-sealed body is a container 10 including a container body 11 having an opening 11a and a lid 12 that closes the opening 11a. The container body 11 is the molded body, and the lid 12 includes the nonwoven fabric. The nonwoven fabric and the molded body are heat-sealed at the opening 11a. The container body 11 has an internal space 11b. The coffee capsule according to this embodiment contains coffee powder 13 in the internal space 11b.

[0099] <Method for Producing Nonwoven Fabric> The method for producing a nonwoven fabric according to this embodiment uses a nozzle having nozzle holes to produce a nonwoven fabric containing fibers. The method for producing a nonwoven fabric according to this embodiment includes a step (A) of obtaining a raw yarn by discharging a molten material from the nozzle holes, and a step (B) of stretching the raw yarn by blowing a gas onto the raw yarn. The molten material contains a poly(3-hydroxyalkanoate)-based resin. The poly(3-hydroxyalkanoate)-based resin contains 3-hydroxybutyrate units. The content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate)-based resin contained in the molten material is 91.0 mol% or more and 97.0 mol% or less. In the step (B), the flow rate of the gas blown onto the raw yarn is preferably 900 NL / min / 600 mm or more.

[0100] The method for producing a nonwoven fabric according to this embodiment will be described first using a meltblown method as an example. The meltblown method includes the spunblown (registered trademark) method.

[0101] The melt is obtained from a first raw material composition. In the step (A), the first raw material composition is melted by heating to obtain a melt, and the melt is discharged from the nozzle hole to obtain a raw yarn.

[0102] The melt mass flow rate (MFR) of the first raw material composition at 165°C is preferably 30 to 1500 g / 10 min, more preferably 30 to 1000 g / 10 min, still more preferably 50 to 1000 g / 10 min, and particularly preferably 50 to 800 g / 10 min.

[0103] When the melt mass flow rate of the first raw material composition at 165°C is 1500 g / 10 min or less, the strength and elongation of the nonwoven fabric are further increased. When the melt mass flow rate of the first raw material composition at 165°C is 30 g / 10 min or more, the tension applied to the fibrous molten material during stretching can be reduced, making it easier to reduce the fiber diameter of the fibers in the resulting nonwoven fabric.

[0104] The melt mass-flow rate (MFR) of the first raw material composition at 165°C is determined by ASTM-D1238 (ISO1133-1, JIS K7210-1:2011) Method B, and then determined from the melt volume-flow rate (MVR) of the first raw material composition at 165°C and the density of the first raw material composition. The melt volume-flow rate (MVR) of the first raw material composition at 165°C is measured by heating 5 g or more of the first raw material composition at 165°C for 4 minutes, and then applying a load of 5 kg to the heated raw material composition.

[0105] The weight average molecular weight of the first raw material composition is preferably 100,000 to 350,000, more preferably 110,000 to 300,000, and even more preferably 110,000 to 250,000.

[0106] When the weight-average molecular weight of the first raw material composition is 100,000 or more, the strength and elongation of the nonwoven fabric are further increased. When the weight-average molecular weight of the first raw material composition is 350,000 or less, the tension applied to the fibrous molten material during stretching can be reduced, making it easier to reduce the fiber diameter of the fibers in the resulting nonwoven fabric.

[0107] In the method for producing a nonwoven fabric according to this embodiment, a nonwoven fabric is obtained from the first raw material composition using a nonwoven fabric production apparatus.

[0108] As shown in FIG. 2 , the nonwoven fabric manufacturing apparatus 1 includes an extruder 3 that melts a first raw material composition to obtain a melt, a hopper 2 that supplies the first raw material composition to the extruder 3, a kneader 6 that kneads the melt to obtain a kneaded melt (hereinafter also referred to as a “kneaded melt”), a nozzle 7 that discharges the molten kneaded material in a fibrous form, a collector 8 that collects and cools the fibrous molten kneaded material to obtain a first nonwoven fabric B, and a winding device 9 that winds up the first nonwoven fabric B.

[0109] Furthermore, the nonwoven fabric manufacturing apparatus 1 may, if necessary, include a gear pump 4 that supplies the molten material to the kneader 6. By including the gear pump 4, the nonwoven fabric manufacturing apparatus 1 can suppress fluctuations in the amount of molten material supplied to the kneader 6.

[0110] Furthermore, the nonwoven fabric manufacturing apparatus 1 may be provided with a filter 5 upstream of the kneader 6 for removing foreign matter from the molten material, if necessary.

[0111] In the step (A), a first raw material composition is supplied to an extruder 3 via a hopper 2, and the raw material composition is melted to obtain a melt.

[0112] The first raw material composition supplied to the extruder 3 is preferably in a solid state, more preferably in a pellet state. The first raw material composition supplied to the extruder 3 is preferably dried by heating, from the viewpoint of suppressing hydrolysis of the resin in the first raw material composition and suppressing oxidative degradation of the resin in the first raw material composition. The moisture content of the first raw material composition supplied to the extruder 3 is preferably 200 ppmw or less. When drying the first raw material composition, it is preferable to remove oxygen from the atmosphere or to remove oxygen from the first raw material composition. The drying atmosphere is preferably an inert gas atmosphere (e.g., nitrogen gas). In the step (A), the first raw material composition may be dried before being supplied to the hopper 2. Alternatively, the hopper 2 may be a hopper-type dryer, and the first raw material composition may be dried in the hopper 2.

[0113] Examples of the extruder 3 include a single-screw extruder, a co-rotating intermeshing twin-screw extruder, a co-rotating non-intermeshing twin-screw extruder, a counter-rotating non-intermeshing twin-screw extruder, a multi-screw extruder, etc. As the extruder 3, a single-screw extruder is preferred from the viewpoint that thermal degradation of the first raw material composition during extrusion is easily suppressed due to a small resin retention area in the extruder, and from the viewpoint that equipment costs are low.

[0114] In the step (A), the melt is supplied to a kneader 6 via a filter 5 by a gear pump 4, and the melt is kneaded in the kneader 6 to obtain a kneaded melt.

[0115] Examples of the filter 5 include a screen mesh, a pleated filter, and a leaf disc filter. From the viewpoints of filtration accuracy, filtration area, and pressure resistance, as well as the fact that clogging due to foreign matter is unlikely to occur, a leaf disc filter is preferred as the filter 5. As the filter material of the filter 5, for example, a sintered nonwoven fabric of metal fibers can be used.

[0116] In the step (A), the melted and kneaded material is discharged from the nozzle 7 in the form of fibers.

[0117] The nozzle 7 is a spinning die head. In Fig. 3, the nozzle 7 has a plurality of nozzle holes 7a that discharge the molten kneaded material in a fibrous form. As shown in Fig. 3, the nozzle 7 discharges a plurality of fibrous molten kneaded materials A. Note that the nozzle 7 may have only one nozzle hole 7a. In other words, the nozzle 7 may discharge only one raw yarn A.

[0118] The plurality of nozzle holes 7a open downward. The shape of the nozzle holes 7a is, for example, circular (a concept including circular, approximately circular, elliptical, and approximately elliptical). The diameter of the nozzle holes 7a is appropriately selected depending on the fiber diameter of the fibers of the nonwoven fabric. The diameter of the nozzle holes 7a is preferably 0.05 mm or more, more preferably 0.10 mm or more, and even more preferably 0.12 mm or more. The diameter of the nozzle holes 7a is preferably 1.0 mm or less, more preferably 0.50 mm or less, even more preferably less than 0.30 mm, and particularly preferably 0.25 mm or less. The opening diameter refers to the arithmetic mean value of the opening diameters.

[0119] The ratio of the opening area of ​​the nozzle hole to the cross-sectional area of ​​the fiber is preferably 900 or more, more preferably 2,000 to 20,000, and even more preferably 3,000 to 15,000. The ratio of the opening area of ​​the nozzle hole to the cross-sectional area of ​​the fiber serves as an index of the draw ratio.

[0120] When the ratio of the opening area of ​​the nozzle hole to the cross-sectional area of ​​the fiber is 900 or more, the obtained nonwoven fabric has a high heat of fusion at the endothermic peak in the DSC curve. As a result, the nonwoven fabric has excellent heat-fusion properties with other materials (e.g., nonwoven fabrics containing cellulose-based fibers, molded articles containing poly(3-hydroxyalkanoate)-based resins, etc.). Furthermore, when the ratio of the opening area of ​​the nozzle hole to the cross-sectional area of ​​the fiber is 2,000 or more, the fibers are sufficiently stretched and crystallized. As a result, the meltblown nonwoven fabric has even better heat-fusion properties with other materials (e.g., nonwoven fabrics containing cellulose-based fibers, molded articles containing poly(3-hydroxyalkanoate)-based resins, etc.).

[0121] The cross-sectional area of ​​the fiber can be determined from the average fiber diameter of the fiber, assuming that the cross section of the fiber is circular.

[0122] The opening area of ​​the nozzle hole means the average value of the opening areas of the nozzle holes. When the openings are circular, the opening area of ​​the nozzle hole can be calculated from the arithmetic average value of the opening diameters.

[0123] In the nozzle 7, a plurality of nozzle holes 7a are arranged in a row with a gap therebetween. In FIG. 3, the plurality of nozzle holes 7a are arranged in a single row. The plurality of nozzle holes 7a may be arranged in two or more rows. In other words, the meltblown method may be a spunblown (registered trademark) method. The distance between adjacent nozzle holes 7a (hereinafter also referred to as "spacing") is, for example, preferably 0.05 mm or more, more preferably 0.10 mm or more, and even more preferably 0.20 mm or more. By having the distance (spacing) between adjacent nozzle holes 7a be 0.05 mm or more, fusion of adjacent fibers can be suppressed, and as a result, the coefficient of variation of the fiber diameter of the fibers can be reduced. Furthermore, the distance (spacing) between adjacent nozzle holes 7a is, for example, preferably 1.0 mm or less, more preferably 0.7 mm or less, and even more preferably 0.5 mm or less. The distance between adjacent nozzle holes 7a may or may not be uniform, but uniformity is preferable in terms of facilitating the production of a homogeneous nonwoven fabric. The distance (interval) between adjacent nozzle holes 7a means the arithmetic mean value of the distance (interval) between adjacent nozzle holes 7a.

[0124] The collector 8 has a collecting surface that collects the fibrous kneaded material A. The collector 8 is a conveyor. The conveyor includes a conveyor belt 8a having the collecting surface and a plurality of rollers 8b that drive the conveyor belt 8a. The collecting surface is disposed directly below the nozzle holes 7a. The conveyor belt 8a is breathable. Specifically, the conveyor belt 8a is formed of a mesh-like material. That is, the collecting surface is mesh-like. The collector 8 only needs to have a collecting unit, and may be a collecting drum or a collecting net instead of the conveyor.

[0125] The distance (DCD) between the nozzle hole 7a and the collecting surface is preferably 20 mm or more, more preferably 50 mm or more, and even more preferably 80 mm or more. The distance (DCD) between the nozzle hole 7a and the conveyor belt 8a serving as the collecting section is preferably 250 mm or less. The distance (DCD) between the nozzle hole 7a and the collecting surface refers to the arithmetic mean value of the distance (DCD) between the nozzle hole 7a and the collecting surface.

[0126] As shown in FIG. 4, the nonwoven fabric manufacturing apparatus 1 is configured to stretch the fibrous melt-kneaded material A by blowing a high-temperature gas C onto the fibrous melt-kneaded material A.

[0127] In the step (B), a high-temperature gas C is blown onto the fibrous melt-kneaded material A, and the high-temperature gas C blown onto the melt-kneaded material A is passed through a mesh conveyor belt 8a. In the step (B), the high-temperature gas C is preferably sucked by suction (not shown) so that the high-temperature gas C blown onto the melt-kneaded material A can easily pass through the mesh conveyor belt 8a. This makes it easier to prevent the fibers from bouncing off the collection surface of the mesh conveyor belt 8a, and as a result, it becomes easier to form a first nonwoven fabric B in which the fibers are well fused together.

[0128] In the step (B), the stretched fibrous melt-kneaded product A is collected by the conveyor belt 8a and cooled while being conveyed by the conveyor belt 8a, thereby obtaining a first nonwoven fabric.

[0129] The material constituting the mesh-like collection surface is not particularly limited as long as it has heat resistance to the temperature conditions involved in the production of the first nonwoven fabric B, does not excessively fuse with the first nonwoven fabric B, and is a material from which the first nonwoven fabric B can be peeled off.

[0130] Examples of the gas C include air and inert gases (nitrogen gas, etc.). Examples of a method for blowing high-temperature gas C include a method in which gas C pressurized by a compressor (not shown) is heated by a heater (not shown).

[0131] The flow rate of the high-temperature gas C blown onto the fibrous melt-kneaded material A is preferably 900 NL / min / 600 mm or more, more preferably 3000 NL / min / 600 mm or more, and even more preferably 4000 NL / min / 600 mm or more. The flow rate of the high-temperature gas C blown onto the fibrous melt-kneaded material A is preferably 12000 NL / min / 600 mm or less, more preferably 10000 NL / min / 600 mm or less. The flow rate of the gas C (unit: NL / min / 600 mm) refers to the value obtained by dividing the total flow rate of the gas C (unit: NL / min) by the length (width) of the nozzle 7 in the CD direction, with the units adjusted accordingly. The length (width) of the nozzle 7 in the CD direction refers to the length (width) (mm) of the gas C in the CD direction.

[0132] By setting the flow rate of gas C to 900 NL / min / 600 mm or more, the resulting nonwoven fabric has a high heat of fusion at the endothermic peak in the DSC curve. As a result, the nonwoven fabric has excellent heat-sealing properties with other materials (e.g., nonwoven fabrics containing cellulose-based fibers, molded articles containing poly(3-hydroxyalkanoate)-based resins, etc.). Furthermore, by setting the flow rate of gas C to 3000 NL / min / 600 mm or more, the fibers are sufficiently stretched and crystallized. As a result, the nonwoven fabric has even better heat-sealing properties with other materials (e.g., nonwoven fabrics containing cellulose-based fibers, molded articles containing poly(3-hydroxyalkanoate)-based resins, etc.).

[0133] In the step (B), the temperature and flow rate of the high-temperature gas C are appropriately controlled in order to obtain a nonwoven fabric with a high degree of crystallinity.

[0134] The speed at which the first nonwoven fabric B is moved by the conveyor belt 8a (the speed of the conveyor belt 8a) is appropriately determined taking into consideration the discharge amount of the first raw material composition and the apparent density of the resulting first nonwoven fabric B. The speed is preferably in the range of 1.0 m / min to 6.0 m / min.

[0135] In the step (B), the first nonwoven fabric B is transported by the conveyor belt 8a to the winding device 9, and the first nonwoven fabric B is wound up in a roll by the winding device 9.

[0136] The method for producing a nonwoven fabric according to this embodiment may include a step (C) of heating the first nonwoven fabric B obtained in the step (B) to obtain a second nonwoven fabric.

[0137] When the method for producing a nonwoven fabric according to this embodiment includes the step (C), the second nonwoven fabric is the nonwoven fabric. On the other hand, when the method for producing a nonwoven fabric according to this embodiment does not include the step (C), the first nonwoven fabric is the nonwoven fabric.

[0138] In the method for producing a nonwoven fabric according to this embodiment, the step (C) makes the nonwoven fabric less likely to tear. Furthermore, in the method for producing a nonwoven fabric according to this embodiment, the step (C) can increase the tensile elongation at break in the CD direction and the tensile elongation at break in the MD direction of the nonwoven fabric. Furthermore, in the method for producing a nonwoven fabric according to this embodiment, the step (C) partially fuses the fibers together, which makes it easier to suppress fuzzing of the nonwoven fabric.

[0139] The heating temperature range in step (C) is preferably 80°C to 135°C. The heating time within the preferred heating temperature range in step (C) is preferably 2 to 300 minutes, more preferably 5 to 100 minutes, and even more preferably 10 to 50 minutes. In step (C), by heating the first nonwoven fabric for 2 minutes or more within the preferred heating temperature range, the tensile elongation at break in the CD direction and the tensile elongation at break in the MD direction of the nonwoven fabric can be further increased. Furthermore, in step (C), by heating the first nonwoven fabric for 300 minutes or less within the preferred heating temperature range, the productivity of the second nonwoven fabric is improved.

[0140] In step (C), the first nonwoven fabric may be heated with a gas within the preferred heating temperature range. Examples of the gas include air and inert gas (nitrogen gas, etc.). Examples of a method for heating the first nonwoven fabric with a gas within the preferred heating temperature range include heating the first nonwoven fabric in a heating furnace with a gas within the preferred heating temperature range and / or heating the first nonwoven fabric by blowing a gas within the preferred heating temperature range onto the first nonwoven fabric.

[0141] In the step (C), the first nonwoven fabric may be sandwiched between a pair of heating rolls to heat the first nonwoven fabric within the preferable heating temperature range.

[0142] In the step (C), it is preferable to heat the first nonwoven fabric without contact within the preferred heating temperature range. In the step (C), if the first nonwoven fabric is heated by being sandwiched between a pair of heating rolls, there is a concern that the first nonwoven fabric may fuse to the heating rolls. In the step (C), by heating the first nonwoven fabric within the preferred heating temperature range without contact with the heating rolls or the like, there is an advantage that it is possible to prevent the first nonwoven fabric from fusing to the heating rolls or the like. Examples of a method for heating the first nonwoven fabric without contact within the preferred heating temperature range include a method of heating the first nonwoven fabric with a gas within the preferred heating temperature range.

[0143] In the step (C), the first nonwoven fabric may be heated in a state where the first nonwoven fabric is wound into a roll.

[0144] In the step (C), the first nonwoven fabric may be formed into a sheet without being wound around a roll, and then heated. For example, the first nonwoven fabric in a long shape may be continuously heated while being transported.

[0145] In step (C), the heated first nonwoven fabric is cooled to obtain a second nonwoven fabric. The method for cooling the heated first nonwoven fabric may be a method of naturally cooling the heated first nonwoven fabric at room temperature and normal pressure, or a method of forcibly cooling the heated first nonwoven fabric by blowing gas (e.g., gas at room temperature) onto the heated first nonwoven fabric.

[0146] In the method for producing the nonwoven fabric, the nonwoven fabric may be produced by a spunbond method, a flash spinning method, or an electrospinning method. In the method for producing the nonwoven fabric, the nonwoven fabric is preferably produced by a meltblown method or a spunbond method.

[0147] In the spunbonding method, the first raw material composition is heated to melt the melt, and the melt is discharged through the nozzle hole to obtain the raw yarn. Next, room temperature gas is blown onto the raw yarn to stretch the raw yarn. In the spunbonding method, the ratio of the nozzle hole opening area to the cross-sectional area of ​​the fiber can be increased by increasing the volume of gas blown onto the raw yarn. The ratio of the nozzle hole opening area to the cross-sectional area of ​​the fiber can also be increased by decreasing the amount of melt discharged through the nozzle hole per unit time. In the spunbonding method, the raw yarn may be drawn using a drawing roll. In this case, the ratio of the nozzle hole opening area to the cross-sectional area of ​​the fiber can be increased by increasing the rotation speed of the drawing roll. The ratio of the nozzle hole opening area to the cross-sectional area of ​​the fiber can also be increased by decreasing the amount of melt discharged through the nozzle hole per unit time.

[0148] In the flash spinning method, the materials of the first raw material composition and a solvent are mixed under high temperature and pressure to obtain a melt under high temperature and pressure. Next, the melt under high temperature and pressure is discharged from the nozzle hole under normal temperature and pressure to obtain the raw yarn, and the obtained raw yarn is stretched. Examples of the solvent include alcohol (e.g., methanol, ethanol, etc.) and acetone. In the flash spinning method, the ratio of the opening area of ​​the nozzle hole to the cross-sectional area of ​​the fiber can be increased by increasing the pressure applied to the melt. In addition, the ratio of the opening area of ​​the nozzle hole to the cross-sectional area of ​​the fiber can also be increased by decreasing the amount of melt discharged from the nozzle hole per unit time.

[0149] In the electrospinning method, the first raw material composition is heated and melted by irradiating it with laser light while a high voltage is applied. As a result, the molten material can be obtained. Next, the molten material is discharged from the nozzle hole to obtain a raw yarn. The raw yarn is then stretched by electrostatic force. In the electrospinning method, the ratio of the opening area of ​​the nozzle hole to the cross-sectional area of ​​the fiber can be increased by increasing the electrostatic force. In addition, the ratio of the opening area of ​​the nozzle hole to the cross-sectional area of ​​the fiber can also be increased by decreasing the amount of molten material discharged from the nozzle hole per unit time.

[0150] <Method for producing a heat-fused article according to the first embodiment> The method for producing a heat-fused article according to the first embodiment is a method for obtaining a heat-fused article by heat-fusing the nonwoven fabric according to this embodiment with a nonwoven fabric containing cellulosic fibers.

[0151] <Method for manufacturing a heat-fused article according to a second embodiment> The method for manufacturing a heat-fused article according to a second embodiment is a method for obtaining a heat-fused article by heat-fusing a nonwoven fabric containing fibers with a molded article. The fibers are formed from a first resin composition containing a poly(3-hydroxyalkanoate)-based resin. The molded article is formed from a second resin composition containing a poly(3-hydroxyalkanoate)-based resin. The value obtained by subtracting the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric from the heat of fusion of the endothermic peak in the DSC curve of the molded article is 2.5 J / g or more. The nonwoven fabric is the nonwoven fabric according to this embodiment.

[0152] In the method for producing a heat-sealed body according to the second embodiment, the heat-sealing can be carried out by irradiating the area to be heat-sealed with ultrasonic waves.

[0153] The heating temperature in the heat fusion is preferably (the melting point of the molded body + 5°C) or higher (the thermal decomposition temperature of the molded body - 5)°C or lower. When the heating temperature in the heat fusion is (the melting point of the molded body + 5°C) or higher, the nonwoven fabric and the molded body are more likely to be thermally welded together more sufficiently. When the heating temperature in the heat fusion is (the thermal decomposition temperature of the molded body - 5)°C or lower, the molded body is less likely to be thermally decomposed.

[0154] The thermal decomposition temperature of the molded body is the onset temperature determined according to the method described in JIS K 71201-1987 "Thermogravimetric measurement method for plastics." When multi-stage mass loss occurs, the first onset temperature is taken as the thermal decomposition temperature of the molded body.

[0155] (Method for producing molded body) In the method for producing the molded body, the materials constituting the second raw material composition are melt-kneaded, and if necessary, pellets are obtained, and then the molded body can be produced by known injection molding.

[0156] In the method for producing a molded article, first, the materials constituting the second raw material composition are melt-kneaded using an extruder, kneader, Banbury mixer, roll, or the like to obtain a melt-kneaded product. Next, the melt-kneaded product is extruded into a strand shape and then cut to obtain pellets having a particle shape (e.g., cylindrical, elliptical, spherical, cubic, rectangular, etc.). The produced pellets are preferably thoroughly dried at 40 to 80°C to remove moisture, and then subjected to injection molding.

[0157] The temperature at which the melt-kneading is carried out cannot be generally defined because it depends on the melting point, melt viscosity, etc. of the resin used, but the resin temperature of the melt-kneaded product at the die outlet is preferably 140 to 190°C, more preferably 145 to 185°C, and even more preferably 150 to 180°C. By keeping the resin temperature of the melt-kneaded product at 140°C or higher, the polymer components including the poly(3-hydroxyalkanoate) resin can be sufficiently melted. Furthermore, by keeping the resin temperature of the melt-kneaded product at 190°C or lower, thermal decomposition of the polymer components including the poly(3-hydroxyalkanoate) resin can be suppressed.

[0158] The produced pellets are then subjected to injection molding to form the molded article. Injection molding is a method in which a heated and melted second raw material composition is injected into a mold, the second raw material composition is cooled and solidified in the mold, the mold is opened, and the molded article is demolded to obtain a molded article. In addition to injection molding methods commonly used when molding thermoplastic resins, gas-assisted molding, injection compression molding, injection blow molding (including one-step and two-step), and the like can also be used. In-mold molding, gas press molding, two-color molding, sandwich molding, push-pull molding, SCORIM molding, and the like can also be used. However, usable injection molding methods are not limited to the above methods.

[0159] The temperature at which the mixture is cooled in the mold after injection is, for example, preferably 20 to 70°C, more preferably 25 to 60°C, even more preferably 30 to 50°C, and particularly preferably 35 to 45°C.

[0160] Disclosure Items Each of the following items is a disclosure of a preferred embodiment.

[0161] [Item 1] A nonwoven fabric comprising fibers, wherein the fibers are formed from a resin composition containing a poly(3-hydroxyalkanoate)-based resin, the poly(3-hydroxyalkanoate)-based resin contains 3-hydroxybutyrate units, the content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate)-based resin contained in the nonwoven fabric is 91.0 mol % or more and 97.0 mol % or less, and the heat of fusion of an endothermic peak in a DSC curve of the nonwoven fabric is 50.0 J / g or more.

[0162] [Item 2] The nonwoven fabric according to item 1, wherein the nonwoven fabric is a meltblown nonwoven fabric.

[0163] [Item 3] The meltblown nonwoven fabric according to item 1 or 2, wherein the average fiber diameter of the fibers is 3.3 μm or more.

[0164] [Item 4] The nonwoven fabric according to any one of Items 1 to 3, wherein the maximum load in the MD direction of the nonwoven fabric is 0.7 N or more, and the maximum load in the CD direction of the nonwoven fabric is 0.7 N or more.

[0165] [Item 5] A heat-fused article obtained by heat-fusing the nonwoven fabric according to any one of items 1 to 4 with a nonwoven fabric containing cellulosic fibers.

[0166] [Item 6] A coffee filter formed from the heat-sealed product according to item 5.

[0167] [Item 7] A heat-fused article obtained by heat-fusing a nonwoven fabric containing fibers and a molded article, wherein the fibers are formed from a first resin composition containing a poly(3-hydroxyalkanoate)-based resin, and the molded article is formed from a second resin composition containing a poly(3-hydroxyalkanoate)-based resin, and the value obtained by subtracting the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric from the heat of fusion of the endothermic peak in the DSC curve of the molded article is 2.5 J / g or more, and the nonwoven fabric is the nonwoven fabric according to any one of Items 1 to 4.

[0168] [Item 8] The heat-sealed article according to Item 7, wherein the second resin composition contains a poly(3-hydroxyalkanoate) resin containing a 3-hydroxybutyrate unit.

[0169] [Item 9] The heat-fused article according to Item 8, wherein the content of the 3-hydroxybutyrate unit in the poly(3-hydroxyalkanoate) resin contained in the second resin composition is 91.0 mol% or more and 97.0 mol% or less.

[0170] [Item 10] The heat-sealed product according to any one of Items 7 to 9, which is a container comprising a container body having an opening and a lid that closes the opening, wherein the container body is the molded body, the lid has the nonwoven fabric, and the nonwoven fabric and the molded body are heat-sealed at the opening.

[0171] [Item 11] A coffee capsule having the heat-sealable body according to item 10, wherein the container body has an internal space, and coffee powder is contained in the internal space.

[0172] [Item 12] A method for producing a heat-fused article, comprising heat-fusing a nonwoven fabric containing fibers to a molded article to obtain a heat-fused article, wherein the fibers are formed from a first resin composition containing a poly(3-hydroxyalkanoate)-based resin, and the molded article is formed from a second resin composition containing a poly(3-hydroxyalkanoate)-based resin, and the value obtained by subtracting the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric from the heat of fusion of the endothermic peak in the DSC curve of the molded article is 2.5 J / g or more, and the nonwoven fabric is the nonwoven fabric according to any one of claims 1 to 4.

[0173] [Item 13] The method for producing a heat-fused body according to Item 12, wherein the heating temperature in the heat fusion is (the melting point of the molded body + 5)°C or higher and (the thermal decomposition temperature of the molded body - 5)°C or lower.

[0174] [Item 14] A method for producing a meltblown nonwoven fabric using a nozzle having nozzle holes to produce a meltblown nonwoven fabric containing fibers, the method comprising: step (A) of obtaining a raw yarn by discharging a molten material from the nozzle holes; and step (B) of stretching the raw yarn by blowing a gas onto the raw yarn, wherein the molten material contains a poly(3-hydroxyalkanoate)-based resin, the poly(3-hydroxyalkanoate)-based resin contains 3-hydroxybutyrate units, the content of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate)-based resin contained in the molten material is 91.0 mol% or more and 97.0 mol% or less, and in step (B), the flow rate of the gas blown onto the raw yarn is 900 NL / min / 600 mm or more.

[0175] [Item 15] The method for producing a meltblown nonwoven fabric according to Item 14, wherein the ratio of the opening area of ​​the nozzle holes to the cross-sectional area of ​​the fibers is 900 or more.

[0176] It should be noted that the present invention is not limited to the above-described embodiment. Furthermore, the present invention is not limited to the above-described effects. Furthermore, the present invention can be modified in various ways without departing from the spirit of the present invention.

[0177] Next, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples in any way.

[0178] The following materials were prepared.

[0179] (Poly(3-hydroxyalkanoate)-based resin (P3HA)) The following P3HA was prepared according to the method described in Example 1 of WO 2019 / 142845. P3HA-1: P3HB3HH (content of 3-hydroxybutyrate units: 94.5 mol%, content of 3-hydroxyhexanoate (3HH) units: 5.5 mol%). PHA-F described in Table 1 of WO 2022 / 065181 was also prepared. P3HA-2: P3HB3HH (content of 3-hydroxybutyrate units: 94.0 mol%, content of 3-hydroxyhexanoate (3HH) units: 6.0 mol%)

[0180] The 3-hydroxybutyrate unit content and 3-hydroxyhexanoate (3HH) unit content in P3HA were determined as follows. First, 20 mg of dried P3HA was added with 2 mL of a mixture of sulfuric acid and methanol (sulfuric acid volume:methanol volume=15:85) and 2 mL of chloroform. The resulting sample was sealed and heated at 100°C for 140 minutes in a sealed state to obtain a first reaction solution containing methyl esters, which are decomposition products of P3HA. The first reaction solution was then cooled, and 1.5 g of sodium bicarbonate was added little by little to neutralize the cooled first reaction solution. The mixture was then left to stand until carbon dioxide generation ceased, to obtain a second reaction solution. The second reaction solution was then thoroughly mixed with 4 mL of diisopropyl ether to obtain a mixture. The mixture was then centrifuged to obtain a supernatant. The monomer unit composition of the decomposition product in the supernatant was then analyzed by capillary gas chromatography under the following conditions to determine the content of 3-hydroxybutyrate units and 3-hydroxyhexanoate (3HH) units in P3HA. Gas chromatograph: GC-17A manufactured by Shimadzu Corporation. Capillary column: NEUTRA BOND-1 manufactured by GL Sciences (column length: 25 m, column inner diameter: 0.25 mm, liquid film thickness: 0.4 μm). Carrier gas: He. Column inlet pressure: 100 kPa. Sample volume: 1 μL. Regarding temperature conditions, the temperature was increased at a rate of 8°C / min from 100 to 200°C, and then at a rate of 30°C / min from 200 to 290°C.

[0181] (Lubricant) BA: behenic acid amide (also called "behenic acid amide") (manufactured by Nippon Fine Chemicals Co., Ltd., BNT-22H) EA: erucic acid amide (manufactured by Nippon Fine Chemicals Co., Ltd., Neutron S)

[0182] (Nucleating Agent) PETL: Pentaerythritol (manufactured by Taisei Kayaku Co., Ltd., Neuraizer P)

[0183] (First raw material composition) The above materials were melt-kneaded in the blending ratios shown in Table 1 below to obtain a first raw material composition. The weight average molecular weight (Mw) and melt mass flow rate (MFR) at 165°C of the first raw material composition were adjusted by utilizing shear heat generated by the melt-kneading.

[0184] (Measurement of physical properties of first raw material composition) The weight average molecular weight (Mw) and melt mass flow rate (MFR) at 165°C of the first raw material composition were measured. The measured values ​​are shown in Table 1 below. The weight average molecular weight (Mw) of the first raw material composition was calculated by GPC measurement. The conditions for the GPC measurement are shown below. Measuring apparatus: Shimadzu 20A manufactured by Shimadzu Corporation Column: Shodex K-806M manufactured by Showa Denko Detector: RI detector Standard material: polystyrene Eluent: chloroform (HPLC grade) Flow rate: 1 mL / min Temperature: 40°C

[0185]

[0186] (Nonwoven fabrics of Examples 1 to 5 and Comparative Example 1) Using the nonwoven fabric manufacturing apparatus shown in Figures 2 to 4, nonwoven fabrics were manufactured from the first raw material composition by the meltblown method under the conditions shown in Table 2. A nozzle with a length (width) of 600 mm in the CD direction was used to manufacture the nonwoven fabric.

[0187]

[0188] (Measurement of Physical Properties of Nonwoven Fabric) For the nonwoven fabric, the basis weight, thickness, average fiber diameter of the fibers, coefficient of variation of fiber diameter of the fibers, heat of fusion of the endothermic peak in the DSC curve, and weight average molecular weight of the first resin composition were measured using the methods described above. The measured values ​​are shown in Table 3 below. The average fiber diameter of the fibers and the coefficient of variation of fiber diameter of the fibers were determined using a JEOL JCM-6000 tabletop scanning electron microscope. The conditions for GPC measurement of the weight average molecular weight of the first resin composition were the same as those for GPC measurement of the weight average molecular weight (Mw) of the first raw material composition. The DSC curve for the nonwoven fabric of Example 2 is shown in FIG. 5.

[0189] (Maximum load, tensile elongation at maximum load, and tensile elongation at break in the CD and MD directions of nonwoven fabric) The maximum load, tensile elongation at maximum load, and tensile elongation at break in the CD and MD directions of the nonwoven fabric were measured. The maximum load, tensile elongation at maximum load, and tensile elongation at break in the CD and MD directions were measured using a constant-rate extension tensile tester in accordance with JIS B7721:2018 "Tensile tester / compression tester - Calibration and verification method for force measurement system." A universal testing machine (RTG-1210 manufactured by A&D Co., Ltd.) or the like was used as the constant-rate extension tensile tester. First, a test specimen (width: 8 mm, length: 40 mm) was cut from the nonwoven fabric. Next, the test specimen was attached to the tensile tester with an initial load and a grip spacing of 20 mm. In other words, the grip spacing when the initial load was applied to the test specimen was 20 mm. However, when the initial load was applied, the test specimen was pulled by hand to a degree that did not cause slack. A load was then applied at a pulling rate of 20 mm / min until the test specimen broke, and the maximum load in the CD and MD directions was measured. The tensile elongation at maximum load in the CD and MD directions and the tensile elongation at break were also calculated using the following formulas: Tensile elongation at maximum load (%) = [(Grip spacing at maximum load - Grip spacing when initial load was applied to the test specimen) / Grip spacing when initial load was applied to the test specimen] x 100 (%) Tensile elongation at break (%) = [(Grip spacing at break - Grip spacing when initial load was applied to the test specimen) / Grip spacing when initial load was applied to the test specimen] x 100 (%) The measured values ​​are shown in Table 3 below.

[0190] (Opening Area of ​​Nozzle Hole / Cross-Sectional Area of ​​Fiber) The opening area of ​​the nozzle hole / cross-sectional area of ​​the fiber was calculated by the method described above.

[0191]

[0192] Nonwoven fabrics containing cellulosic fibers (specifically, rayon fibers) were prepared as shown in Table 4. The physical properties shown in Table 4 were measured using the same methods as those for measuring the physical properties of nonwoven fabrics.

[0193]

[0194] (Evaluation Test (CD Direction)) A first test piece (width: 8 mm, length: 40 mm) was cut out from a nonwoven fabric. The CD direction was the length direction, and the MD direction was the width direction. A second test piece (width: 8 mm, length: 40 mm) was cut out from a nonwoven fabric containing cellulose-based fibers. The CD direction was the length direction, and the MD direction was the width direction. Next, the first test piece and the second test piece were placed together in a folded position, with the CD direction of the first test piece and the CD direction of the second test piece aligned in the same direction. Then, as shown in Figures 6 and 7 , the first test piece 21 and the second test piece 22 were heat-sealed together at 160°C for 3 seconds using a heat sealer, so as to form a fused portion 23 that extended linearly in the MD direction of the first test piece 21 at the center of the CD direction of the first test piece 21. This produced a heat-sealed body 20. Next, the heat-fused specimen was attached to a tensile tester with an initial load and a gripping distance of 20 mm. At one end of the heat-fused specimen, only the first test piece was gripped with a gripper, and at the other end of the heat-fused specimen, only the second test piece was gripped with a gripper. The maximum load, tensile elongation at maximum load, and tensile elongation at break of the heat-fused specimen in the CD direction of the nonwoven fabric were then measured in the same manner as for measuring the maximum load, tensile elongation at maximum load, and tensile elongation at break of the nonwoven fabric. The measured values ​​are shown in Table 5 below. The break positions are also shown in Table 5 below. In Table 5 below, "fused portion" refers to the fused portion of the nonwoven fabric, "nonwoven fabric" refers to the nonwoven fabric, and "fused interface" refers to the fused interface between the meltblown nonwoven fabric and the nonwoven fabric containing cellulosic fibers.

[0195] (Evaluation Test (MD Direction)) A first test piece (width: 8 mm, length: 40 mm) was cut out from a nonwoven fabric. At this time, the MD direction was the length direction and the CD direction was the width direction. A second test piece (width: 8 mm, length: 40 mm) was cut out from a nonwoven fabric containing cellulose-based fibers. At this time, the CD direction was the length direction and the MD direction was the width direction. Next, the first test piece and the second test piece were overlapped in a folded state so that the MD direction of the first test piece and the CD direction of the second test piece were the same direction. Then, using a heat sealer, the first test piece and the second test piece were heat-fused at 160°C for 3 seconds to form a heat-fused portion that extended linearly in the CD direction of the first test piece at the center of the MD direction of the first test piece, thereby producing a heat-fused body. Next, the test pieces were attached to a tensile tester with an initial load and a grip distance of 20 mm. At one end of the heat-fused product, only the first test piece was gripped with a gripper, and at the other end of the heat-fused product, only the second test piece was gripped with a gripper. The maximum load, tensile elongation at maximum load, and tensile elongation at break of the heat-fused product in the MD direction of the nonwoven fabric were then measured in the same manner as for the nonwoven fabric. The measured values ​​are shown in Table 5 below. The break positions are also shown in Table 5 below.

[0196]

[0197] As shown in Table 5, Examples 1 to 5, which are within the scope of the present invention, had larger maximum load values ​​than Comparative Example 1, which had a heat of fusion of 49.8 J / g. Furthermore, Comparative Example 1 broke due to cracking at the fusion interface. Therefore, the present invention can provide a nonwoven fabric that has excellent heat-fusion properties with other materials, such as nonwoven fabrics containing cellulosic fibers.

[0198] (Molded Article) A pellet-shaped second raw material composition was prepared, containing 98% or more of the P3HA-2, where the P3HA was the P3HA-2. The pellet-shaped second raw material composition was then dried at 60°C for 24 hours using a dehumidifying dryer. A molded article was then prepared from the dried pellet-shaped second raw material composition by injection molding. The molded article was a container body with an opening. For the injection molding, a Toyo Machinery & Metals Si-30V injection molding machine was used, and the barrel temperatures of the injection molding machine were set to nozzle / T1 / T2 / T3 = 155°C / 145°C / 135°C / 125°C, the mold temperature was set to 35°C, and the injection speed was 20 mm / sec. The heat of fusion at the endothermic peak in the DSC curve of the molded article, the melting point of the molded article, and the thermal decomposition temperature of the molded article were measured using the methods described above. The DSC curve of the molded article is shown in Figure 8. The heat of fusion of the endothermic peak in the DSC curve of the molded body was 47.4 J / g, the melting point of the molded body was 145° C., and the thermal decomposition temperature of the molded body was 185° C. or higher.

[0199] (Heat-fused body) The nonwoven fabrics of Examples 1 to 5 and Comparative Example 1 were used as lids, and the lids and the container bodies were heat-fused at the openings of the container bodies using ultrasound at 150°C to 180°C so as to close the openings of the container bodies with the lids, to produce heat-fused bodies. Table 6 below shows the value obtained by subtracting the heat of fusion of the endothermic peak in the DSC curve of the molded body from the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric for each heat-fused body (hereinafter also simply referred to as the "difference in heat of fusion").

[0200] (Evaluation of Heat-Sealing Properties) For the heat-sealed articles of Examples 1 to 5 and Comparative Example 1, the vicinity of the fused interface was pressed with a finger, and the resistance to tearing of the fused interface was evaluated according to the following criteria. ×: The fused interface easily broke when pressed with a finger near the fused interface. ◯: The fused interface did not easily break when pressed with a finger near the fused interface, but when pressed more firmly with a finger near the fused interface, the fused interface broke. ⊚: The fused interface did not break even when pressed firmly with a finger near the fused interface. The results are shown in Table 6 below.

[0201]

[0202] As shown in Table 6, in Examples 1 to 5, which are within the scope of the present invention, the heat-sealing properties were evaluated as ⊚ or ◯. On the other hand, the heat-sealing properties were evaluated as x in Comparative Example 1. Therefore, according to the present invention, a nonwoven fabric having excellent heat-sealing properties with other materials, such as molded articles containing a poly(3-hydroxyalkanoate) resin, can be provided.

[0203] 1: Nonwoven fabric manufacturing apparatus, 2: Hopper, 3: Extruder, 4: Gear pump, 5: Filter, 6: Kneader, 7: Nozzle, 7a: Nozzle hole, 8: Collector, 8a: Conveyor belt, 8b: Roller, 9: Winding device, 10: Container, 11: Container body, 11a: Opening, 11b: Internal space, 11c: Bottom wall, 11d: Side wall, 12: Lid, 13: Coffee powder, 20: Heat-sealed body, 21: First test piece, 22: Second test piece, 23: Fused portion, A: Kneaded material, B: First nonwoven fabric, C: Gas

Claims

1. A nonwoven fabric containing fibers, wherein the fibers are formed of a resin composition containing a poly(3-hydroxyalkanoate) resin, the poly(3-hydroxyalkanoate) resin contains 3-hydroxybutyrate units, the content ratio of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin contained in the nonwoven fabric is 91.0 mol% or more and 97.0 mol% or less, and the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric is 50.0 J / g or more and less than 64.5 J / g. A nonwoven fabric.

2. The nonwoven fabric according to claim 1, wherein the nonwoven fabric is a meltblown nonwoven fabric.

3. The nonwoven fabric according to claim 1 or 2, wherein the average value of the fiber diameter in the fibers is 3.3 μm or more.

4. The nonwoven fabric according to claim 1 or 2, wherein the maximum load in the MD direction of the nonwoven fabric is 0.7 N or more, and the maximum load in the CD direction of the nonwoven fabric is 0.7 N or more.

5. A heat-sealed body in which the nonwoven fabric according to claim 1 or 2 and a nonwoven fabric containing cellulose fibers are heat-sealed.

6. A coffee filter formed of the heat-sealed body according to claim 5.

7. A heat-sealed body in which a nonwoven fabric containing fibers and a molded body are heat-sealed, wherein the fibers are formed of a first resin composition containing a poly(3-hydroxyalkanoate) resin, the molded body is formed of a second resin composition containing a poly(3-hydroxyalkanoate) resin, the value obtained by subtracting the heat of fusion of the endothermic peak in the DSC curve of the molded body from the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric is 2.5 J / g or more, the poly(3-hydroxyalkanoate) resin of the fibers contains 3-hydroxybutyrate units, the content ratio of the 3-hydroxybutyrate units in the poly(3-hydroxyalkanoate) resin contained in the nonwoven fabric is 91.0 mol% or more and 97.0 mol% or less, and the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric is 50.0 J / g or more. A heat-sealed body.

8. The heat-sealed body according to claim 7, wherein the second resin composition contains a poly(3-hydroxyalkanoate) resin containing 3-hydroxybutyrate units.

9. The content ratio of the 3-hydroxybutyrate unit in the poly(3-hydroxyalkanoate) resin contained in the second resin composition is 91.0 mol% or more and 97.0 mol% or less. The heat-sealed body according to claim 8.

10. The heat-sealed body is a container including a container body having an opening and a lid for closing the opening, wherein the container body is the molded body, the lid has the nonwoven fabric, and the nonwoven fabric and the molded body are heat-sealed at the opening. The heat-sealed body according to any one of claims 7 to 9.

11. Having the heat-sealed body according to claim 10, wherein the container body has an internal space, and the internal space contains coffee powder. A coffee capsule.

12. A method for manufacturing a heat-sealed body, comprising heat-sealing a nonwoven fabric containing fibers and a molded body to obtain a heat-sealed body, wherein the fibers are formed of a first resin composition containing a poly(3-hydroxyalkanoate) resin, the molded body is formed of a second resin composition containing a poly(3-hydroxyalkanoate) resin, a value obtained by subtracting the heat of fusion of the endothermic peak in the DSC curve of the molded body from the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric is 2.5 J / g or more, the poly(3-hydroxyalkanoate) resin of the fibers contains a 3-hydroxybutyrate unit, the content ratio of the 3-hydroxybutyrate unit in the poly(3-hydroxyalkanoate) resin contained in the nonwoven fabric is 91.0 mol% or more and 97.0 mol% or less, and the heat of fusion of the endothermic peak in the DSC curve of the nonwoven fabric is 50.0 J / g or more. A method for manufacturing a heat-sealed body.

13. The heating temperature in the heat-sealing is (the melting point of the molded body + 5) °C or more and (the thermal decomposition temperature of the molded body - 5) °C or less. The method for manufacturing a heat-sealed body according to claim 12.

14. A method for manufacturing a meltblown nonwoven fabric, comprising manufacturing a meltblown nonwoven fabric containing fibers using a nozzle having nozzle holes, wherein a step (A) of obtaining a raw yarn by discharging a melt from the nozzle holes, and a step (B) of stretching the raw yarn by blowing a gas onto the raw yarn are included, the melt contains a poly(3-hydroxyalkanoate) resin, and the poly(3-hydroxyalkanoate) resin contains a 3-hydroxybutyrate unit. The content ratio of the 3-hydroxybutyrate unit in the poly(3-hydroxyalkanoate) resin contained in the melt is 91.0 mol% or more and 97.0 mol% or less, In the step (B), a method for producing a meltblown nonwoven fabric, wherein the flow rate of the gas sprayed onto the raw yarn is 900 NL / min / 600 mm or more.

15. The method for producing a meltblown nonwoven fabric according to claim 14, wherein the ratio of the opening area of the nozzle hole to the cross-sectional area of the fiber is 900 or more.