Pull-out bag

Abstract

The present invention provides an extraction bag that, even when biodegradable polylactic acid resin is used for the resin of the nonwoven fabric sheet that constitutes the extraction bag, and for the resin used for the laminating component of the extraction bag, allows for the attachment component to be properly bonded to the sheet without damaging the nonwoven fabric. [Solution] An extraction bag 100 is formed by joining a spunbond nonwoven fabric layer 10 containing polylactic acid resin and an accessory member 20, wherein a laminate layer 21 containing polylactic acid resin is provided on at least the surface of the accessory member 20 that is in contact with the spunbond nonwoven fabric layer 10, and the degree of crystallinity of the polylactic acid resin contained in the laminate layer 21 is set to be smaller than the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer 10.

Description

[Technical Field]

[0001] The present invention relates to an extraction bag comprising a spunbond nonwoven fabric layer containing polylactic acid resin and an attached member, a method for manufacturing an extraction bag, and a sheet for an extraction bag, and a method for manufacturing a sheet for an extraction bag. [Background technology]

[0002] To reduce the environmental impact when disposing of extraction bags used for extracting coffee, tea, broth, etc., biodegradable materials have been developed for the sheets that make up the bags (see, for example, Patent Documents 1 and 2).

[0003] The coffee extraction sheet material described in Patent Document 1 is formed from a meltblown ultrafine fiber nonwoven fabric made of a biodegradable thermoplastic polymer. The examples in the same document describe a drip-type coffee filter formed using a meltblown nonwoven fabric made of polylactic acid ultrafine fibers.

[0004] The extraction sheet described in Patent Document 2 is made by laminating a melt-blown nonwoven fabric layer and a spunbond nonwoven fabric layer, both made of polylactic acid-based resin. Figure 2 of the same document shows a tea bag formed using this extraction sheet, with a tag attached to the surface for picking it up with the fingertips.

[0005] The extraction sheets described in Patent Documents 1 and 2 above can reduce environmental impact because, even if the material to be extracted is buried in the soil with the bag still inside after use, the extraction sheet will decompose together with the material to be extracted by microorganisms. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2000-336570 [Patent Document 2] Japanese Patent Publication No. 2016-168569 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] To reduce the environmental impact of extraction bags, it is desirable to use biodegradable materials not only for the sheet but also for all attached components. Various biodegradable materials exist, such as polylactic acid, polyhydroxyalkanoate, and polybutylene succinate, but it is preferable to use the same polylactic acid resin for all components so that they have similar decomposition characteristics. While some existing polylactic acid resins have different melting points, general-purpose materials generally have approximately the same melting point. Therefore, if the same polylactic acid resin is used for the resin used in the nonwoven fabric of the extraction bag and the resin used for laminating the attached components, there is a risk that the fibers forming the nonwoven fabric may be damaged when heated for bonding purposes.

[0008] In this regard, the coffee extraction sheet material described in Patent Document 1 may become brittle due to heat damage, and the filter may detach from the locking part, which is an attached component, due to the load during coffee extraction. The extraction sheet described in Patent Document 2 may have holes in the sheet when the tag is peeled off the bag if the adhesive force of the tag to the bag is too strong. On the other hand, if the adhesive force of the tag to the bag is too weak, the tag may detach from the bag during the filling process of the bag with the extract, which may cause manufacturing defects.

[0009] The present invention has been made in view of the above problems, and aims to provide an extraction bag, a method for manufacturing an extraction bag, an extraction bag sheet, and a method for manufacturing an extraction bag sheet, which enable the attachment to be properly joined to the sheet without damaging the nonwoven fabric, even when a biodegradable polylactic acid resin is used as the resin for the nonwoven fabric sheet constituting the extraction bag and the resin for laminating the attachment to the extraction bag. [Means for solving the problem]

[0010] The characteristic configuration of the extraction bag according to the present invention, which solves the above problems, is as follows: An extraction bag comprising a spunbond nonwoven fabric layer containing polylactic acid resin and an attached component, A laminate layer containing polylactic acid resin is provided on at least the surface of the accessory member that is in contact with the spunbond nonwoven fabric layer. The degree of crystallinity of the polylactic acid resin contained in the laminate layer is set to be lower than the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer.

[0011] In this extraction bag configuration, the degree of crystallinity of the polylactic acid resin contained in the laminate layer of the attached component is set to be lower than that of the polylactic acid resin contained in the spunbond nonwoven fabric layer. Therefore, when heated for bonding, only the polylactic acid resin contained in the laminate layer of the attached component is softened, and the softened laminate layer is embedded between the fibers of the spunbond nonwoven fabric layer, integrating the attached component with the spunbond nonwoven fabric layer. At this time, the polylactic acid resin contained in the spunbond nonwoven fabric layer has not yet softened at the temperature at which the polylactic acid resin in the laminate layer softens, so the spunbond nonwoven fabric layer is not damaged and can maintain its function as a filter. Furthermore, because the adhesive force between the spunbond nonwoven fabric layer and the attached component is appropriately controlled, there is no risk of damaging the spunbond nonwoven fabric layer even when the attached component is peeled off.

[0012] In the extraction bag according to the present invention, It is preferable that the difference between the degree of crystallinity of the polylactic acid resin contained in the laminate layer and the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer is set to 10% or more.

[0013] In this extraction bag configuration, the difference between the degree of crystallinity of the polylactic acid resin contained in the laminate layer and the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer is set to 10% or more. As a result, only the polylactic acid resin contained in the laminate layer, which has a lower degree of crystallinity, softens, and the softened laminate layer can interlock with the fibers of the spunbond nonwoven fabric layer, resulting in a strong bond and integration. At this time, since the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer is 10% or more higher than that of the polylactic acid resin contained in the laminate layer, the polylactic acid resin contained in the spunbond nonwoven fabric layer has not yet softened at the temperature at which the polylactic acid resin contained in the laminate layer softens, and the structure of the spunbond nonwoven fabric layer is maintained. Therefore, the spunbond nonwoven fabric layer is not damaged and can maintain its function as a filter.

[0014] In the extraction bag according to the present invention, It is preferable that a meltblown nonwoven fabric layer containing polylactic acid resin is provided on the spunbond nonwoven fabric layer.

[0015] According to this extraction bag configuration, a melt-blown nonwoven fabric layer containing polylactic acid resin is provided on top of a spunbond nonwoven fabric layer. Therefore, the overall environmental impact of the extraction bag is reduced, while the laminated structure of the spunbond nonwoven fabric layer and the melt-blown nonwoven fabric layer provides excellent filtering functionality.

[0016] The characteristic configuration of the method for manufacturing an extraction bag according to the present invention, which solves the above problems, is as follows: A method for manufacturing an extraction bag comprising a spunbond nonwoven fabric layer containing polylactic acid resin and an attached component, A laminate layer containing polylactic acid resin is provided on at least the surface of the accessory member that is in contact with the spunbond nonwoven fabric layer. The degree of crystallinity of the polylactic acid resin contained in the laminate layer is set to be lower than that of the polylactic acid resin contained in the spunbond nonwoven fabric layer. The method for joining the spunbond nonwoven fabric layer and the attached member involves performing a heating step that applies a temperature 30 to 100°C higher than the glass transition temperature Tg of the polylactic acid resin.

[0017] According to the manufacturing method of the extraction bag of this configuration, the crystallinity of the polylactic acid resin contained in the laminate layer of the accessory member is set to be smaller than the crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer. Therefore, when joining the spunbond nonwoven fabric layer and the accessory member, by performing a heating process of applying a temperature 30 to 100 °C higher than the glass transition temperature Tg of the polylactic acid resin, only the polylactic acid resin contained in the laminate layer of the accessory member is softened, and the softened laminate layer is allowed to penetrate between the fibers of the spunbond nonwoven fabric layer, so that the accessory member can be integrated with the spunbond nonwoven fabric layer. At this time, since the polylactic acid resin contained in the spunbond nonwoven fabric layer is not yet softened at the temperature at which the polylactic acid resin contained in the laminate layer softens, the spunbond nonwoven fabric layer can maintain its function as a filter without being damaged. Also, since the adhesive force between the spunbond nonwoven fabric layer and the accessory member is appropriately controlled, there is no risk of damaging the spunbond nonwoven fabric layer even when the accessory member is peeled off from the spunbond nonwoven fabric layer.

[0018] The characteristic configuration of the sheet for an extraction bag according to the present invention for solving the above problems is a sheet for an extraction bag formed by joining a spunbond nonwoven fabric layer containing a polylactic acid resin and an accessory member, wherein a laminate layer containing a polylactic acid resin is provided on at least the surface of the accessory member that contacts the spunbond nonwoven fabric layer, and the crystallinity of the polylactic acid resin contained in the laminate layer is set to be smaller than the crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer.

[0019] According to the sheet for the extraction bag of this structure, the crystallinity of the polylactic acid resin contained in the laminate layer of the attached member is set to be smaller than the crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer. Therefore, when heating for joining, only the polylactic acid resin contained in the laminate layer of the attached member is softened, and the softened laminate layer can be made to penetrate between the fibers of the spunbond nonwoven fabric layer to integrate the attached member with the spunbond nonwoven fabric layer. At this time, since the polylactic acid resin contained in the spunbond nonwoven fabric layer has not yet softened at the temperature at which the polylactic acid resin contained in the laminate layer softens, the spunbond nonwoven fabric layer can maintain its function as a filter without being damaged. Also, since the adhesive force between the spunbond nonwoven fabric layer and the attached member is appropriately controlled, there is no risk of damaging the spunbond nonwoven fabric layer even when the attached member is peeled off from the spunbond nonwoven fabric layer.

[0020] The characteristic configuration of the manufacturing method of the sheet for the extraction bag according to the present invention for solving the above problems is A manufacturing method of a sheet for an extraction bag formed by joining a spunbond nonwoven fabric layer containing a polylactic acid resin and an attached member, wherein a laminate layer containing a polylactic acid resin is provided on at least the surface of the attached member that contacts the spunbond nonwoven fabric layer, the crystallinity of the polylactic acid resin contained in the laminate layer is set to be smaller than the crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer, and when joining the spunbond nonwoven fabric layer and the attached member, a heating step of applying a temperature 30 to 100 °C higher than the glass transition temperature Tg of the polylactic acid resin is carried out.

[0021] According to the manufacturing method for the extraction bag sheet with this configuration, the degree of crystallinity of the polylactic acid resin contained in the laminate layer of the accessory component is set to be lower than the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer. Therefore, when joining the spunbond nonwoven fabric layer and the accessory component, a heating process is carried out that applies a temperature 30 to 100°C higher than the glass transition temperature Tg of the polylactic acid resin. This softens only the polylactic acid resin contained in the laminate layer of the accessory component, and the softened laminate layer is embedded between the fibers of the spunbond nonwoven fabric layer, thereby integrating the accessory component with the spunbond nonwoven fabric layer. At this time, the polylactic acid resin contained in the spunbond nonwoven fabric layer has not yet softened at the temperature at which the polylactic acid resin contained in the laminate layer softens, so the spunbond nonwoven fabric layer is not damaged and can maintain its function as a filter. Furthermore, because the adhesive strength between the spunbond nonwoven fabric layer and the attached components is appropriately controlled, there is no risk of damaging the spunbond nonwoven fabric layer even if the attached components are peeled off from it. [Brief explanation of the drawing]

[0022] [Figure 1] Figure 1 is a schematic cross-sectional view showing the layered structure of an extraction bag (drip bag) according to the first embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing the layered structure of an extraction bag (drip bag) according to a second embodiment of the present invention. [Figure 3] Figure 3 is a schematic cross-sectional view showing the layered structure of an extraction bag (tea bag) according to the third embodiment of the present invention. [Modes for carrying out the invention]

[0023] The following describes in detail embodiments of the extraction bag, the method for manufacturing the extraction bag, the sheet for the extraction bag, and the method for manufacturing the sheet for the extraction bag according to the present invention. Note that the shape and size relationships of the layer structure of the extraction bag shown in each figure have been simplified and exaggerated as appropriate to facilitate understanding of the invention, and do not necessarily reflect the actual shape and size relationships. Furthermore, the present invention is not intended to be limited to the configurations described below.

[0024] [Sheet for extraction bags] The extraction bag sheet of the present invention basically comprises a laminate formed by laminating a spunbond nonwoven fabric layer containing polylactic acid resin and an accessory member. The accessory member has a material containing polylactic acid resin laminated to its surface (at least the surface in contact with the spunbond nonwoven fabric layer). Known lamination methods include extrusion lamination, dry lamination, heat lamination, and wet lamination, but as will be described later, any processing method is acceptable as long as the degree of crystallinity of the polylactic acid resin contained in the laminate layer is smaller than the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer. Examples of accessory parts include a locking piece for securing the extraction bag made from the extraction bag sheet of the present invention to a container such as a cup, a tag with a thread attached to the extraction bag, and a thin plate-like member for moving the extraction bag up and down in hot water. A meltblown nonwoven fabric layer containing polylactic acid resin is provided on top of the spunbond nonwoven fabric layer as needed.

[0025] [Extraction bag] The extraction bag of the present invention is manufactured by forming the sheet for the extraction bag of the present invention into a bag shape. Methods for bag manufacturing include heat or ultrasonic welding, bonding with adhesive, and stitching with thread. Three representative embodiments of the extraction bag of the present invention will be described below.

[0026] <First Embodiment> Figure 1 is a schematic cross-sectional view showing the laminated structure of an extraction bag according to a first embodiment of the present invention. This extraction bag is used as a drip bag 100 in which a spunbond nonwoven fabric layer 10 and a cardboard sheet 20 as an accessory member are joined together.

[0027] [Spunbond nonwoven fabric layer] The spunbond nonwoven fabric layer 10 functions as a filter for extracting the desired components. The spunbond nonwoven fabric layer 10 is formed by drawing a high-speed gas stream onto molten resin extruded from a spinning nozzle, stretching and cooling it to form fibers, and then accumulating these fibers on a collector to form a web. In the drip bag 100 according to the first embodiment, polylactic acid resin, a biodegradable resin, is used as the resin constituting the spunbond nonwoven fabric layer 10. The basis weight of the spunbond nonwoven fabric layer 10 is 8-20 g / m². 2 It is preferable to use 12-20 g / m². 2 This is preferable.

[0028] [Cardboard] The cardboard 20 is a component that forms a locking piece for securing the drip bag 100 to a container such as a cup. Therefore, in order to have a certain degree of rigidity, the basis weight of the cardboard is 150-300 g / m². 2 It is preferable to do so.

[0029] The cardboard 20 is provided with a laminate layer 21 on at least the surface in contact with the spunbond nonwoven fabric layer 10, on which a laminate material mainly composed of a thermoplastic resin is applied. In the drip bag 100 according to the first embodiment, polylactic acid resin, which is a biodegradable resin, is used as the resin for forming the laminate layer 21, similar to the spunbond nonwoven fabric layer 10. The thickness of the laminate layer 21 is preferably 20 to 80 μm, and more preferably 40 to 80 μm.

[0030] [Polylactic acid resin] The drip bag 100 according to the first embodiment is formed by bonding a spunbond nonwoven fabric layer 10 to a cardboard sheet 20. The bonding is performed by laminating the spunbond nonwoven fabric layer 10 and the cardboard sheet 20 and heating them to soften the polylactic acid resin contained in the laminate layer 21 on the surface of the cardboard sheet 20, and then allowing the softened polylactic acid resin to penetrate into the gaps in the spunbond nonwoven fabric layer 10. Therefore, in order to properly bond the cardboard sheet 20 to the spunbond nonwoven fabric layer 10, it is important to understand the mechanism by which the polylactic acid resin softens and to perform the bonding (heating) under appropriate conditions. Here, polylactic acid resin is a crystalline polymer that can undergo a phase transition between a crystalline phase and an amorphous phase. Like other general polymer materials, polylactic acid resin gradually softens when it exceeds its glass transition temperature, but it softens more easily when it has a large amorphous portion and does not soften easily in the crystalline state. Furthermore, the higher the degree of crystallinity of the polylactic acid resin, the higher its heat resistance.

[0031] The inventors of this invention believe that the degree of crystallinity of the polylactic acid resin is a factor that greatly influences the quality of bonding when bonding a cardboard 20, which has a laminate layer 21 containing polylactic acid resin, to a spunbond nonwoven fabric layer 10 containing polylactic acid resin. They have found that by appropriately setting the relationship between the degree of crystallinity of the polylactic acid resin on the spunbond nonwoven fabric layer 10 side and the degree of crystallinity of the polylactic acid resin on the cardboard 20 (laminate layer 21) side, it is possible to bond the cardboard 20 to the spunbond nonwoven fabric layer 10 without damaging the spunbond nonwoven fabric layer 10.

[0032] The degree of crystallinity of polylactic acid resin can be determined as follows. First, a test specimen cut from the spunbond nonwoven fabric layer 10 and the laminate layer 21 is placed in a differential scanning calorimeter (DSC), and the temperature is increased at a predetermined rate from a temperature lower than the glass transition temperature Tg (approximately 50-60°C) of the polylactic acid resin to a temperature higher than the melting point Tm (approximately 150-170°C). For example, the temperature is increased from 30°C to 240°C at a rate of 10°C / min. During this heating process, the amorphous portion of the polylactic acid resin undergoes a phase transition to crystal, and as the temperature is further increased, the crystals melt, ultimately resulting in a molten state. Here, if the heat of crystallization when the amorphous portion of the polylactic acid resin undergoes a phase transition to crystal is ΔHc, and the heat of fusion when the crystals of the polylactic acid resin melt is ΔHm, then the degree of crystallinity χc (%) of the polylactic acid resin is given by the following equation (1): χc(%) = (ΔHm-ΔHc) / Q × 100 ···(1) It is calculated from the following. Note that Q is the heat of fusion for a perfect crystal, and in the case of polylactic acid resin, Q = 93 J / g.

[0033] According to new findings obtained by the present inventors, in order to bond the cardboard 20 to the spunbond nonwoven fabric layer 10 without problems, it is essential to set the degree of crystallinity of the polylactic acid resin contained in the laminate layer 21 of the cardboard 20 to be lower than the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer 10. For example, the degree of crystallinity of the polylactic acid resin contained in the laminate layer 21 is set to 1-40%, and the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer 10 is set to 30-60%. Here, it is preferable that the difference between the degree of crystallinity of the polylactic acid resin contained in the laminate layer 21 and the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer 10 is set to 10% or more. In this case, the polylactic acid resin contained in the laminate layer 21 of the cardboard 20 will be easily softened, while the polylactic acid resin contained in the spunbond nonwoven fabric layer 10 will be less likely to soften. In this case, if the spunbond nonwoven fabric layer 10 and the paperboard 20 are bonded at a temperature higher than the glass transition temperature Tg of the polylactic acid resin (for example, Tg + 30°C to 100°C), only the polylactic acid resin contained in the laminate layer 21 of the paperboard 20, which has a low degree of crystallinity, will soften. The softened laminate layer 21 will then bite into the spaces between the fibers of the spunbond nonwoven fabric layer 10, causing the paperboard 20 to bond firmly to the spunbond nonwoven fabric layer 10 and become one. At this time, the polylactic acid resin contained in the spunbond nonwoven fabric layer 10 has a higher degree of crystallinity than the polylactic acid resin contained in the laminate layer 21, so it has not yet softened at the temperature at which the polylactic acid resin in the laminate layer 21 softens, and the structure of the spunbond nonwoven fabric layer 10 is maintained. In this way, by setting the degree of crystallinity of the polylactic acid resin contained in the laminate layer 21 of the cardboard 20 to be lower than the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer 10, it becomes possible to bond the spunbond nonwoven fabric layer 10 and the cardboard 20 (laminate layer 21) using the same type of material (polylactic acid resin), which was previously considered difficult, while the spunbond nonwoven fabric layer 10 is not damaged and maintains its function as a filter. Furthermore, since the drip bag 100 is made primarily from polylactic acid resin, it greatly contributes to reducing the environmental burden when it is disposed of after use.

[0034] <Second Embodiment> Figure 2 is a schematic cross-sectional view showing the laminated structure of an extraction bag according to a second embodiment of the present invention. This extraction bag is used as a coffee drip bag 200, which is made by laminating a spunbond nonwoven fabric layer 10 and a meltblown nonwoven fabric layer 15, and joining a cardboard sheet 20 to this laminate. The drip bag 200 according to the second embodiment is the same as the drip bag 100 according to the first embodiment, but with a meltblown nonwoven fabric layer 15 added on top of the spunbond nonwoven fabric layer 10. Therefore, in the following sections, only the meltblown nonwoven fabric layer 15 will be described, and detailed explanations of the configuration similar to that of the drip bag 100 according to the first embodiment will be omitted.

[0035] [Meltblown nonwoven fabric layer] The meltblown nonwoven fabric layer 15 functions as a layer that prevents leakage of adhesive and contents during bag making. The meltblown nonwoven fabric layer 15 is formed by blowing a high-temperature, high-speed gas stream onto molten resin extruded from a spinning nozzle, stretching the molten resin, causing it to fibrously scatter, and then accumulating it on a collector to solidify it into a sheet. In the drip bag 200 according to the second embodiment, it is preferable that polylactic acid resin, a biodegradable resin, is used as the resin constituting the meltblown nonwoven fabric layer 15, similar to the spunbond nonwoven fabric layer 10. By ensuring that all nonwoven fabric layers contain polylactic acid resin in this way, the environmental impact of the drip bag 200 as a whole is reduced, while the laminated structure of the spunbond nonwoven fabric layer 10 and the meltblown nonwoven fabric layer 15 provides excellent filtering functionality. The basis weight of the meltblown nonwoven fabric layer 15 is 1 to 10 g / m². 2 It is preferable to use 6-10 g / m 2 This is preferable.

[0036] The degree of crystallinity of the polylactic acid resin contained in the meltblown nonwoven fabric layer 15 is not particularly limited, but it is known to be lower than that of the polylactic acid resin contained in the spunbond nonwoven fabric layer 10. For example, if the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer 10 is set to 30-60% as described above, the degree of crystallinity of the polylactic acid resin contained in the meltblown nonwoven fabric layer 15 will be 20-40%. In this case, if the laminate of the meltblown nonwoven fabric layer 15 and the spunbond nonwoven fabric layer 10 is folded and heated so that the meltblown nonwoven fabric layer 15 is on the inside, the meltblown nonwoven fabric layer 15 will function as an adhesive, making it easy to manufacture bags.

[0037] <Third Embodiment> Figure 3 is a schematic cross-sectional view showing the laminated structure of an extraction bag according to the third embodiment of the present invention. This extraction bag is used as a tea bag 300, which is formed by joining a spunbond nonwoven fabric layer 10 with a tag 30 as an accessory component. In addition, in this third embodiment of the tea bag 300, it is also possible to adopt a configuration in which a meltblown nonwoven fabric layer 15 is laminated on top of the spunbond nonwoven fabric layer 10, as in the drip bag 200 of the second embodiment. The tea bag 300 of the third embodiment is the same as the drip bag 100 of the first embodiment, but with a tag 30 instead of cardboard 20. Therefore, in the following sections, only the tag 30 will be described, and a detailed explanation of the configuration which is the same as that of the drip bag 100 of the first embodiment will be omitted.

[0038] [tag] Tag 30 is a component that is pinched with the fingers when suspending the tea bag 300 by string. When not in use, it is attached to the surface of the bag and peeled off when in use. The weight of the tag is 50-150g / m². 2 It is preferable to do so.

[0039] The tag 30 is provided with a laminate layer 31 on at least the surface in contact with the spunbond nonwoven fabric layer 10, on which a laminate material mainly composed of a thermoplastic resin is applied. In the tea bag 300 according to the third embodiment, polylactic acid resin, which is a biodegradable resin, is used as the resin for forming the laminate layer 31, similar to the spunbond nonwoven fabric layer 10. The thickness of the laminate layer 31 is preferably 10 to 80 μm, and more preferably 40 to 80 μm.

[0040] The degree of crystallinity of the polylactic acid resin contained in the laminate layer 31 of the tag 30 is set to be lower than the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer 10. For example, the degree of crystallinity of the polylactic acid resin contained in the laminate layer 31 is set to 1-20%, and the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer 10 is set to 30-60%. Here, it is preferable that the difference between the degree of crystallinity of the polylactic acid resin contained in the laminate layer 31 and the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer 10 is set to 10% or more. In this case, the polylactic acid resin contained in the laminate layer 31 of the tag 30 is easily softened, while the polylactic acid resin contained in the spunbond nonwoven fabric layer 10 is not easily softened, so that the tag 30 can be bonded to the spunbond nonwoven fabric layer 10 with appropriate adhesive strength. As a result, the tag 30 does not fall off when the tea bag 300 is filled with the extract, and there is no risk of damaging the tea bag 300 when peeling the tag 30 off the tea bag 300 during use.

[0041] [Manufacturing method for extraction bags (sheets for extraction bags)] The extraction bag (extraction bag sheet) of the present invention can be manufactured, for example, using a heated nip roll. Note that the heated nip roll is a conventionally known manufacturing apparatus and is therefore not shown in the illustration.

[0042] In the first embodiment, when manufacturing a drip bag 100, a cardboard 20 having a laminate layer 21 formed by extrusion lamination is laminated onto a spunbond nonwoven fabric layer 10, and this laminate is passed through a pair of heated nip rolls. In the second embodiment, when manufacturing a drip bag 200, a meltblown nonwoven fabric layer 15 is formed on a spunbond nonwoven fabric layer 10, and then a cardboard 20 having a laminate layer 21 formed by extrusion lamination is laminated on the side of the spunbond nonwoven fabric layer 10, and this laminate is passed through a pair of heated nip rolls. In the third embodiment, when manufacturing a tea bag 300, a tag 30 having a laminate layer 31 formed by dry lamination is laminated onto a spunbond nonwoven fabric layer 10, and this laminate is passed through a pair of heated nip rolls.

[0043] Here, if the heating temperature of the heated nip roll is set to a temperature higher than the glass transition temperature Tg of the polylactic acid resin (for example, Tg + 30°C to 100°C), then, for example, in the drip bag 100 according to the first embodiment, when the laminate passes through a pair of heated nip rolls, the polylactic acid resin contained in the laminate layer 21 on the surface of the cardboard 20 softens and bites into the gaps of the spunbond nonwoven fabric layer 10, thereby integrating and joining the spunbond nonwoven fabric layer 10 and the cardboard 20. At this time, the polylactic acid resin contained in the spunbond nonwoven fabric layer 10 has not yet softened at the temperature at which the polylactic acid resin contained in the laminate layer 21 softens, so the spunbond nonwoven fabric layer 10 is not damaged and can maintain its function as a filter. In the drip bag 200 according to the second embodiment and the tea bag 300 according to the third embodiment, the spunbond nonwoven fabric layer 10 and the cardboard 20 or tag 30 can be joined by utilizing a similar phenomenon.

[0044] The pair of heated nip rolls used in the manufacturing method of the extraction bag (extraction bag sheet) of the present invention may be a combination of two flat rolls, but one may be an embossed roll and the other a flat roll. [Examples]

[0045] Hereinafter, examples of the extraction bag of the present invention will be described. However, the present invention is not limited to the following examples.

[0046] An extraction bag (Examples 1 to 14) having the characteristic configuration of the present invention and an extraction bag (Comparative Examples 1 and 2) not having the characteristic configuration of the present invention were each produced and evaluated.

[0047] [Crystallinity (%)] A test piece was collected from the non-woven fabric, and the test piece was set in a differential scanning calorimeter (DSC) (manufactured by TA INSTRUMENTS, product number 2920MDSC V2.6A). Thereafter, the temperature was raised to 240 ° C at a rate of 10 ° C / min, and the crystallization heat generation amount ΔHc and the crystal melting heat amount ΔHm were measured. Then, the crystallinity of the non-woven fabric was calculated based on the above formula (1).

[0048] [Basis weight (g / m 2 )] In accordance with "JIS L 1913 General Test Methods for Non-Woven Fabrics", a 10 cm square test piece was collected from the non-woven fabric, the mass was measured, and the basis weight of the non-woven fabric was calculated.

[0049] [Evaluation] The state of the extraction bag after the heat-sealing treatment was visually evaluated according to the following criteria. Good: The spunbond non-woven fabric layer is not damaged and the paperboard is joined. Poor: The spunbond non-woven fabric layer is damaged or the paperboard is not joined.

[0050] <Example 1> As shown in FIG. 1, on a spunbond non-woven fabric (basis weight: 15 g / m 2 ) containing a polylactic acid resin having a crystallinity of 50%, a paperboard (basis weight: 200 g / m 2The extraction bag of Example 1 was prepared by laminating the sheets and passing them through a heated nip roll as a heat sealing treatment. The heat sealing treatment was performed at a temperature of 110°C and a pressure of 0.5 MPa for 0.5 seconds. The laminate layer was formed by extrusion lamination, in which a fluid polylactic acid resin was extruded onto a cardboard sheet. A polylactic acid resin with a crystallinity of 3% was used. Although the extraction bag of Example 1 is actually an extraction bag sheet before it is made into a bag, the material properties themselves do not change, so it was evaluated as an extraction bag.

[0051] <Examples 2-14, Comparative Examples 1-2> The extraction bags for Examples 2-14 and Comparative Examples 1-2 were prepared in the same manner as the extraction bag for Example 1, except that they were configured to have the configuration shown in Table 1. In the extraction bags for Examples 9-11, a meltblown nonwoven fabric layer was laminated on top of a spunbond nonwoven fabric layer, as shown in Figure 2. In addition, in the extraction bags for Examples 13 and 14 and Comparative Examples 1-2, a laminate layer was formed by dry lamination, which involves bonding stretched polylactic acid film.

[0052] Table 1 shows the composition of the extraction bags for Examples 1 to 14 and Comparative Examples 1 to 2, as well as the evaluation results.

[0053] [Table 1]

[0054] In Examples 1 to 14, the extraction bags, in which the degree of crystallinity of the polylactic acid resin contained in the laminate layer was set lower than that of the polylactic acid resin contained in the spunbond nonwoven fabric layer, were all able to undergo heat sealing without damaging the spunbond nonwoven fabric layer. Furthermore, in the extraction bags of Examples 1 to 14, only the polylactic acid resin contained in the laminate layer of the low-crystallinity cardboard softened, and the softened laminate layer intersected between the fibers of the spunbond nonwoven fabric layer, resulting in the cardboard being firmly bonded to the spunbond nonwoven fabric layer, and the cardboard and spunbond nonwoven fabric layer becoming one integrated unit.

[0055] In contrast, in Comparative Example 1, where the heat-seal temperature was set to 130°C and the degree of crystallinity of the polylactic acid resin in the laminate layer was set to be equal to that of the polylactic acid resin in the spunbond nonwoven fabric layer (i.e., the degree of crystallinity of the polylactic acid resin in the laminate layer was not set to be lower than that of the polylactic acid resin in the spunbond nonwoven fabric layer), the resin in the laminate layer did not soften, and the spunbond nonwoven fabric layer and the cardboard were not bonded. Furthermore, in Comparative Example 2, which had the same configuration as the extraction bag in Comparative Example 1, but with the heat-seal temperature set to 150°C, the polylactic acid resin in the laminate layer softened, but the fibers in the spunbond nonwoven fabric layer also softened, resulting in damage to the spunbond nonwoven fabric layer. [Industrial applicability]

[0056] The extraction bag and extraction bag sheet of the present invention can be used as drip bags for brewing coffee or tea bags for brewing tea, but can also be used as dashi packs for brewing dashi from bonito, kelp, etc. Furthermore, the manufacturing method of the extraction bag and extraction bag sheet of the present invention can be used to manufacture filters for each of the above applications. [Explanation of Symbols]

[0057] 10. Spunbond nonwoven fabric layer 15 Meltblown nonwoven fabric layer 20 Cardboard (accessory components) 21 Laminating layer 30 Tags (attached parts) 31 Laminating layer 100 Drip Bags (Extraction Bags) 200 Drip Bags (Extraction Bags) 300 tea bags (brewing bags)

Claims

[Claim 1] An extraction bag comprising a spunbond nonwoven fabric layer containing polylactic acid resin and an attached component, A laminate layer containing polylactic acid resin is provided on at least the surface of the accessory member that is in contact with the spunbond nonwoven fabric layer. An extraction bag in which the degree of crystallinity of the polylactic acid resin contained in the laminate layer is set to be lower than the degree of crystallinity of the polylactic acid resin contained in the spunbond nonwoven fabric layer.

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