JP2024016460A - Method for manufacturing nonwoven fabric sheet and drainage bag with heat sealing function - Google Patents

Abstract

An object of the present invention is to provide a nonwoven fabric sheet that does not cause clogging even when heat-sealing properties are uniformly imparted and has excellent water drainage and solid trapping properties. [Solution] A nonwoven fabric sheet 10 has a heat sealing function, and is configured by impregnating a fibrous sheet or fibrous web 1 made of one or more fibers 1a selected from rayon, cotton, and pulp with a sealant containing a thermoplastic resin. It is a material with Therefore, the nonwoven fabric sheet 10 is favorable in terms of the natural environment, and has high strength and high rigidity. [Selection diagram] Figure 1

Description

The present invention relates to a nonwoven fabric sheet having a heat-sealing function and a method for manufacturing a drainage bag using the nonwoven fabric sheet.

Bag-like items such as plastic bags, draining bags, soup bags, etc. are made of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), etc., which are inexpensive to manufacture, have excellent durability and strength, and are easy to process. Synthetic resin films have traditionally been used. In addition, today, with the development of Internet mail order sales and logistics, many packaging materials, cushioning materials, and foaming materials are used to safely deliver products to consumers without damaging them.These materials include PE, polyurethane (PU), ), polystyrene (PS), and other synthetic resins are used.

When synthetic resins and synthetic fibers are disposed of in the natural environment or at a disposal site, they remain in their discarded state without being decomposed into water and carbon dioxide. Furthermore, when synthetic resins and fibers are disposed of in the ocean, they remain as they are or are crushed in the natural environment and remain in the form of microplastics, which can be ingested by marine organisms and birds, negatively impacting the ecosystem. affect If we do not solve this plastic waste problem, the Sustainable Development Goals (SDGs) of ``responsible production, consumption,'' ``protecting the richness of our oceans,'' and ``protecting the richness of the land,'' will not be achieved. I can't achieve my goals. For this reason, in recent years, nonwoven fabrics and bag-like products using semi-synthetic fibers, recycled fibers, natural fibers, or biodegradable fibers instead of synthetic fibers have been developed. Nonwoven fabrics using semi-synthetic fibers generally have low strength and rigidity.

Patent Document 1 discloses a garbage disposal container made of a net or nonwoven fabric, which is made of biodegradable plastic made from polylactic acid, has water permeability, and can drain water from the stored garbage. However, in the garbage processing container of Patent Document 1, rayon nonwoven fabric is not used, and there is no idea of improving the strength and rigidity of the nonwoven fabric with ethylene-containing resin or the like and imparting a heat sealing function, resulting in interfiber blockage. No problem can arise. Furthermore, there is no idea to make it independent due to its wide bottom surface.

Patent Document 2 discloses that after forming a mat mainly composed of pulp fibers with a fiber length of 0.05 to 5 mm, it is impregnated with a binder by a spraying method, the binder is fixed in a dryer, and then the opposite side is also coated with a binder. A heat-adhesive nonwoven fabric is disclosed in which the binder on the surface to be impregnated and heat-bonded is a non-crosslinked emulsion, such as ethylene-vinyl acetate copolymer (EVA). Further, a layer mainly made of rayon fibers is formed in contact with the mat layer on the surface that is not thermally bonded. However, since Patent Document 2 does not describe the particle size and shape of the non-crosslinked emulsion, it does not address particle dispersion, solid trapping, and water removal. Furthermore, since different types of binders are impregnated on both sides of the nonwoven fabric by the spraying method, manufacturing efficiency is low. Furthermore, the nonwoven fabric of Patent Document 2 consists of two layers, a mat layer of pulp fibers and a rayon fiber layer, and is not intended to improve the strength and rigidity of a single layer of rayon nonwoven fabric.

Patent Document 3 discloses a wiping cloth in which a nonwoven fabric made of cotton, rayon, etc. is impregnated with a wiping agent containing a polyvinyl acetate emulsion and general-purpose rubber latex, and then dried. However, Patent Document 3 does not describe the particle size and shape of the polyvinyl acetate emulsion, nor does it disclose particle dispersibility. Furthermore, since it is a wiping cloth, solid trapping properties and moisture removal properties are not discussed.

Japanese Patent Application Publication No. 2004-338840 Japanese Patent Application Publication No. 9-324353 Utility model registration No. 3042258

Therefore, an object of the present invention is to provide a high-strength and high-rigidity nonwoven fabric sheet that is preferable from the viewpoint of protecting the natural environment and solving the problem of plastic waste. Another object of the present invention is to provide a nonwoven fabric sheet that does not cause interfiber clogging even when a thermoplastic resin-containing sealing agent is uniformly dispersed to impart heat-sealing properties to the entire surface and has excellent water drainage and solid trapping properties. Furthermore, it is an object of the present invention to provide a method for manufacturing a draining bag that can be composted without any hassle.

The nonwoven fabric sheet 10 according to the present invention has a heat sealing function by applying a thermoplastic resin-containing sealing agent to one or more fiber sheets or fiber webs 1 selected from rayon, cotton, and pulp.

Since the nonwoven fabric sheet 10 according to the present invention is composed of a fiber sheet or fiber web 1 that uses 100% of fibers 1a selected from rayon, cotton, and pulp, it does not remain in the natural environment, and can protect the animal and plant environment, ecosystem, and scenery. , which is preferable in terms of hygiene. In addition, since it contains a sealing agent containing thermoplastic resin 2, it not only imparts a heat sealing function but also enhances the mechanical strength and rigidity of the fiber sheet or web 1 made of non-synthetic fibers 1a, that is, rayon, cotton, and pulp. For example, a self-supporting draining bag 50 can be formed. The thermoplastic resin 2 contained as a sealant is adhered between the fibers of the fiber sheet or fiber web 1 to form an appropriate space 11 and resistance, so that, for example, in the drainage bag 50 formed from the nonwoven fabric sheet 10, It has excellent drainage properties without causing clogging, and has excellent properties (catch rate) for capturing solids such as garbage.

The method for manufacturing the draining bag 50 according to the present invention includes the steps of forming an inward fold 51a in the nonwoven fabric sheet 10, and folding the nonwoven fabric sheet 10 so that both ends in the width direction meet together to form an open end 87 of the nonwoven fabric sheet 10. After folding the open end 87 outward to form the folded piece 56, a plurality of joints 83 spanning the width direction of the nonwoven fabric sheet 10 are formed at regular intervals in the length direction of the nonwoven fabric sheet 10, and between the joints 83, The method includes a step of forming the main body sheet 64, and a step of cutting the joint portion 83 into approximately two halves to sequentially separate the bag main body 54. The draining bag 50 obtained by the manufacturing method according to the present invention is strong, can stand on its own, and is difficult to tear during use. In addition, since the draining bag 50 is made of the fiber 1a selected from rayon, cotton, and pulp, there is no need to separate dust (garbage) from the draining bag 50, and the dust can be stored in the draining bag 50 without any trouble. Can be easily composted.

Since the nonwoven fabric sheet according to the present invention does not use synthetic fibers, it is preferable to solve the problem of plastic waste from the viewpoint of preserving the natural environment, and because it contains a thermoplastic resin-containing sealant between the fibers, it strengthens strength, rigidity, and toughness. For example, it is possible to form a drainage bag that can stand on its own and is hard to tear during use. In addition, clogging due to interfiber blockage does not occur, and both water drainage and solid trapping properties can be improved, making it ideal for solid-liquid separation applications. In the method for manufacturing a draining bag according to the present invention, dust can be easily composted while being stored in the draining bag without being removed from the bag.

A sectional view showing a nonwoven fabric sheet according to the present invention (a) An enlarged cross-sectional view of the nonwoven fabric sheet shown in FIG. 1, and (b) an enlarged cross-sectional view showing the nonwoven fabric sheet in a state where the fibers are closed. Schematic diagram showing the method for manufacturing a nonwoven fabric sheet A front view showing a draining bag using a nonwoven fabric sheet according to the present invention A three-dimensional diagram schematically showing an open state of a draining bag using a nonwoven fabric sheet according to the present invention (a) A partial sectional view taken along line II of the draining bag shown in FIG. 4, and (b) A partial sectional view showing the state where the open end of the draining bag is covered. A process diagram schematically showing a method for manufacturing a draining bag according to the present invention Schematic diagram showing the composting process

Embodiments of a nonwoven fabric sheet and a method of manufacturing a drainage bag using the nonwoven fabric sheet according to the present invention will be described with reference to FIGS. 1 to 8. The following embodiments and each drawing are illustrative and should not be interpreted as limiting the present invention.

A nonwoven fabric sheet 10 according to the present invention shown in FIGS. 1 and 2(a) includes a fiber sheet (or fiber web) 1 made of fibers 1a that are not synthetic fibers, and a sealant impregnated into the fiber sheet 1. include. The non-synthetic fibers 1a are one or more fibers selected from recycled fibers such as rayon, semi-synthetic fibers such as acetate, and natural fibers such as pulp, cotton, and hemp. Rayon fiber is particularly preferred. In this specification, the term "synthetic fiber" is used to mean "does not include semi-synthetic fibers, recycled fibers, or natural fibers." The sealant is a thermoplastic resin (ethylene-containing resin) 2 with an average particle diameter of 0.1 to 1.0 μm, and is impregnated and dispersed between the fibers 1a of the fiber sheet 1 to impart a heat sealing function. . If the average particle diameter of the thermoplastic resin 2 is less than 0.1 μm, the diameter is small, so when impregnating the liquid 12 containing sealant (dispersion, emulsion, etc.) by dipping (Fig. 3), heat is generated between the fibers 1a. Plastic resin 2 is difficult to remain and easily falls off. If the average particle diameter of the thermoplastic resin 2 exceeds 1 μm, the particles are too large to pass between the fibers and the thermoplastic resin 2 is not uniformly dispersed, so that the fiber sheet 1 as a whole is not provided with heat-sealing properties. The diameter of the fibers 1a of the fiber sheet 1 is 5 to 50 μm.

The fibers of the fiber sheet or web 1 have a fineness of 1 to 5 dtex. When the fineness is less than 1 dtex, the fibers become overcrowded, resulting in poor drainage performance. If it exceeds 5 dtex, the fibers will be thick and there is a risk that contained substances such as dust may escape, and the number of fibers will decrease, resulting in a decrease in strength and rigidity. Most preferably, the fineness is 1.3 to 2.2 dtex. The nonwoven fabric of the fibrous sheet or fibrous web 1 is a spunlace nonwoven fabric, a needle punch nonwoven fabric, a chemical bond nonwoven fabric, an airlaid nonwoven fabric, or a spunbond nonwoven fabric, with spunlace nonwoven fabrics and needle punch nonwoven fabrics being particularly preferred. The fiber sheet or fibrous web 1 can have a basis weight of 17 to 100 g/m ² , particularly preferably a basis weight of 25 to 80 g/m ² . If the basis weight is less than 25 g/m ² , the fiber sheet or fiber web 1 will be thin and its strength and rigidity will be reduced, making it difficult to stand on its own and stand up when used, for example, in the draining bag 50. If it exceeds 80 g/m ² , the strength and rigidity are high and the self-reliance is improved, but the drainage bag 50 has poor drainage performance and liquid permeability, and is overly designed as the draining bag 50 is ultimately discarded. Bags do not release enough stock ingredients, and cooking bags used in pots have difficulty transmitting heat to the entire food.

The thermoplastic resin (ethylene-containing resin) 2 is preferably an ethylene-methacrylic acid (EMMA) copolymer or an ethylene-vinyl acetate (EVA) copolymer, or preferably an ionomer of any of the above polymers. , as shown in FIG. 2(a), comprises a bonding portion 2a that is bonded to the fiber 1a and a substantially spherical portion 2b other than the bonding portion 2a. Ionomer is a substance containing metal ions and polymers, and is a synthetic resin that uses the cohesive force of metal ions to form polymer aggregates. Ionomers are used to impart heat sealability, transparency, toughness, abrasion resistance, and the like.

In this embodiment, since a sealing agent containing any of the above-mentioned copolymers (this also includes an ionomer) is used as an aqueous emulsion, a single-layer fiber sheet or fiber web 1 made of fibers 1a, particularly rayon fibers, is machined. Significantly improves mechanical strength and rigidity. In addition, the rayon fiber 1a generally has a smooth surface and therefore does not have good solid-capturing properties, but by attaching the thermoplastic resin 2a to the surface of the rayon fiber 1a through the bonding part 2a, the surface of the rayon fiber 1a has complex irregularities. to improve solid trapping performance.

The method for manufacturing the nonwoven fabric sheet 10 will be described below.

This embodiment mainly includes a step of manufacturing a fiber sheet (or fiber web) 1 by a spunlace method or a needle punch method, and a step of manufacturing a nonwoven fabric sheet 10 from the fiber sheet 1. In the process of manufacturing the fiber sheet 1, first, relatively short defibrated fibers (stable fibers) are deposited from a jetting device onto a net installed at the bottom. In this embodiment, fibers with a fineness of 1 to 5 dtex and a fiber length of 32 to 64 mm are used. Specifically, any fiber selected from rayon, cotton, and pulp is used. The fiber length does not significantly affect the physical properties of the fiber sheet 1, as long as it is 32 to 64 mm, which is the typical length used in carding methods. Preferably it is 38 to 44 mm. The fiber web deposited on the net is three-dimensionally intertwined between the fibers using a high-pressure water stream in the spunlace method or a plurality of needles in the needle punch method to form the fiber sheet 1.

In the process of manufacturing the nonwoven fabric sheet 10, first, the fiber sheet (or fiber web) 1 manufactured from, for example, rayon fibers 1a is soaked with a sealant-containing liquid (dispersion or emulsion) by dipping, spraying, or coating. ) Impregnated with 12. FIG. 3 shows a process in which the fiber sheet 1 is continuously passed through a tank 8 containing the sealant-containing liquid 12 to immerse the fiber sheet 1 in the sealant-containing liquid 12. The dipping method can efficiently produce the nonwoven fabric sheet 10. By impregnating the sealant-containing liquid 12, the substantially spherical thermoplastic resin 2 with an average particle diameter of 0.1 to 1.0 μm contained therein is dispersed throughout the fiber sheet 1, uniformly imparting a heat sealing function. , also improves mechanical strength and rigidity. Here, "substantially spherical" means not only a perfect sphere but also a substantially spherical shape in appearance, even if it is somewhat distorted.

Next, the fiber sheet (or fiber web) 1 impregnated with the sealant-containing liquid 12 and having the thermoplastic resin 2 dispersed therein is led out of the tank 8 and dried by a drying device 9 shown in FIG. 3. During the drying process, the temperature of the fiber sheet 1 became 50 to 150°C, and the thermoplastic resin 2 melted only on the surface while maintaining its substantially spherical shape, and adhered to the fibers 1a as shown in Figure 2(a). A bonding portion 2a of the thermoplastic resin 2 and a substantially spherical portion 2b that maintains its shape except for the bonding portion 2a are formed. Since the thermoplastic resin 2 does not completely melt, interfiber blockage 21 (FIG. 2(b)) does not occur, and in the present invention, even if the thermoplastic resin 2 is dispersed throughout the fiber sheet 1, liquid permeability, drainage performance, and Dust trapping performance can be improved. Since the thermoplastic resin 2a is substantially spherical particles, it can smoothly penetrate and be dispersed between the fibers 1a of the fiber sheet 1 by any impregnation method, resulting in a high-quality nonwoven fabric with even and uniform heat sealing properties. Sheets 10 are obtained.

4 and 5 show embodiments of a drainage bag 50 manufactured from the nonwoven fabric sheet 10 according to the present invention in a folded state and an open state. The draining bag 50 has a bottom edge 51 having an inward fold 51a, a pair of upper edges 52, 52a, 52b forming an opening 86, and a pair of sheet-like bags extending from the bottom edge 51 to the upper edge 52. The bag body 54 is surrounded by a bottom edge 51, a top edge 52, and a pair of sealed sides 53, which partially join the body 54. A pair of folded pieces 56, 56a, 56b are provided which are folded outward from the bag body 54 via the upper edge 52 with the upper edge 52 as a fold. The draining bag 50 has a bag body 54 and a folded piece 56 in contact with each other to form a double structure (FIG. 6) near the upper edge 52.

The folded portion 51a in FIG. 4, which is called a gusset or gusset, has a folded height (gusset width) (E) of 10 to 70 mm, preferably 20 to 60 mm. If the gusset width (E) is large, a large area of the bottom edge 51 can be formed when the draining bag 50 is opened (Fig. 5), and the draining bag 50 maintains its self-supporting stability even if it absorbs moisture in the kitchen, for example. can. The pair of upper edges 52, 52a, 52b form a fold that connects the bag body 54 and the folded piece 56 and folds the folded piece 56 outward by about 180 degrees from the bag body 54, and between the upper ends of the pair of sealing side parts 53. As shown in FIG. 5, one upper edge 52a and the other upper edge 52b are provided. In this embodiment, the heights from the bottom edge 51 to one upper edge 52a and the other upper edge 52b are approximately equal.

The length (B) between the upper edge 52 and the bottom edge 51 of the draining bag 50 in FIG. It is 0.3 to 1 times the length (A) of 51. If the length (B/A) of the sealing side portion 53 is less than 0.3 times the length of the bottom edge 51, the height of the draining bag 50 will be small compared to the area of the bottom edge 51, and the self-standing stability will increase. However, the draining bag 50 is shallow and the amount of dust it can contain is too small. When B/A exceeds 1, the self-supporting function deteriorates and the draining bag 50 collapses. It is particularly preferred that the length (B) of the sealing side portion 53 is 0.45 to 0.73 times the length (A) of the bottom edge 51. The rectangular sheet-shaped bag body 54 forms a cavity between the pair of bag bodies 54 when opened as shown in FIG. 5, and dust can be stored in the cavity.

FIG. 6(a) shows a partial sectional view taken along the line II of the draining bag 50 shown in FIG. . 4 and 5, the pair of upper edges 52 have one upper edge 52a and the other upper edge 52b between the pair of sealing side parts 53 to form an opening 86, and the pair of folded pieces 56 are , one folded piece 56a connected to one upper edge 52a, and the other folded piece 56b connected to the other upper edge 52b. When one folded piece 56a is folded back in the direction of arrow F in FIG. 6(a), one folded piece 56a has an opening 86, the other upper edge 52b, and the other folded piece 56b, as shown in FIG. 6(b). A coated state can be formed by coating at least a portion of the. Due to the covering state, the opening 86 can be sufficiently covered, and the dust contained in the draining bag 50 will not be discharged to the outside.

Hereinafter, with reference to FIG. 7, an embodiment of a method for manufacturing a drainage bag 50 using the nonwoven fabric sheet 10 according to the present invention will be described.
In the first stage, the prepared continuous sheet 74 of the nonwoven fabric sheet 10 is movably arranged in a processing device (not shown), and is conveyed in the length direction of the continuous sheet 74, that is, in the feeding direction (arrow M) (Fig. 7(a)). In the second step, the continuous sheet 74 is folded in half in the K direction so that both widthwise ends of the continuous sheet 74 are aligned, while forming an inward fold (gusset) 51a of the bottom edge 51 near the center line 85 of the continuous sheet 74. An open end 87 of the continuous sheet 74 is formed (FIG. 7(b)).

In the third step, the pair of open ends 87 of the continuous sheet 74 of the nonwoven fabric sheet 10 are folded outward (in the direction of arrow L), and the folded pieces 56 and the upper edge 52 connecting the folded pieces 56 and the bag body 54 are folded. (Fig. 7(c)). In the third step, after the folded pieces 56 are formed, a plurality of long joint parts 83 in the width direction of the continuous sheet 74 are formed at fixed intervals at the planned formation location 43 of the sealing end part 53 (FIG. 7(d) )). A plurality of joints 83 extending from the bottom edge 51 to the top edge 52 are formed at regular intervals in the feeding direction (lengthwise direction of the continuous sheet 74) (M) by thermocompression bonding using a roller (not shown). , the main body sheet 64 of the bag-like material is formed continuously between the joints 83. Finally, the joint portion 83 is cut approximately parallel to the width direction of the continuous sheet 74 so as to divide the joint portion 83 into approximately two equal parts. That is, by cutting the joint portion 83 along the line PP in a direction substantially perpendicular to the feeding direction (M), the bag body 54 can be separated one by one, and a plurality of draining bags 50 can be continuously manufactured.

Hereinafter, a composting method using the draining bag 50 obtained by the above manufacturing method according to the present invention will be described. First, as shown in FIG. 5, the pair of upper edges 52a and 52b of the draining bag 50 are opened, and the bottom edge 51 is opened to form the bottom surface 61 substantially horizontally, so that the draining bag 50 is made to stand on its own in, for example, a kitchen sink. Dust, especially raw garbage such as food scraps and leftovers, is disposed of and stored in a free-standing draining bag 50, and moisture in the dust is removed through the bottom surface 61. After the dust reaches an appropriate amount, the upper edges 52, 52a, 52b and the opening 86 of the draining bag 50 containing the dust are closed with one folded piece 56a as shown in FIG. 6(b) to prevent the dust from being stored. finish.

FIG. 8(a) shows a state in which the draining bag 50 with the opening 86 closed by one folded piece 56a is placed in a composting device (not shown). There is no need to take out the dust contained inside from the draining bag 50. The nonwoven fabric sheet 10 of the draining bag 50 placed in the composting device is decomposed by the microorganisms 62, and an opening 61a is formed as shown in FIG. 8(b). Microorganisms 62 enter through the opening 61a, and the dust inside the draining bag 50 is decomposed by the microorganisms 62. As shown in FIG. 8(c), the opening 61a of the draining bag 50 becomes larger, and the biodegradation of the dust by microorganisms progresses rapidly, and eventually, almost no draining bag 50 remains, and it goes into the composting device along with the dust. It decomposes into water, carbon dioxide and a small residue. A small residue can be used, for example, as fertilizer.

The non-woven fabric sheet of the present invention can be used in draining bags for disposing of food waste in the kitchen, plastic shopping bags for storing purchased products, soup bags for storing bonito flakes etc. to extract soup stock, and cooking bags for storing ingredients to be simmered and putting them directly into a pot. It can be used for a variety of purposes, including cushioning materials for packaging products during transportation, sanitary products such as masks, towels, sanitary products, and diapers, and medical products such as gauze, gloves, caps, and protective clothing.

1...Fiber sheet or fiber web, 1a...Fiber (rayon fiber), 2...Thermoplastic resin (ethylene-containing resin), 2a...Joint part, 2b...Substantially spherical part, 10...Nonwoven fabric sheet, 12...liquid containing sealant, 50...draining bag, 51a...infolded part, 52,52a,52b...upper edge, 54...bag body, 61a...opening, 62...microorganisms, 74...・Continuous sheet, 83...Joint part, 86...Open end,

Claims (3)

A nonwoven fabric sheet characterized by having a heat sealing function by applying a thermoplastic resin-containing sealing agent to one or more fiber sheets or fiber webs selected from rayon, cotton, and pulp. The nonwoven fabric sheet according to claim 1, which is used for plastic shopping bags, draining bags, soup bags, cooking bags, tea bags, or cushioning materials. Forming an inward fold in the nonwoven fabric sheet according to claim 1, and folding the nonwoven fabric sheet so that both widthwise ends of the nonwoven fabric sheet are aligned to form an open end of the nonwoven fabric sheet;
After the open end is folded outward to form a folded piece, a plurality of connection parts spanning the width direction of the nonwoven fabric sheet are formed at regular intervals in the length direction of the nonwoven fabric sheet, and a main sheet is formed between the connection parts. ,
A method for producing a draining bag, comprising the step of cutting the joint part into approximately two equal parts and sequentially separating the bag body.

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