Pull-out bag

Abstract

To provide a high-added-value extraction bag that has the functionality and strength required for an extraction bag and is also considerate of the effects on the environment and the human body. [Solution] The extraction bag 1 is formed of a film 10 of plant-derived biomass plastic and has a plurality of holes 11. The film is a biaxially stretched film stretched in the MD direction and the TD direction, and has a MD tensile strength of 20 MPa to 50 MPa, a TD tensile strength of 20 MPa to 50 MPa, and an open area ratio of 4% to 35%.

Description

[Technical field]

[0001] The present disclosure relates to an extraction bag. [Background technology]

[0002] Background of the Invention Paper, nonwoven fabric, net-like, and film-like materials are used as extraction bags for dried leaves and stems of black tea, Japanese tea, medicinal herbs, and the like, as well as their crushed products. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-337935 A Summary of the Invention

[0004] In recent years, the selection of extraction bags made of biodegradable materials has been increasing from the viewpoint of the impact on the environment and the human body. Therefore, there is a demand for extraction bags with high added value that have the functionality and strength required for an extraction bag and also take into consideration the impact on the environment and the human body.

[0005] The disclosed technology is an extraction bag having a plurality of holes, which is made of a plant-derived biomass plastic film. The film is a biaxially stretched film stretched in the MD and TD directions, and has a MD tensile strength of 20 MPa to 50 MPa, a TD tensile strength of 20 MPa to 50 MPa, and a pore area ratio of 4% to 35%.

[0006] Further details will be described in the following embodiments. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an external view showing one embodiment of an extraction bag. [Diagram 2] FIG. 2 is an enlarged view of a film having a plurality of holes formed therein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] <1. Overview of the extraction bag> (1) The extraction bag according to the embodiment may be an extraction bag formed of a film of biomass plastic derived from plants and having a plurality of holes. The film may be a biaxially stretched film stretched in the MD and TD directions, and may have a MD tensile strength of 20 MPa to 50 MPa, a TD tensile strength of 20 MPa to 50 MPa, and a porosity of 4% to 35%. In this case, an extraction bag with high added value that can function as an extraction bag while being considerate of the effects on the environment and the human body can be obtained.

[0009] (2) The film may further have a MD heat shrinkage rate of 2% to 5% and a TD heat shrinkage rate of 0% to 2.5%. In this case, the extraction bag can achieve both processability during hole formation and extractability with hot water.

[0010] (3) The film has a thickness of 15 μm to 30 μm, an average pore size of 150 μm to 500 μm, and a pore size of 1×10 -3 In this case, an extraction bag having workability and extractability can be obtained.

[0011] (4) The film may have a static friction coefficient of 0.6 or less, which provides a processable extraction bag.

[0012] (5) The film may be made of a polylactic acid resin.

[0013] (6) The film may be made of a cellulose-based resin.

[0014] (7) The extraction bag may be an extraction bag for a beverage.

[0015] <2. Example of extraction bag> Hereinafter, the embodiments will be described in more detail with reference to the drawings.

[0016] The extraction bag is a bag filled with tea leaves for black tea, Japanese tea, Chinese tea, herbal tea, herbal tea, soup stock ingredients, or coffee beans, and is intended to extract ingredients from the filled materials.

[0017] The extraction bag is an extraction bag 1 formed of a biomass film 10 (film 10) formed in a tetrahedral shape (pyramid shape) consisting of four faces such as an equilateral triangle, as shown in Fig. 1. The extraction bag 1 has a plurality of holes 11 almost evenly (without bias) over the entire surface. In the following description, a film having holes will be referred to as a "perforated film", and a film without holes will be simply referred to as a "film".

[0018] The film is made of biomass plastic derived from plants. Specifically, the film contains polylactic acid resin or cellulose resin. The polylactic acid resin is made of, for example, corn, sugarcane, potatoes, and grains. The cellulose resin is made of, for example, wood and cotton. Examples of the cellulose film include cellophane and cellulose acetate films.

[0019] The film is preferably a biodegradable plastic made of 100% polylactic acid, which is particularly biodegradable. Such biodegradable plastics are highly transparent, and the contents can be clearly seen from the outside of the extraction bag, so that, for example, in the case of a product in which the process of extracting ingredients while observing the state of the contents is enjoyed, the added value of the extraction bag can be improved. Note that the film may be substantially made of 100% polylactic acid, and may contain, for example, about 0.5% by mass of an antistatic agent.

[0020] The film is a biaxially stretched film stretched in the machine direction (MD) and transverse direction (TD). By using a biaxially stretched film, the film can have the strength required for an extraction bag having a hole.

[0021] Specifically, perforated films have lower strength than unperforated films. When perforated films are filled with a filling material, a tensile force acts on the film to a certain extent. Therefore, the decrease in strength may lead to damage to the film. In contrast, biaxially oriented films have higher strength than other manufacturing methods (for example, casting methods that do not involve a stretching step), and are suitable as films for extraction bags.

[0022] The holes may be formed by any method, such as by melting and perforating the film in a non-contact state (melt perforation), by penetrating a heated punch pin into the film to perforate it, or by perforating with a laser.

[0023] The holes may be holes 11 aligned in the MD and TD directions on the film 10 as shown in Fig. 2(a). Alternatively, the holes may be holes 11 aligned in one of the MD and TD directions on the film 10 but not aligned in the other of the MD and TD directions, that is, arranged in a so-called staggered pattern as shown in Fig. 2(b).

[0024] Each hole has a hole diameter designed so that the filling of the extraction bag does not flow out of the bag during transportation, storage, and extraction after filling. The hole diameter is designed according to the filling, and preferably has an average hole diameter of, for example, 150 μm to 500 μm. If it is less than 150 μm, it may be difficult to perforate and may cause defective holes. Also, if it is less than 150 μm, the extraction speed of the filling may not be obtained, and extraction may take a long time.

[0025] The perforated film preferably has an opening rate of 4% to 35%. If it exceeds 35%, the tensile strength of the perforated film is not obtained, and the workability of the extraction bag is reduced during the formation of the extraction bag or during the filling of the filling material, and there is a risk of tearing. If it is less than 4%, the extraction speed is not obtained, and the extraction may take a long time.

[0026] The above-mentioned hole diameter and porosity are 1×10 -3It is preferable that the film has a water permeability coefficient of at least cm / sec (based on JIS A 1218). This allows for water permeability almost equivalent to that of conventional paper or nonwoven fabric extraction bags, and suppresses the reduction in extraction time due to the use of a film.

[0027] The perforated film preferably has a MD tensile strength of 20 MPa to 50 MPa and a TD tensile strength of 20 MPa to 50 MPa. In addition, the unperforated film preferably has a MD tensile strength of 80 MPa to 200 MPa and a TD tensile strength of 80 MPa to 200 MPa. Here, the tensile strength is measured in accordance with JIS K 7127 (ISO 527-3).

[0028] The perforated film preferably has a MD heat shrinkage rate of 2% to 5% and a TD heat shrinkage rate of 0% to 2.5%. A lower heat shrinkage rate is preferable, but if the MD heat shrinkage rate is 2% or less, the workability decreases when forming holes using heat. Here, the heat shrinkage rate is obtained by measuring the dimensions before heating and the dimensions after maintaining in a 100°C incubator for 15 minutes, and calculating the shrinkage rate.

[0029] In addition, the biaxially oriented film is also advantageous in that it provides higher heat resistance (lower heat shrinkage) than other manufacturing methods. That is, when the contents of the extraction bag are extracted with hot water, if the extraction bag shrinks due to heat, the contents will stick together inside the extraction bag, which may result in insufficient extraction. Therefore, a biaxially oriented film is suitable as a film for the extraction bag.

[0030] From the viewpoint of workability during processing of the extraction bag and during filling with the filling material, the film preferably has a certain degree of flexibility and smoothness.

[0031] From the viewpoint of smoothness, the front and back surfaces of the perforated film preferably have a static friction coefficient of 0.6 or less. When the static friction coefficient is 0.6 or less, smoothness is obtained and the manufacturing equipment can be reduced when processing the extraction bag. Reducing the amount of catching reduces the occurrence of wrinkles and deformations in the extraction bag, improving the yield rate and reducing interruptions to the manufacturing equipment. Therefore, the front and back surfaces of the perforated film preferably have a static friction coefficient of 0.6 or less. Here, the static friction coefficient is measured in accordance with JIS P 8147.

[0032] The film (the portion of the perforated film where no holes are formed) preferably has a thickness of 15 μm to 30 μm. If the thickness is less than 15 μm, the perforated film may be damaged during processes such as perforation and formation of the extraction bag, or during extraction by the user. If the thickness exceeds 30 μm, the processability and handleability may be reduced.

[0033] Such a perforated film is used to form, for example, an extraction bag 1 as shown in Figure 1. The extraction bag is formed by joining the edges in a desired shape, for example by heat sealing.

[0034] If the film is difficult to heat seal, a two-layer structure may be formed by providing an adhesive layer mainly made of polyvinylidene chloride resin (PVDC) on one side of the film. The film is then processed into a desired shape, and the extraction bag is obtained by heat sealing at the adhesive layer. The film may also contain a modifier to improve heat adhesion. Polybutylene succinate (PBS) or the like may be used as the modifier. EXAMPLES

[0035] A perforated film having a plurality of holes formed therein was obtained under the conditions shown below. Also, an extraction bag filled with a filling material was obtained under the conditions shown below.

[0036] <Unperforated film> Raw material: Polylactic acid resin 100% by weight Thickness: 20μm MD tensile strength: 142MPa TD direction tensile strength: 140MPa

[0037] <Perforated film> MD tensile strength: 29.1MPa TD direction tensile strength: 27.3MPa Drilling method: Melt drilling Average pore size: 400μm Open area rate: 8% Permeability coefficient: 3.4×10 -3 cm / sec Static friction coefficient: 0.34

[0038] <Filled extraction bag> Filling: black tea leaves Extraction bag shape: Pyramid type (see Figure 1)

[0039] The extraction bag thus formed did not suffer from wrinkles, deformation of the bag, or breakage of the film due to the film getting caught on the manufacturing equipment during production, and the manufacturing equipment did not experience any stoppage.

[0040] The filled extraction bag was placed in a cup filled with hot water and extraction was performed. The pyramid shape of the extraction bag was maintained, the black tea leaves were fully opened inside the extraction bag, and fragrant black tea was extracted. It was also confirmed that the smell of the film did not transfer to the black tea. [Explanation of symbols]

[0041] 1:Extraction bag 10: Biomass film (film) 11: Hole

Claims

1. An extraction bag formed of a plant-derived biomass plastic film and having a plurality of holes, The film is A biaxially oriented film stretched in the MD and TD directions, 20MPa〜50MPa MD tensile strength, 20MPa〜50MPa TD tensile strength, 4%〜35% hole ratio, extraction bag.

2. The film further has a MD heat shrinkage of 2% to 5% and a TD heat shrinkage of 0% to 2.5%.

2. The extraction bag according to claim 1.

3. The film is A thickness of 15 μm to 30 μm; An average pore size of 150 μm to 500 μm; 1x10 -3 A hydraulic conductivity of 1000 mm / s or more; 2. The extraction bag of claim 1, comprising:

4. The film is having a static friction coefficient of 0.6 or less; 2. The extraction bag according to claim 1.

5. The film is made of a polylactic acid resin.

2. The extraction bag according to claim 1.

6. The film is made of a cellulose-based resin.

2. The extraction bag according to claim 1.

7. The extraction bag according to claim 1 , wherein the extraction bag is a beverage extraction bag.

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