JP2017225589A - Coffee drip filter and coffee drip bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coffee drip filter for stably obtaining a delicious coffee extract.SOLUTION: A coffee drip filter 1 is made by embossing a non-woven fabric including a fiber formed of a hydrophobic resin. The filter 1 has an embossed part with an area rate of 30-80%, the embossed part with compressibility of 60-80% (wherein, the compressibility of the embossed part=(L0-L1)/L0. In the formula, L0 is a filter thickness of a non-embossed part, and L1 is a filter thickness of the embossed part), a basis weight of 20-55 g/m, and permeability of 10-30 cm/cm/second. Alternatively, the filter 1 has a product of the area rate and the compressibility of the embossed part of 25-55%, a basis weight of 20-55 g/m, and permeability of 10-30 cm/cm/second.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a coffee drip bag that can be easily put in a drip manner by being hooked on an upper part of a container such as a cup, and a coffee drip filter used for the coffee drip bag.

  As a drip bag that allows you to easily put a cup of coffee in a drip system, a bag body made of a water-permeable filterable sheet is filled with coffee powder, and a holder made of a paperboard sheet on the side of the bag body Attached ones are widespread. There are various types of such drip bags, but roughly divided, the in-cup type bag body is set in the middle of the cup during coffee extraction, and most of the bag body is immersed in the extract ( Patent Document 1) can be divided into an on-cup type (Patent Document 2) in which the bag body is set on the top of the cup and the bag body is not immersed in the extract or only partially immersed in the extract. .

  Of these, the on-cup type is expected to obtain a coffee extract that is closer to the original paper drip method than the in-cup type and has an excellent taste and aroma.

  On the other hand, the deliciousness of the coffee extract largely depends on the type of coffee powder, the particle size, how the coffee is added, etc., but also depends on the time taken for coffee extraction. In this regard, those who have expertise can take the steaming process by adjusting the pouring speed when extracting coffee with a drip bag, but it is difficult for ordinary people. In particular, in the on-cup type drip bag, the extraction is completed until the hot water poured into the bag body oozes out from the bag body, so that the taste of the coffee extract greatly changes depending on the pouring speed. In addition, in the in-cup type drip bag, the deliciousness of the coffee extract finally obtained by the coffee extract extracted until the liquid level in the bag body and the liquid level in the cup substantially coincide. Therefore, it is necessary to adjust the pouring speed to make the coffee delicious.

  On the other hand, in order to ensure an appropriate steaming time for ordinary people and to make coffee with excellent taste and fragrance, a filter for coffee drip is formed from two layers of laminated nonwoven fabrics with different hydrophobicities, and their basis weight It has been proposed that the amount be in a specific range (Patent Document 3).

In addition, in order to efficiently extract components during coffee extraction, the coffee extraction filter has a laminated structure of an ultrafine continuous fiber nonwoven fabric layer with an average fiber diameter of 2 to 5 μm and a support layer, and both layers are heat-sealed such as hot embossing. When compounding by the method, the fusion area ratio should be 40% or less from the viewpoint of ensuring filtration performance, and the air permeability should be 10 to 200 cm ³ / cm ² / sec in order to sufficiently extract taste components from coffee powder. Has been proposed (Patent Document 4).

Japanese Patent No. 4079041 Japanese Patent No. 5326366 Japanese Patent No. 3675486 JP 2005-342207 A

  However, if the filter used in the drip bag is increased in basis weight of the hydrophobic fiber or the fusion area ratio (that is, the area ratio of the embossed part by embossing) is adjusted to 40% or less, the drip bag The deliciousness of the coffee extract obtained in (1) still largely depends on the rate of pouring water into the drip bag. Therefore, when a general person puts coffee without paying special attention to the pouring speed, the taste of the coffee extract changes depending on the occasion.

  In addition, in the coffee drip bag product form, the bag body is filled with coffee powder, and the coffee powder is packed in contact with the filter forming the bag body, so that the coffee can be stored while the drip bag is being stored. The surface active component contained in the powder adheres to the filter forming the bag body. For this reason, the speed at which the coffee extract oozes out the bag body after storage is increased after storage, and a delicious coffee extract cannot be stably obtained in this respect as well.

  On the other hand, the present invention provides a drip bag even when a bag body of a drip bag manufactured using a coffee drip filter is filled with coffee powder and packaged in a state where the filter and coffee powder are in contact with each other. Providing a coffee drip filter that allows the general public to stably obtain a coffee extract that has the original taste of coffee by allowing the poured water to ooze out of the bag body over time. And providing a coffee drip bag using the coffee drip filter.

In the case of using a non-woven fabric as a filter in the specific coffee extraction form called a coffee drip bag, the present inventor has a filter air permeability of 10 to 30 cm ³ / cm so that delicious coffee can be stably extracted. It is preferable to form it at ² / sec. For this purpose, embossing is applied to the non-woven fabric forming the filter, and both the area ratio of the embossed part and the compression ratio of the embossed part are within a specific range, or the product of these products. The present invention has been conceived by finding that it is effective to set a specific range.

That is, the present invention is a coffee drip filter in which a nonwoven fabric containing fibers formed of a hydrophobic resin is embossed,
The area ratio of the embossed part in the filter is 30-80%,
Compression rate of embossed part is 60-80%
(However, the compression ratio of the embossed portion = (L0−L1) / L0
In the formula, L0 is the filter thickness of the non-embossed part
L1 is the thickness of the embossed filter)
The basis weight is 20 to 55 g / m ² ,
Provided is a coffee drip filter having an air permeability of 10 to 30 cm ³ / cm ² / sec.

  Moreover, in this invention, it replaces with prescribing | regulating the area ratio 30-80% of an embossing part, and the compression rate 60-60% of an embossing part in the filter for the above-mentioned coffee drip, and these products are 25-55%. To provide a filter for coffee drip.

  In addition, the present invention is a coffee drip bag formed of the above-described coffee drip filter and having a bag body filled with coffee powder and a holder made of a thin plate material and attached to the bag body. Thus, the holder provides a coffee drip bag having a latching portion for latching the holder on the top of the cup.

According to the coffee drip filter of the present invention, the air permeability of the filter is 10 to 30 cm ³ / cm by setting the area ratio and the compression ratio of the embossed part to a specific range, or by setting these products to a specific range. ^Since it is adjusted to ² / second, when this filter is used as a drip bag filter, it becomes possible for ordinary people to stabilize the coffee extract having the original taste of coffee.

FIG. 1 is a schematic plan view and a cross-sectional view of a coffee drip filter according to an embodiment. FIG. 2 is a scanning electron micrograph of a cross section of the embossed portion. FIG. 3 is a relationship diagram between the flavor evaluation of the coffee extract and the air permeability of the filter. FIG. 4 is a diagram showing the relationship between the extraction time required to obtain a coffee extract from 140 mL of hot water and the air permeability of the filter. FIG. 5A is a relationship diagram between the compressibility of the embossed portion of the filter and the air permeability of the filter. FIG. 5B is a relationship diagram between the compression ratio of the embossed portion of the filter and the air permeability of the filter, in which the scale of the vertical axis in FIG. 5A is changed. FIG. 6A is a relationship diagram between the area ratio of the embossed portion of the filter and the air permeability of the filter. FIG. 6B is a relationship diagram between the area ratio of the embossed portion of the filter and the air permeability of the filter, in which the scale of the vertical axis in FIG. 6A is changed. FIG. 7 is a relationship diagram between the product (%) of the area ratio of the embossed portion and the compression ratio of the embossed portion, and the air permeability. FIG. 8 is a relationship diagram between extraction time and air permeability in an in-cup type drip bag. FIG. 9A is a relationship diagram between the number of storage days and the extraction time in drip bags having different embossed area ratios. FIG. 9B is a relationship diagram between the number of storage days and the extraction time in drip bags having different embossed area ratios. FIG. 9C is a relationship diagram between the number of storage days and the extraction time in drip bags having different embossed area ratios.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In each figure, the same numerals indicate the same or equivalent components.

<Overview>
FIG. 1 is a schematic plan view and a cross-sectional view of a coffee drip filter 1 according to an embodiment of the present invention.

This coffee drip filter 1 is obtained by embossing a nonwoven fabric 2 containing fibers formed of a hydrophobic resin, and the area ratio of the embossed portion so that the air permeability is 10 to 30 cm ³ / cm ² / sec. And the compression ratio is limited to a predetermined range. That is, the present inventor repeats the extraction test in the coffee drip bag using various coffee powders and various non-woven fabric filters, so that the coffee extract having the original taste of coffee in the drip bag is stable even for the general public. In order to ensure that the hot water poured into the drip bag is allowed to bleed out of the bag body over a sufficient period of time, the air permeability of the filter should be 10-30 cm ³ / cm. It was found that ² / sec is effective (FIG. 3). Therefore, in the present invention, the area ratio and the compression ratio of the embossed portion of the nonwoven fabric are adjusted so as to achieve this air permeability. More specifically, the area ratio and the compression ratio of the embossed part are set in specific ranges (FIGS. 5A, 5B, 6A, and 6B), or the product of the area ratio and the compression ratio of the embossed part is specified. (FIG. 7).

  The air permeability is approximately 60 to 100 seconds when 8 g of finely ground coffee powder is put into a bag body (75 mm × 90 mm) of a coffee drip bag and 140 mL of hot water is poured by the method shown in the embodiment. This corresponds to the liquid permeability of the filter that completes the extraction.

  In the present invention, the flow rate is not defined as the characteristic value of the filter, but the air permeability is defined for the following reason. That is, when a coffee drip filter is formed using water-repellent fibers (Patent Document 3), water does not contain a surface active component unlike a coffee extract. The rate at which water passes through the filter is very slow. Therefore, the water flow rate cannot be used as an index of the coffee extract liquid flow rate. In addition, the flow rate of the coffee extract greatly depends not only on the measurement method and measurement conditions, but also on the composition of the coffee extract and the standardization thereof is difficult. Therefore, in the present invention, air permeability is used as a characteristic value of a filter for making delicious coffee.

In the present invention, the air permeability represents the air permeability of JIS L1096 air permeability A method (method using a Frazier type air permeability tester). This air permeability is obtained by measuring the air resistance (R = kPa · sec / m) of the test piece with an air permeability tester (KES-F8, manufactured by Kato Tech Co., Ltd.) and converting the air resistance by the following formula. Can be sought.
Air permeability (cm ³ / cm ² /sec)=12.5/R

<Nonwoven fabric>
In the embodiment shown in FIG. 1, a laminated nonwoven fabric of a melt blown nonwoven fabric 3 and a wet nonwoven fabric 4 is used as the nonwoven fabric 2.

  Among these, the melt blown nonwoven fabric 3 is preferably formed of an olefinic hydrophobic resin selected from polypropylene, polyethylene, ethylene propylene copolymer and the like.

The preferred fiber diameter of the melt blown nonwoven fabric 3 is 0.3 to 10 μm, and the preferred basis weight is 5 to 25 g / m ² . By including the melt blown nonwoven fabric 3 formed of a hydrophobic resin in the nonwoven fabric 2, the nonwoven fabric 2 can be used as a water-repellent filter, and the coffee extract passes through the nonwoven fabric when poured into the coffee drip filter 1. It is possible to lengthen the time until the start of brewing and to secure the steaming time of the coffee powder. And once liquid flow starts, since the surface active component contained in the coffee extract is adsorbed by the melt blown nonwoven fabric 3, moderate liquid permeability can be obtained.

In the present invention, a spunbond nonwoven fabric having a fiber diameter of 5 to 10 μm and a basis weight of 10 to 25 g / m ² may be used instead of the melt blown nonwoven fabric 3. This spunbond nonwoven fabric is also preferably made of an olefinic hydrophobic resin. From the viewpoint of reducing the fiber diameter and making it easy to control the air permeability, it is preferable to provide a melt blown nonwoven fabric rather than a spunbonded nonwoven fabric.

  On the other hand, the wet nonwoven fabric 4 is a nonwoven fabric having a lower content of hydrophobic fibers than the melt blown nonwoven fabric 3 or the spunbond nonwoven fabric. More specifically, the wet nonwoven fabric 4 is made of an olefinic hydrophobic resin such as polypropylene, polyethylene, or an ethylenepropylene copolymer, a hydrophilic fiber such as polyester or rayon, a natural fiber such as pulp or Manila hemp, or a mixed fiber thereof. Can be formed. The content of hydrophobic fibers in the wet nonwoven fabric 4 is preferably 50% by mass or less, more preferably 15 to 25% by mass.

The preferred fiber diameter of the wet nonwoven fabric 4 is 10 to 30 μm, and the preferred fiber length is 2 to 10 mm.
Moreover, the preferable fabric weight of the wet nonwoven fabric 4 is 15-30 g / m < ² >. By including such a wet nonwoven fabric 4 in the nonwoven fabric 2, it can be prevented that an excessively long time is required for the coffee extract to pass through the nonwoven fabric 2.

  In this invention, it may replace with the wet nonwoven fabric 4, and may use the dry nonwoven fabric formed from core sheath fibers, such as polyester, polyethylene, a polypropylene. It is preferable to use a wet nonwoven fabric from the viewpoint that it is easy to impart an appropriate air permeability.

Nonwoven 2 overall basis weight, and coffee fine powder collecting performance, air permeability, cost, and 20~55g / m ² in terms of non-woven fabric strength and the like, preferably 25~40g / m ^2.

<Embossing>
In the embossing, the non-woven fabric 2 is thermocompression bonded using an embossing roll having irregularities on the surface so that the embossed portion 5 in which the non-woven fabric 2 is partially heat-sealed is distributed substantially uniformly throughout the non-woven fabric 2. This is a process for forming the nonwoven fabric 2 and giving the nonwoven fabric 2 strength. This embossing may be performed by facing an embossing roll having surface irregularities and a flat roll having a flat surface and passing a non-woven fabric between them, and a pair of embossing rolls having surface irregularities fitting each other are opposed to each other. You may go.

As shown in the scanning electron micrograph of FIG. 2, in the embossed portion 5, the fibers constituting the nonwoven fabric 2 are thermally fused according to the embossing strength to form a film. The present invention pays attention to the fact that the air permeability or liquid permeability of the coffee drip filter 1 varies depending on the degree of film formation in the embossed portion 5, and the coffee drip filter 1 has an air permeability of 10 to 30 cm ³ / cm ² / sec. In order to provide a degree, the area ratio of the embossed part 5 is 30 to 80%, preferably 40 to 80%, and the compression ratio of the embossed part is 60 to 80%, preferably 65 to 80%. That is, by setting the area ratio of the embossed portion 5 to 30 to 80% (FIGS. 6A and 6B) and the compression ratio to 60 to 80% (FIGS. 5A and 5B) as shown in the examples described later, It becomes easy to adjust the air permeability of the filter 1 for coffee drip to the range of 10 to 30 cm ³ / cm ² / sec, and in particular, the area ratio is 40 to 80% and the compression ratio is 65 to 80%. Therefore, as shown by the broken line in FIG. 5B, the air permeability does not depend on the compression rate, and is constant and stable for each predetermined area rate, so even if there is some variation in the compression rate of the embossed part in the product, The air permeability can be adjusted to 10 to 30 cm ³ / cm ² / sec.

  Here, the area ratio of the embossed part 5 is a ratio of the total area of the plurality of embossed parts 5 to the total area in the plan view of the filter, and can be calculated from a microscope image. The area of each embossed part 5 corresponds to the area of the top surface of the convex part of the embossing roll.

  The compression ratio of the embossed portion 5 is calculated from the filter thickness L1 at the thinnest portion of the embossed portion 5 and the filter thickness L0 at the substantially central portion of the adjacent non-embossed portion 6 by the above-described formula. , L0 can be measured by taking a cross-sectional image of the filter with an electron microscope.

In the coffee drip filter of the present invention, as shown in FIG. 7, the product of the area ratio of the embossed part 5 and the compression ratio of the embossed part 5 and the air permeability show a high correlation, and the area of the embossed part When the product of the rate and the compression ratio of the embossed portion is 25 to 55%, the air permeability is 10 to 30 cm ³ / cm ² / sec. As described above, the reason why the product of the area ratio of the embossed part 5 and the compressibility of the embossed part 5 and the air permeability has a high correlation is not necessarily clear, but the compressibility of the embossed part is not the film in the embossed part. This is presumed to be closely related to the area ratio of the converted region.

  Therefore, in the coffee drip filter of the present invention, the area ratio of the embossed portion is 30 to 80% and the compression ratio of the embossed portion is 60 to 80%, or the area ratio of the embossed portion 5 is When the product of the embossed portion 5 and the compression ratio is 25 to 55%, it can be said that the filmed area of the filter is increased as compared with the conventional coffee drip filter.

  On the other hand, if the area ratio of the embossed portion is excessively increased, the air permeability becomes too low, and it takes time for extraction, which makes the drip bag user-friendly. If the area ratio of the embossed portion is too small, the air permeability becomes too high, so that a sufficient extraction time cannot be obtained. Further, if the compression ratio of the embossed portion is excessively increased, pinholes are easily formed in the embossed portion 5 and the desired air permeability cannot be achieved. The desired air permeability cannot be achieved because the part is not sufficiently formed into a film, and the strength as a filter is insufficient. When the nonwoven fabric 2 is a laminated nonwoven fabric, the laminated nonwoven fabrics are peeled off. It becomes easy to do.

When the area ratio and the compression ratio of the embossed part 5 are adjusted to the above range and the air permeability of the coffee drip filter is 10 to 30 cm ³ / cm ² / sec, the coffee drip filter is brought into contact with the coffee powder at room temperature. Even if it is stored for several months, the flow rate of the coffee extract in this filter does not change significantly before and after storage. In the embossed part 5 that has been made into a film, even if the surfactant component of the coffee powder is adsorbed there, it is difficult for the coffee extract to ooze through the gaps between the fibers, and the embossed part 5 inhibits the passage of the liquid. It is thought to function as a part to do. On the other hand, for example, even if the embossed area ratio is set to 28% and the air permeability is adjusted to 10 to 30 cm ³ / cm ² / sec according to the basis weight, the coffee drip filter is kept in contact with coffee powder for several months at room temperature. Then, in the embossed part 5 that has not been sufficiently formed into a film, the surface active component of the coffee powder is adsorbed on the part of the embossed part that is not formed into a film, and the coffee extract oozes out in the same manner as the fiber gap in the non-embossed part. Therefore, the flow rate of coffee changes greatly, and the desired extraction time cannot be maintained.

  In addition, as a method of forming the embossed portion 5 of the coffee drip filter at a predetermined compression rate, the embossing temperature, pressure, and embossing roll processing speed are determined according to the type of resin constituting the nonwoven fabric 2, the fiber diameter, and the like. (Heating residence time), the shape of the embossed part, etc. may be adjusted as appropriate.

  There is no restriction | limiting in particular in the planar shape of each embossing part 5, It can be set as polygons, such as a circle and a rectangle. Further, the size of each embossed portion 5 is determined by the embossed portion from the viewpoint of the ease of processing of the embossed roll and the stability of the extraction time of the individual drip bag made of the nonwoven fabric produced by the embossed roll. When the shape is a circle, the diameter is preferably 0.2 to 3.0 mm.

  The embossed portions 5 in the coffee drip filter 1 may be dispersed in such a manner that the embossed portions 5 are formed substantially evenly over the entire filter. For example, the embossed portions 5 are arranged in a staggered arrangement (hexagonal lattice), a lattice arrangement (square lattice), or the like. Can be arranged.

<Coffee drip bag>
The coffee drip bag of the present invention has a bag body formed of the coffee drip filter of the present invention and a holder formed of a thin plate material and attached to the bag body. The interior of the bag body is filled with coffee powder. Further, the holder has a latching portion so that the holder can be latched on the upper part of the cup.

  There is no restriction | limiting in particular about the specific form of a holder, For example, it can be the same as that of the drip bag of the above-mentioned patent documents 1, 2. FIG.

Hereinafter, based on an Example, this invention is demonstrated concretely.
Test Examples 1 to 24 (flavor evaluation and air permeability)
(1) Outline of the test In order to investigate the relationship between the air permeability of various filters and the flavor of the coffee extract extracted using the filters, wet nonwoven fabrics having the following specifications were manufactured with the basis weight shown in Table 1, A melt blown nonwoven fabric (fiber diameter 6.0 μm) (PP-MB nonwoven fabric) made of polypropylene resin was laminated thereon with the basis weight shown in Table 1, and the laminate of the base layer nonwoven fabric and the melt blown nonwoven fabric was embossed. In this embossing, by adjusting the embossing temperature, pressure, speed, etc., the area ratio of the embossed part, the thickness of the non-embossed part, the thickness of the embossed part, the embossed compressibility, and the air permeability are shown in Table 1. A filter was obtained. In this case, the area ratio of the embossed part, the thickness of the non-embossed part, the thickness of the embossed part, the compressibility of the embossed part, and the air permeability were measured by the methods described below.

  A drip bag is manufactured as described below using the filter of each test example, the manufactured drip bag is vacuum-packed and stored at room temperature for 7 days, and coffee is extracted from 140 mL of hot water using the drip bag after storage. A liquid was obtained, and the extraction time required to obtain this extract and the flavor of the obtained coffee extract were evaluated. Details of these methods are described below. The results are shown in Table 1. Moreover, the relationship between flavor evaluation and air permeability is shown in FIG. 3, and the relationship between extraction time and air permeability is shown in FIG. 3 and 4, the test examples within the scope of the present invention are shown as examples, and the test examples outside the scope of the present invention are displayed as comparative examples.

Wet nonwoven fabric:
Fiber forming resin ... Mixed fiber of polyethylene terephthalate fiber and polyolefin fiber Fiber diameter ... 22μm
Fiber length ... 5mm

  The fiber diameter was calculated by visually observing the test piece with a digital microscope (manufactured by KEYENCE, VHX-5000), measuring five points, and taking the average.

The basis weight of the nonwoven fabric or the filter was calculated by taking a test piece of a certain area, measuring its mass, and converting it to a weight per 1 m ² .

(2) The area ratio of the embossed part The area ratio of the embossed part is determined by observing the surface of the filter used as a test piece with a digital microscope (VHX-5000, manufactured by KEYENCE Inc.). The following equation was calculated from the area S1 of the quadrilateral formed by connecting the centers of gravity and the areas S2 of the four embossed parts included in the quadrilateral (see FIG. 1).
Embossed area ratio (%) = S2 × 100 / S1

(3) Thickness of the non-embossed part, thickness of the embossed part, and compression ratio of the embossed part The cross-sectional image of the filter used as a test piece was magnified 400 times using a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation). , Measure the filter thickness (L1) of the embossed part and the filter thickness (L0) of the non-embossed part,
Compression ratio of embossed part (%) = (L0−L1) × 100 / L0
Was calculated.

(4) Air permeability The air resistance (R = kPa · sec / m) of the filter used as a test piece is measured with an air permeability tester (KES-F8, manufactured by Kato Tech Co., Ltd.). Obtained by conversion.
Air permeability (cm ³ / cm ² /sec)=12.5/R

(5) Manufacture and storage of drip bags First, on-cup type coffee drip bags were produced with the following specifications using the filters of each test example.

On-cup type drip bag specifications:
Bag body: Flat bag (75 mm x 90 mm) formed with the filter of each Example and Comparative Example
Holder: On-cup type holder substantially the same as FIG. 1 of Japanese Patent No. 5326366

Next, the bag body of the drip bag was filled with 8 g of finely ground coffee powder.
The drip bag filled with coffee powder was vacuum packaged and stored at room temperature for 7 days.

(6) Extraction of coffee About the drip bag after storage, 140 mL (90 ° C) of hot water is poured into the drip bag in several times, and the time from the start of pouring until the extraction is completed when the hot water has dropped from the drip bag ( Seconds) and measured as the extraction time. In this case, as a pouring method, first, 10 to 20 mL of hot water is poured, and after 10 seconds of steaming, the remaining hot water is poured to the bulk of the bag body of the drip bag up to the eighth to ninth minutes. When the surface is lowered, hot water is added, and by repeating this, all hot water is poured. After that, when the dropping interval of the extraction liquid dripping from the drip bag becomes 4 to 5 seconds, the extraction completion time is set. .

(7) Flavor Evaluation At the development laboratory of Ajinomoto General Foods Co., Ltd., which develops, researches and manufactures coffee drip bags, it is trained in flavor evaluation, certified as a flavor evaluator, and upgraded regularly. Six expert panels of flavor evaluation who passed the session became evaluators, and each of the coffee extracts obtained in (6) was divided into 9 stages from evaluation point 1 (low preference) to evaluation point 9 (high preference) Evaluated. The average of the evaluation points by six expert panels was used as the evaluation value for the flavor evaluation of each drip bag.
In this flavor evaluation, an evaluation score of 6.5 or higher is desirable.

FIG. 3 shows that the air permeability of the filter is preferably 10 to 30 cm ³ / cm ² / sec in order to obtain a taste evaluation value of 6.5 or more.

From FIG. 4, it can be seen that, according to the filter having an air permeability of 10 to 30 cm ³ / cm ² / sec, the extraction time for obtaining 140 mL of coffee extract is approximately 60 to 100 seconds.

Examples 1-16, Comparative Examples 1-6
(1) Manufacture of filter for coffee drip In the same manner as in Test Example 1, a wet nonwoven fabric is manufactured with the basis weight shown in Tables 2 to 5, and a melt blown nonwoven fabric made of polypropylene resin with the basis weight shown in Tables 2 to 5 thereon. (Fiber diameter 6.0 μm) (PP-MB nonwoven fabric) is laminated, embossed on a laminate of wet nonwoven fabric and melt blown nonwoven fabric, the area ratio of the embossed part, the thickness of the non-embossed part, the thickness of the embossed part, Filters with emboss compression ratios shown in Tables 2 to 5 were obtained. However, in Example 16, instead of the wet nonwoven fabric, a dry nonwoven fabric having the following specifications was manufactured and laminated with the melt blown nonwoven fabric.

Dry nonwoven fabric:
Fiber forming resin: Polyethylene terephthalate and modified polyester core-sheath structure fiber Fiber diameter: 10 μm
Fiber length ... 51mm

(2) Measurement of area ratio of embossed part, etc. For the filters of each Example and Comparative Example, the area ratio of the embossed part, the thickness of the non-embossed part, the thickness of the embossed part, the compressibility of the embossed part, the air permeability, and The extraction time (vacuum packaging, normal temperature, after storage for 7 days) for obtaining 140 mL of coffee extract was measured in the same manner as in Test Examples 1-24. Moreover, the product of the area ratio of the embossed part and the compression rate of the embossed part was calculated.
The results are shown in Tables 2-5.

  For the filters of Examples 1, 4, 6, 8 and Comparative Examples 1-6, an in-cup type drip bag having the following specifications was also produced, and extraction required to obtain a coffee extract from 140 mL of hot water by the following method. Time was measured. The results are shown in Table 6.

In-cup type drip bag specifications:
Bag body: Flat bag (70 mm x 90 mm) formed with the filter of each Example and Comparative Example
Holder: In-cup type holder substantially the same as FIG. 1 of Japanese Patent No. 4079041

Extraction time for in-cup drip bag:
Pour 10 cc of 140 mL of hot water (90 ° C.) and steam for 10 seconds, then pour the remaining hot water to the extent that it does not overflow from the bag, pour 10 mL of hot water when all is poured, and allow 10 seconds of steaming After that, pour the remaining hot water up to the 8th to 9th minute of the bag body of the drip bag, add hot water when the hot water level drops, and pour all hot water by repeating this, then inside the bag body After the liquid level of the cup coincides with the liquid level of the cup, the drip bag is pulled up from the liquid level and held so that the lower end of the drip bag is positioned on the opening surface of the cup. The time when the time became 4 to 5 seconds was defined as the extraction completion time, and the time from the start of pouring to the completion of extraction was defined as the extraction time for the in-cup type drip bag. Note that this in-cup type coffee extraction method is a convenient method for measuring the extraction time, and is not necessarily an extraction method in actual use.

From the above-mentioned Tables 2 to 5, it can be seen that the extraction time is approximately 60 to 100 seconds at an air permeability of 10 to 30 cm ³ / cm ² / sec in the range of a total basis weight of 20 to 55 g / m ² . In addition, it can be seen that the dry nonwoven fabric also has an air permeability of 10 to 30 cm ³ / cm ² / second and an extraction time of about 60 to 100 seconds.

(3) The compression ratio of the embossed part and the air permeability of the filter The relationship between the compressibility of the embossed part and the air permeability of the filter in the examples and comparative examples in Tables 2 to 4 where the nonwoven fabric is the same is shown in FIGS. 5A and 5B. Show. From FIG. 5A and FIG. 5B, it is effective to set the compression ratio of the embossed part to 60 to 80% in order to set the air permeability of the filter to 10 to 30 cm ³ / cm ² / second, and the compression ratio is excessive. It can be seen that a pinhole occurs in the filter when the value is increased to a high value.

  In addition, as shown by the broken line in FIG. 5B, it can be seen that when the compression ratio of the embossed portion is 60 to 80%, the air permeability hardly depends on the compression ratio and becomes approximately constant for each predetermined area ratio.

(4) Area ratio of embossed portion and air permeability of filter FIGS. 6A and 6B show the relationship between the area ratio of the embossed portion and the air permeability of the filter of Examples and Comparative Examples in Tables 2 to 4 where the configuration of the nonwoven fabric is the same. Show. From FIG. 6A and FIG. 6B, it can be seen that it is effective to set the area ratio of the embossed portion to 30 to 80% in order to set the air permeability of the filter to 10 to 30 cm ³ / cm ² / sec.

(5) Product of area ratio of embossed portion and compressibility of embossed portion and air permeability Product of area ratio of embossed portion and embossed portion compressibility of examples and comparative examples in Tables 2 to 4 having the same nonwoven fabric configuration ( %) And the air permeability are shown in FIG.
FIG. 7 shows that the product (%) of the area ratio of the embossed portion and the compression ratio of the embossed portion and the air permeability have a high correlation.

(6) Extraction time in in-cup type drip bag The relationship between extraction time and air permeability in Table 6 is shown in FIG. FIG. 8 shows that not only the extraction time for the on-cup type drip bag but also the extraction time for the in-cup type drip bag correlates with the air permeability.

Examples 17-22, Comparative Examples 7-9
In the same manner as in Example 1, a wet nonwoven fabric shown in Table 7 was produced, and a melt blown nonwoven fabric (fiber diameter 6.0 μm) (PP-MB nonwoven fabric) made of polypropylene resin with a basis weight shown in Table 7 was laminated thereon, The laminate of the wet nonwoven fabric and the melt blown nonwoven fabric was embossed to obtain a filter having the area ratio of the embossed part, the thickness of the non-embossed part, the thickness of the embossed part, and the embossed compression ratio shown in Table 7.

  Test example of the area ratio of the embossed part of these nonwoven fabrics, the thickness of the non-embossed part, the thickness of the embossed part, the compressibility of the embossed part, the air permeability, and the extraction time for obtaining a coffee extract from 140 mL (90 ° C) of hot water It measured similarly to 1-14. However, the extraction time was measured both before and after storage of the drip bag (vacuum packaging, normal temperature, stored for 7 days).

  The results are shown in Table 7. Moreover, although the structure of a nonwoven fabric is equal, the intensity | strength of embossing differs (i) Comparative example 7, Example 17, Example 20, (ii) Comparative example 8, Example 18, Example 21, and (iii) 9A, 9B, and 9C show the relationship between the number of storage days and the extraction time for each of Comparative Example 9, Example 19, and Example 22.

  By comparing FIG. 9A, FIG. 9B, and FIG. 9C, as the basis weight of the nonwoven fabric is increased, the extraction time after storage is shortened compared to before storage, but the degree of shortening increases the degree of embossing. It has been eased. As a result, among these, the basis weight of the nonwoven fabric was the largest, but in Comparative Example 9 where the area ratio of the embossed portion was 28% and the compression ratio was 66%, the extraction time after storage was about 50 seconds, whereas the nonwoven fabric In Examples 17 and 20, in which the basis weight is minimal but the degree of embossing is stronger than that of Comparative Example 7, the extraction time exceeds 60 seconds even after storage. Therefore, it can be seen that controlling the extraction time by the embossing strength (area ratio, compression ratio) rather than the basis weight of the nonwoven fabric is more effective for stabilizing the extraction performance.

DESCRIPTION OF SYMBOLS 1 Filter for coffee drip 2 Nonwoven fabric 3 Melt blown nonwoven fabric 4 Wet nonwoven fabric 5 Embossed part 6 Non-embossed part

Claims (6)

A coffee drip filter in which a non-woven fabric containing fibers formed of a hydrophobic resin is embossed,
The area ratio of the embossed part in the filter is 30-80%,
Compression rate of embossed part is 60-80%
(However, the compression ratio of the embossed portion = (L0−L1) / L0
In the formula, L0 is the filter thickness of the non-embossed part
L1 is the thickness of the embossed filter)
The basis weight is 20 to 55 g / m ² ,
A filter for coffee drip having an air permeability of 10 to 30 cm ³ / cm ² / sec. A coffee drip filter in which a non-woven fabric containing fibers formed of a hydrophobic resin is embossed,
The product of the area ratio of the embossed part and the compression ratio of the embossed part in the filter is 25 to 55%.
(However, the compression ratio of the embossed portion = (L0−L1) / L0
In the formula, L0 is the filter thickness of the non-embossed part
L1 is the thickness of the embossed filter)
The basis weight is 20 to 55 g / m ² ,
A filter for coffee drip having an air permeability of 10 to 30 cm ³ / cm ² / sec.   The filter for coffee drip according to claim 1 or 2, wherein the area ratio of the embossed portion is 40 to 80%.   The filter for coffee drip according to any one of claims 1 to 3, wherein the embossed portion has a compression ratio of 65 to 80%.   A nonwoven fabric containing fibers formed of a hydrophobic resin is a melt blown nonwoven fabric or a spunbond nonwoven fabric formed of an olefinic hydrophobic resin, and a dry nonwoven fabric having a lower content of hydrophobic fibers than the meltblown nonwoven fabric or the spunbond nonwoven fabric, or It is a laminated nonwoven fabric with a wet nonwoven fabric, The filter for coffee drip in any one of Claims 1-4.   A coffee drip bag formed of the coffee drip filter according to any one of claims 1 to 5 and having a holder formed of a thin plate material and attached to the bag body, the bag body being filled with coffee powder. A coffee drip bag, wherein the holder has a latching portion for latching the holder on the top of the cup.

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