JP6949588B2 - Manufacturing method of non-woven fabric for extraction filter and non-woven fabric for extraction filter - Google Patents

Description

The present invention relates to a non-woven fabric for an extraction filter and a method for producing a non-woven fabric for an extraction filter, which can be particularly suitably used for an extraction filter for beverages and soup stock.

In recent years, the use of extraction bags has been expanding, and development of filter materials for food extraction, which is used by molding a porous sheet such as a non-woven fabric into a bag shape in beverages such as tea and coffee, and seasoning liquids such as dashi and broth. Is underway. Such a filter material for food extraction is required to have strength that can withstand the load of a water-containing object to be extracted.

As a conventional filter material, a web formed by depositing a core-sheath type composite fiber having a polyolefin-based polymer as a sheath component and a polyester-based polymer having a melting point higher than that of the sheath component by 50 ° C. or more as a core component is used. A technique for improving the heat-sealing property and strength of a liquid filter material by adopting a long-fiber non-woven fabric that is partially heat-press-welded is disclosed (see JP-A-2004-242944).

Japanese Unexamined Patent Publication No. 2004-242944

However, while the long-fiber non-woven fabric as in the above-mentioned prior art has high strength, it tends to have poor extractability. In addition, an extraction filter that extracts seasoning liquid components such as soup stock and broth for commercial use often exerts a force due to stirring of the seasoning liquid during use, so that it has particularly high strength and heat sealability. An extraction filter having excellent extractability is desired.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a non-woven fabric for an extraction filter having excellent strength, heat-sealing property and extractability, and a method for producing the same.

As a result of diligent studies to solve the above inconvenience, the present inventor has excellent strength, heat sealability and extractability by using a non-woven fabric in which specific fibers are combined in a specific range, and is a soup stock for business use. , And have found that it is possible to provide a non-woven fabric for an extraction filter suitable for an extraction filter for extracting a seasoning liquid component such as broth, and have completed the present invention.

The invention made to solve the above problems is a drawn polyester fiber having a fineness of 1.5 dtex or more and 2.0 dtex or less and an average fiber length of 7 mm or more and 20 mm or less, and a fineness of 1.0 dtex or more and 2.0 dtex or more. An undrawn polyester fiber having an average fiber length of 3 mm or more and 10 mm or less and a polyester core-sheath type composite having a fineness of 1.8 dtex or more and 2.5 dtex or less and an average fiber length of 3 mm or more and 10 mm or less. The content of the drawn polyester fiber is 15% by mass or more and 30% by mass or less, the content of the undrawn polyester fiber is 20% by mass or more and 35% by mass or less, and the polyester fiber is contained. It is a non-woven fabric for an extraction filter in which the content of the core-sheath type composite fiber is 15% by mass or more and 30% by mass or less.

The non-woven fabric for an extraction filter contains drawn polyester fibers, unstretched polyester fibers, and polyester core-sheath composite fibers having fineness, average fiber length, and content in the above ranges. Therefore, it can have excellent strength, heat sealability and extractability. The fineness (unit: dtex) is measured according to the general spun yarn test method of JIS-L1095 (2010).

It is preferable that the non-woven fabric for the extraction filter further contains a polypropylene-based core-sheath type composite fiber. The fineness of the polypropylene-based core-sheath composite fiber is preferably 1.0 dtex or more and 2.0 dtex or less, and the average fiber length is preferably 3 mm or more and 10 mm or less. The content of the polypropylene-based core-sheath composite fiber is preferably 20% by mass or more and 30% by mass or less. When the fineness, average fiber length and content of the polypropylene-based core-sheath composite fiber further contained in the non-woven fabric for the extraction filter are within the above ranges, the strength, heat sealability and extractability of the non-woven fabric for the extraction filter can be improved. It can be improved further.

The basis weight conforming to JIS-P8124 of the nonwoven fabric for the filter for extracting (2011), 15.0g / ^{m 2} or more 50.0 g / ^{m 2} or less. Further, the tear strength in the flow direction of the fibers in accordance with JIS-P8116 (2000) of the non-woven fabric for the extraction filter is preferably 1300 mN or more and 1600 mN or less, and the tear strength in the lateral direction orthogonal to the flow direction is 1400 mN. It is preferably 1700 mN or more and 1700 mN or less. When the basis weight and the tear strength of the non-woven fabric for extraction filter are within the above ranges, the strength, heat sealability and extractability of the non-woven fabric for extraction filter can be further improved. Here, the flow direction of the fibers refers to the papermaking direction (longitudinal direction) of the non-woven fabric, and the horizontal direction refers to the direction perpendicular to the papermaking direction of the non-woven fabric.

The tensile elongation at break in the flow direction in accordance with JIS-P8113 (2006) of the non-woven fabric for extraction filter is preferably 10% or more and 30% or less, and the tensile elongation at break in the lateral direction is 20% or more and 40%. The following is preferable. When the tensile elongation at break of the non-woven fabric for extraction filter is within the above range, the strength, heat sealability and extractability of the non-woven fabric for extraction filter can be further improved.

The air permeation resistance of the non-woven fabric for extraction filter in accordance with JIS-P8117 (2009) is preferably 0.3 seconds or more and 1.2 seconds or less. The measured value of the air permeation resistance in the present invention indicates the value when 20 sheets of the non-woven fabric for the extraction filter are stacked. When the air permeation resistance of the non-woven fabric for the extraction filter is within the above range, the extractability of the non-woven fabric for the extraction filter can be further improved.

Another invention made to solve the above problems is a drawn polyester fiber having a fineness of 1.5 dtex or more and 2.0 dtex or less and an average fiber length of 7 mm or more and 20 mm or less, and a fineness of 1.0 dtex or more 2 Unstretched polyester fiber with 0.0 dtex or less and average fiber length of 3 mm or more and 10 mm or less, and polyester core sheath with fineness of 1.8 dtex or more and 2.5 dtex or less and average fiber length of 3 mm or more and 10 mm or less. A step of wet-making the mold composite fiber and a step of calendar-processing the fiber sheet formed after the wet-making step are provided, and the content of the drawn polyester fiber is 15% by mass or more and 30% by mass or less. Production of non-woven fabric for extraction filter in which the content of the unstretched polyester fiber is 20% by mass or more and 35% by mass or less, and the content of the polyester core-sheath composite fiber is 15% by mass or more and 30% by mass or less. The method.

According to the method for producing a non-woven fabric for an extraction filter, a non-woven fabric for an extraction filter having excellent strength, heat sealability and extractability can be reliably produced.

According to the present invention, it is possible to provide a non-woven fabric for an extraction filter having excellent strength, heat sealability and extractability.

Hereinafter, the non-woven fabric for an extraction filter according to an embodiment of the present invention will be described in detail.

<Non-woven fabric for extraction filter>
The non-woven fabric for an extraction filter contains drawn polyester fibers, unstretched polyester fibers, and polyester core-sheath composite fibers. The drawn polyester fiber has a fineness of 1.5 dtex or more and 2.0 dtex or less, and an average fiber length of 7 mm or more and 20 mm or less. The undrawn polyester fiber has a fineness of 1.0 dtex or more and 2.0 dtex or less, and an average fiber length of 3 mm or more and 10 mm or less. Further, the polyester-based core-sheath type composite fiber has a fineness of 1.1 dtex or more and 2.5 dtex or less, and an average fiber length of 3 mm or more and 10 mm or less.

The content of the stretched polyester fiber in the non-woven fabric for the extraction filter is 15% by mass or more and 30% by mass or less, the content of the unstretched polyester fiber is 20% by mass or more and 35% by mass or less, and the polyester. The content of the core-sheath type composite fiber is 15% by mass or more and 35% by mass or less.

(Stretched polyester fiber)
The drawing in the drawn polyester fiber means a filament in which a spun undrawn yarn is stretched and wound by a drawing machine at several times the speed. The polyester resin constituting the drawn polyester fiber is basically a polycondensate of polyvalent carboxylic acid and polyalcohol. Specific examples of the polyester resin include polyethylene terephthalate, polyethylene naphthalate, polytributylene terephthalate, polybutylene naphthalate, polytrimethylene terephthalate, polylactic acid, polyhydroxybutyrate, polycaprolactone, and polybutylene succinate. Be done. Examples of polylactic acid include a condensate of lactic acid units of either L-lactic acid or D-lactic acid, or a mixed condensate thereof. Since the non-woven fabric for the extraction filter contains drawn polyester fibers, the tensile elongation at break and the tear strength can be set in a good range. Of these, polyethylene terephthalate is preferable.

The softening point of the drawn polyester fiber is preferably 110 ° C. or higher and 140 ° C. or lower. The crystallinity of the unstretched polyester fiber is preferably 10% or more and 40% or less. When the softening point and the crystallinity of the drawn polyester fiber are within the above ranges, an appropriate tensile elongation at break can be obtained, so that the extractability and the piercing strength can be improved.

The drawn polyester fiber may contain additives such as titanium oxide, and those modified by adding a modifying group to impart functionality such as improving hygroscopicity can also be used. The cross-sectional shape of the single fiber unit is not particularly limited as the drawn polyester fiber, and various irregular cross-sectional yarns typified by round, triangular, eight-leaf, flat, and Y-shaped can also be used. Further, as the drawn polyester fiber, a false twisted yarn obtained by subjecting these raw yarns to false twisting may be used.

The lower limit of the fineness of the drawn polyester fiber is 1.5 dtex, preferably 1.6 dtex, and more preferably 1.7 dtex. If the fineness is less than 1.5 dtex, sufficient tear strength may not be obtained. On the other hand, the upper limit of the fineness is 2.0 dtex, preferably 1.9 dtex, and more preferably 1.8 dtex. By setting the fineness in the above range, the tensile elongation at break and the tear strength can be set in a good range.

The lower limit of the average fiber length of the drawn polyester fiber is 7 mm, preferably 8 mm, and more preferably 9 mm. If the average fiber length is less than 7 mm, the tensile elongation at break and the tear strength may decrease. On the other hand, the upper limit of the average fiber length is 20 mm, preferably 15 mm, and more preferably 12 mm. If the average fiber length exceeds 20 mm, the texture of the non-woven fabric for the extraction filter becomes non-uniform, and as a result of increasing the air permeation resistance, the extractability may decrease.

The lower limit of the content of the drawn polyester fiber is 15% by mass or more, preferably 18% by mass, and more preferably 20% by mass. If the content is less than 15% by mass, the required tear strength may not be obtained. On the other hand, the upper limit of the content is 30% by mass, preferably 28% by mass, and more preferably 25% by mass. If the content exceeds 30% by mass, the texture of the non-woven fabric for the extraction filter becomes non-uniform, the air permeability resistance increases, and as a result, the extractability may decrease.

(Unstretched polyester fiber)
The undrawn yarn in the undrawn polyester fiber means a filament of the spun undrawn yarn. As the polyester resin constituting the unstretched polyester fiber, those mentioned in the stretched polyester fiber can be used. By containing the unstretched polyester fiber in the non-woven fabric for the extraction filter, the tensile elongation at break can be improved.

The softening point of the unstretched polyester fiber is preferably 110 ° C. or higher and 140 ° C. or lower. The crystallinity of the unstretched polyester fiber is preferably 10% or less. When the softening point and the crystallinity of the unstretched polyester fiber are within the above ranges, the tear strength can be increased.

The lower limit of the fineness of the undrawn polyester fiber is 1.0 dtex, preferably 1.2 dtex, and more preferably 1.3 dtex. On the other hand, as the upper limit of the fineness, 2.0 dtex is preferable, 1.8 dtex is more preferable, and 1.5 dtex is further preferable. When the fineness is in the above range, the tensile elongation at break can be set in a good range.

The lower limit of the average fiber length of the undrawn polyester fiber is 3 mm, preferably 3.5 mm, and more preferably 4 mm. If the average fiber length is less than 3 mm, the tensile elongation at break may decrease. On the other hand, the upper limit of the average fiber length is 10 mm, more preferably 8 mm, still more preferably 7 mm. If the average fiber length exceeds 10 mm, the tensile elongation at break may become higher than necessary.

The lower limit of the content of the unstretched polyester fiber is 20% by mass, preferably 22% by mass, and more preferably 25% by mass. If the content is less than 20% by mass, the tensile elongation at break may decrease. On the other hand, the upper limit of the content is 35% by mass, 30% by mass, and more preferably 28% by mass. If the content exceeds 35% by mass, the tensile elongation at break may be excessively improved.

(Polyester core-sheath composite fiber)
The polyester-based core-sheath type composite fiber refers to a fiber in which the fiber structure has a core-sheath structure, and the material of the core portion and the material of the sheath portion are polyester-based resins. As the polyester resin constituting the polyester core-sheath type composite fiber, the same polyester resin as the polyester resin constituting the unstretched polyester fiber can be used. The polyester-based core-sheath type composite fiber is, for example, modified polyethylene terephthalate in which the core material is polyethylene terephthalate and the sheath material is modified polyester resin such as low-melting polyethylene terephthalate to lower the melting point. Examples include fibers having a core-sheath structure. Examples of the modified polyethylene terephthalate include copolymerized polyethylene terephthalate. When only the stretched polyester fiber and the unstretched polyester fiber are contained, the heat fusion property at the time of the calendar process is low, so that the fusion between the fibers is weakened, and the strength and the air permeability resistance may be lowered. However, when the non-woven fabric for an extraction filter contains the polyester-based core-sheath type composite fiber, the fusion property between the fibers is improved, and the strength and the air permeability resistance can be improved.

The melting point of the sheath portion of the polyester core-sheath type composite fiber is preferably 100 ° C. or higher and 140 ° C. or lower, and the melting point of the core portion of the polyester-based core-sheath composite fiber is preferably 200 ° C. or higher and 250 ° C. or lower. When the melting points of the sheath portion and the core portion of the polyester-based core-sheath type composite fiber are in the above range, it is possible to improve the extractability while having an appropriate strength.

The lower limit of the fineness of the polyester core-sheath type composite fiber is 1.1 dtex, preferably 1.2 dtex, and more preferably 1.3 dtex. On the other hand, the upper limit of the fineness is 2.5 dtex, preferably 2.0 dtex, and more preferably 1.7 dtex. By setting the fineness in the above range, the heat-sealing property between the fibers can be improved.

The lower limit of the average fiber length of the polyester core-sheath type composite fiber is 3 mm, more preferably 3.5 mm, still more preferably 4 mm. If the average fiber length is less than 3 mm, the number of contacts for heat fusion is reduced, so that the fusion between fibers may be weakened. On the other hand, the upper limit of the average fiber length is 10 mm, preferably 8 mm, and more preferably 7 mm. If the average fiber length exceeds 10 mm, it may be difficult to heat-fuse the fibers.

The lower limit of the content of the polyester core-sheath type composite fiber is 15% by mass, more preferably 18% by mass, and more preferably 20% by mass. If the content is less than 15% by mass, the number of contacts for heat fusion is reduced, so that the fusion between fibers may be weakened. On the other hand, the upper limit of the content is 35% by mass, more preferably 28% by mass, still more preferably 25% by mass. If the content exceeds 30% by mass, it may be difficult to heat-seal the fibers.

(Polopropylene-based core-sheath composite fiber)
The polypropylene-based core-sheath type composite fiber refers to a fiber in which the fiber structure has a core-sheath structure, the core portion is made of polypropylene-based resin, and the sheath portion is also made of polypropylene-based resin. The polypropylene core-sheath type composite fiber has a core-sheath structure in which, for example, the core material is a polypropylene resin, and the sheath material is a low melting point polypropylene resin whose melting point is lowered by modifying the polyester resin. Examples include fiber. The heat-sealing property can be further improved by further containing the polypropylene-based core-sheath type composite fiber in the non-woven fabric for the extraction filter.

The melting point of the sheath portion of the polypropylene-based core-sheath composite fiber is preferably 130 ° C. or higher and 160 ° C. or lower, and the melting point of the core portion of the polypropylene-based core-sheath composite fiber is preferably 110 ° C. or higher and 150 ° C. or lower. As a result, the heat seal strength can be improved by using the polypropylene-based core-sheath type composite fiber.

As the lower limit of the fineness of the polypropylene-based core-sheath type composite fiber, 1.5 dtex is preferable, 1.8 dtex is more preferable, and 2.0 dtex is further preferable. On the other hand, as the upper limit of the fineness, 2.5 dtex is preferable, 2.4 dtex is more preferable, and 2.3 dtex is further preferable. When the fineness is in the above range, the heat sealability can be further improved.

As the lower limit of the average fiber length of the polypropylene-based core-sheath type composite fiber, 3 mm is preferable, 3.5 mm is more preferable, and 4 mm is further preferable. If the average fiber length is less than 3 mm, the heat seal strength may decrease. On the other hand, as the upper limit of the average fiber length, 10 mm is preferable, 8 mm is more preferable, and 6 mm is further preferable. When the average fiber length exceeds 10 mm, the heat-sealing property may be improved more than necessary, the non-woven fabric for the extraction filter may be strengthened, and the bag-making suitability may be deteriorated.

The lower limit of the content of the polypropylene-based core-sheath composite fiber is preferably 20% by mass, more preferably 22% by mass, and even more preferably 24% by mass. If the content is less than 20% by mass, the heat seal strength may decrease. On the other hand, the upper limit of the content of the non-woven fabric for the extraction filter is preferably 30% by mass, more preferably 28% by mass, and even more preferably 26% by mass. If the content exceeds 30% by mass, the heat-sealing property may be improved more than necessary, the non-woven fabric for the extraction filter may be strengthened, and the bag-making suitability may be deteriorated.

(Other ingredients, etc.)
In the non-woven fabric for an extraction filter, for example, pigments, surfactants, waxes, sizing agents, fillers, rust preventives, conductive agents, defoaming agents, dispersants, viscosity modifiers, coagulants, coagulants, and paper strength improvement Internal additives such as ingredients, yield improvers, paper dust dropout preventives, bulking agents, and thickeners can be added.

(Basis weight)
As the lower limit of the basis weight according to JIS-P8124 (2011) of the non-woven fabric for extraction filter, 15.0 g / m ² is preferable, 20.0 g / m ² is more preferable, and 25.0 g / m ² is further preferable. preferable. If the basis weight is ^{less than 15.0 g / m 2} , the required strength may not be obtained. On the other hand, the upper limit of the basis weight is preferably from 50.0 g / ^{m 2,} more preferably 45.0 g / ^{m 2,} more preferably 40.0 g / ^{m 2.} If the basis weight ^{exceeds 50.0 g / m 2} , the tensile elongation at break may be higher than required.

(Tear strength)
The tear strength in accordance with JIS-P8116 (2000) in the flow direction of the fibers of the non-woven fabric for extraction filter is preferably 1300 mN or more and 1600 mN or less. When the tear strength in the flow direction is within the above range, it is possible to suppress tearing during stirring when used as an extraction filter. The tear strength in the lateral direction, which is a direction orthogonal to the flow direction of the non-woven fabric for extraction filter, is preferably 1400 mN or more and 1700 mN or less. When the tear strength in the lateral direction is within the above range, it is possible to suppress tearing during stirring when used as an extraction filter.

Further, as the lower limit of the ratio (Y / T ratio) of the non-woven fabric for extraction filter to the longitudinal tear strength to the transverse tear strength, 90% is preferable, 95% is more preferable, and 100% is further preferable. On the other hand, the upper limit of the Y / T ratio is preferably 120%, more preferably 110%, and even more preferably 108%. By adjusting the Y / T ratio to the above range, the orientation ratios of the fibers in the longitudinal direction and the lateral direction can be brought close to substantially the same orientation. As a result, when the non-woven fabric for the extraction filter is used, the proof stress against shearing forces from various directions is improved, and tearing due to stirring during use can be suppressed.

(Tension breaking elongation)
As the lower limit of the tensile elongation at break in the flow direction of the non-woven fabric for extraction filter, 10% is preferable, 13% is more preferable, and 15% is further preferable. On the other hand, the upper limit of the tensile elongation at break in the flow direction is preferably 30%, more preferably 25%, and even more preferably 20%. By setting the tensile elongation at break in the flow direction within the above range, it is possible to improve the breaking resistance against shearing forces from various directions when the non-woven fabric for an extraction filter is used.

The lower limit of the tensile elongation at break in the lateral direction of the non-woven fabric for an extraction filter is preferably 20%, more preferably 22%, and even more preferably 24%. On the other hand, the upper limit of the tensile elongation at break in the lateral direction is preferably 40%, more preferably 35%, and even more preferably 30%. By setting the tensile elongation at break in the lateral direction within the above range, it is possible to improve the fracture resistance against shearing forces from various directions when the non-woven fabric for an extraction filter is used, similar to the tensile elongation at break in the flow direction. ..

(density)
The lower limit of the density of non-woven fabric for the filter for extracting, preferably 0.20 g / cm ^3, more preferably ^{0.22g / cm 3, 0.25g / cm} 3 is more preferred. If the density is ^{less than 0.20 g / cm 3} , the required tear strength may not be obtained. On the other hand, the upper limit of the density is preferably 0.50 g / cm ^3, more preferably ^{0.45g / cm 3, 0.40g / cm} 3 is more preferred. If the density exceeds 0.50 g / cm ³ , the tensile elongation at break may be higher than required. The density is measured in accordance with "Paper and Paperboard-Thickness, Density and Specific Volume Test Method" described in JIS-P8118 (2014). The density can be adjusted by, for example, the fineness, average fiber length, and content of the drawn polyester fiber, the undrawn polyester fiber, and the polyester core-sheath composite fiber, and can also be adjusted by setting the pressure in the calendar process. can. It is also possible to adjust these in combination.

(Standard deviation of paper thickness)
As the lower limit of the standard deviation (hereinafter, also referred to as the standard deviation) of the paper thickness of the non-woven fabric for extraction filter, 2.00 is preferable, 2.50 is more preferable, and 3.00 is further preferable. If the standard deviation is less than 2.00, the required extractability cannot be obtained.
On the other hand, as the upper limit of the standard deviation, 6.10 is preferable, 6.00 is more preferable, and 5.90 is further preferable. If the standard deviation exceeds 6.10, the required extractability cannot be obtained. The standard deviation is calculated from 10 measurements in accordance with "Paper and Paperboard-Thickness, Density and Specific Volume Test Methods" described in JIS-P8118 (2014). The standard deviation can be adjusted by, for example, the fineness, average fiber length, and content of drawn polyester fibers, undrawn polyester fibers, and polyester core-sheath composite fibers, and can also be adjusted by setting the pressure in the calendar process. Can be done. It is also possible to adjust these in combination.

(Air permeability resistance)
The lower limit of the air permeation resistance of the non-woven fabric for extraction filter in accordance with JIS-P8117 (2009) is preferably 0.30 seconds, more preferably 0.40 seconds, and even more preferably 0.50 seconds. If the air permeation resistance is less than 0.30 seconds, the non-woven fabric for the extraction filter will be clogged, and it will take time to extract the necessary components of the object to be extracted, which may cause a problem in practical use. There is. On the other hand, the upper limit of the air permeation resistance is preferably 0.80 seconds, more preferably 0.78 seconds, and even more preferably 0.75 seconds. If the air permeation resistance exceeds 0.80 seconds, clogging of the non-woven fabric for extraction filter is reduced, and there is a possibility that the necessary components of the object to be extracted cannot be extracted.

(Puncture strength)
The lower limit of the piercing strength (maximum stress until a glass needle rod with a diameter of 7 mm and a tip shape diameter of 7 mm penetrates) in accordance with JIS-Z1707 (1997) of the non-woven fabric for extraction filter is 6.0 N or more. Preferably, 6.5 N or more is more preferable, and 7.0 N or more is further preferable. If the piercing strength is less than 6.0 N, when it is used as an extraction filter, when it is stirred to extract the broth of the contents, the strength of the extraction filter is weak and there is a risk that it cannot be used due to tearing. be. On the other hand, the upper limit of the piercing strength is preferably 15.0 N or less, more preferably 14.0 N or less, still more preferably 13.0 N or less. If the upper limit of the piercing strength exceeds 15.0 N, when used as an extraction filter, the strength will increase, but the tensile elongation at break (length / width) will decrease, and there is a risk of breakage from minute holes. be.

(Heat seal strength)
250 N / m is preferable as the lower limit of the heat seal strength of the non-woven fabric for extraction filter measured under the conditions of ^{160 ° C. and pressure 1.0 kg / cm 2} and 2 seconds in accordance with JIS-Z0238 (1998). , 300 N / m is more preferable. If the heat seal strength is less than 250 N / m, the heat seal strength is not sufficient, and therefore, there is a possibility that bag making may be defective during bag making. On the other hand, the upper limit of the heat seal strength can be, for example, 1000 N / m. If the heat seal strength is less than 250 N / m, the required heat seal property cannot be obtained, and there is a possibility that the heat seal strength is not suitable for use as an extraction filter.

According to the non-woven fabric for an extraction filter, excellent strength, heat sealability and extractability can be provided. Therefore, it can be suitably used for an extraction filter for extracting seasoning liquid components such as commercial soup stock and broth, which are particularly required to have high strength and heat sealability.

<Manufacturing method of non-woven fabric for extraction filter>
The method for producing a non-woven fabric for an extraction filter includes a step of wet papermaking and a step of calendar processing the fiber sheet formed after the wet papermaking step.

(Papermaking process)
In this step, drawn polyester fibers having a fineness of 1.5 dtex or more and 2.0 dtex or less and an average fiber length of 7 mm or more and 20 mm or less, and a fineness of 1.0 dtex or more and 2.0 dtex or less and an average fiber length of 7 mm or more and 20 mm or less. Wet papermaking is performed on undrawn polyester fibers having a fineness of 3 mm or more and 10 mm or less and polyester core-sheath type composite fibers having a fineness of 1.1 dtex or more and 2.5 dtex or less and an average fiber length of 3 mm or more and 10 mm or less. Further, the content of the stretched polyester fiber in the non-woven fabric for the extraction filter is 15% by mass or more and 30% by mass or less, and the content of the unstretched polyester fiber is 20% by mass or more and 35% by mass or less. The content of the polyester-based core-sheath composite fiber is 15% by mass or more and 35% by mass or less. By the above-mentioned wet papermaking, a non-woven fabric for an extraction filter containing both fibers substantially uniformly can be obtained. Further, by wet-making the fiber components, it is possible to enhance the dispersibility of these components and enhance the uniformity and strength of the air permeability of the non-woven fabric for the extraction filter.

The wet papermaking method is not particularly limited, and examples thereof include known methods used in papermaking. Further, it may be a one-layer paper or a multi-layer paper with two or more layers.

The paper machine used for wet paper making is not particularly limited, and examples thereof include a circular net paper machine, a short net paper machine, a long net paper machine, and an inclined short net paper machine.

Among these, an inclined short net paper machine in which the Y / T ratio of fibers can be easily adjusted is preferable.

Papermaking can also be performed in the presence of a small amount of paper-making chemicals as long as the effects of the present invention are not impaired. The paper-making chemicals are not particularly limited, and for example, surfactants, waxes, sizing agents, fillers, rust preventives, conductive agents, defoaming agents, dispersants, viscosity modifiers, coagulants, coagulants, and paper strength improvement agents. Ingredients, yield improvers, paper dust dropout preventives, bulking agents, thickeners and the like can be mentioned.

(Calendar processing process)
In this step, the fiber sheet formed after the wet papermaking step is calendar-processed. By the calendering process, the adhesion between the fibers of the fiber sheet obtained in the papermaking process can be enhanced, an appropriate strength can be imparted to the non-woven fabric for the extraction filter, and the thickness can be made uniform.

The calendar processing equipment is not particularly limited, and examples thereof include a calendar device that combines a metal roll and a metal roll, a calendar device that combines a metal roll and a resin roll, and a calendar device that combines a metal roll and a cotton roll. Be done.

The lower limit of the heating temperature during calendar processing is not particularly limited, but is usually preferably 130 ° C., more preferably 140 ° C. The upper limit of the heating temperature during calendar processing is not particularly limited, but is usually preferably 170 ° C., more preferably 160 ° C. or lower. By setting the heating temperature within the above range, the uniformity of the thickness of the non-woven fabric for the extraction filter can be improved. If the heating temperature exceeds the upper limit, the fiber sheet melts, so that the air permeability may decrease and the smoothness may become too high. If the heating temperature is less than the above lower limit, unevenness may occur on the surface of the non-woven fabric for the extraction filter.

The upper limit of the linear pressure during calendar processing is not particularly limited, but is usually preferably 10 kg / cm, more preferably 20 kg / cm. The lower limit of the linear pressure during calendar processing is not particularly limited, but is usually preferably 100 kg / cm, more preferably 60 kg / cm. By setting the linear pressure within the above range, the uniformity of the thickness of the semipermeable membrane support can be improved. If the linear pressure exceeds the above upper limit, the bulkiness of the non-woven fabric for the extraction filter may be lost. If the linear pressure is less than the above lower limit, unevenness may occur on the surface of the non-woven fabric for the extraction filter.

According to the method for producing a non-woven fabric for an extraction filter, a non-woven fabric for an extraction filter having excellent strength, heat sealability and extractability can be reliably produced.

<Other Embodiments>
The present invention is not limited to the above embodiment, and can be implemented in various modifications and improvements in addition to the above embodiment.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

[Example 1]
A raw material for a fiber sheet was prepared from each of the following fiber components (1) to (4).
(1) 25% by mass of drawn polyester fiber having a fineness of 1.7 dtex, an average fiber length of 10.0 mm, a softening point of 130 ° C., and a crystallinity of 20%.
(2) 25% by mass of undrawn polyester fiber having a fineness of 1.4 dtex, an average fiber length of 5.0 mm, a softening point of 130 ° C., and a crystallinity of 5%.
(3) 25% by mass of polyester-based core-sheath composite fiber having a fineness of 1.4 dtex, an average fiber length of 5.0 mm, a core having a melting point of 220 ° C., and a sheath having a melting point of 130 ° C.
(4) 25% by mass of a polypropylene-based core-sheath composite fiber having a fineness of 2.2 dtex, an average fiber length of 5.0 mm, a core having a melting point of 160 ° C., and a sheath having a melting point of 140 ° C.

(Fineness)
The fineness (unit: dtex) of each of the above fiber components was measured in accordance with JIS-L1095 (2010) "General spun yarn test method".

(Average fiber length (number average fiber length))
For the average fiber length (unit: mm) of each of the above fibers, the number average fiber length was measured using a "Kayani FiberLab fiber length measuring machine" manufactured by Mezzo Automation.

(Other ingredients)
As other components, a thickener, a dispersant and an antifoaming agent were added.

First, in the papermaking process, the raw material of the fiber sheet was used to perform wet papermaking with an inclined short net paper machine to produce a fiber sheet. Next, in the drying step, the fiber sheet was dried using a dryer. Next, in the calendar processing step, the fiber sheet is calendar-processed under the conditions of a heating temperature of 150 ° C. and a linear pressure of 40 kg / cm using a calendar device combining a metal roll and a metal roll, and the extraction filter of Example 1 is processed. A non-woven fabric for use was obtained.

[Examples 2 to 12 and Comparative Examples 1 to 5]
Example 1 except that the fineness, average fiber length and content of the drawn polyester fiber, the undrawn polyester fiber, the polyester core-sheath composite fiber and the polypropylene core-sheath composite fiber are as shown in Table 1. In the same manner as above, the non-woven fabrics for extraction filters of Examples 2 to 12 and Comparative Examples 1 to 5 were obtained. In addition, "-" in Table 1 below indicates that the corresponding fiber was not used.

[evaluation]
Each of the obtained non-woven fabrics for extraction filters was evaluated by the following methods for each physical property value, durability during stirring, heat seal strength and extractability. The evaluation results are shown in Table 2.

[Basis weight (g / m ² )]
The measurement was performed in accordance with "Paper and Paperboard-Basis Weight Measuring Method" described in JIS-P8142 (1998).

[Paper thickness (μm)]
The paper thickness was measured according to "Paper and Paperboard-Test Method for Thickness, Density and Specific Volume" described in JIS-P8118 (2014). Further, as the standard deviation of the paper thickness, the standard deviation of the paper thickness of 10 samples was calculated.

[Density (g / cm ³ )]
The measurement was performed in accordance with "Paper and Paperboard-Thickness, Density and Specific Volume Test Method" described in JIS-P8118 (2014).

[Tear strength (mN) and Y / T ratio (%)]
The tear strength in the flow direction and the lateral direction of the fiber was measured according to JIS-P8116 (2000). From the measured value, the ratio (Y / T ratio) of the tear strength in the lateral direction to the tear strength in the flow direction was calculated.

[Tension breaking elongation (%)]
The measurement was performed according to JIS-P8113 (2006).

[Air permeation resistance (seconds)]
Twenty pieces of the obtained non-woven fabric for an extraction filter were stacked and measured according to JIS-P8117 (2009).

[Puncture strength (N)]
It is necessary to fix both ends of the obtained non-woven fabric for extraction filter to a shopper type testing machine compliant with JIS-P8114, and to break the non-woven fabric for extraction filter when the tip with a diameter of 7 mm is pierced with a spherical rod. The applied load was used as the piercing strength. The evaluation criteria for piercing strength were as follows.
Puncture strength of 7.0 N or more: When used as an extraction filter, there is no possibility of breakage during stirring, and it is suitable as an extraction filter.
Puncture strength less than 7.0N: When used as an extraction filter, it is highly likely to break during stirring and is not suitable as an extraction filter.

(Heat seal strength)
The obtained filter for extracting non-woven fabric by using JIS-Z-0238 (1998) in compliance with 160 ° C., and heat-sealed under a pressure of 1.0kg / ^cm 2, 2 seconds. Then, the heat seal strength of the obtained sample was measured.

(Extractability)
The extractability was evaluated by the following procedure.
(1) filled with coffee powder 8.0g into the obtained extract for non-woven fabric conforming to JIS-Z-0238 (1998) and 160 ° C., under a pressure 1.0kg / ^cm 2, 2 seconds Perform heat sealing.
(2) Put the coffee bag in a 200 ml beaker.
(3) Pour 160g of hot water into the beaker.
(4) 90 seconds after pouring hot water, the coffee bag was shaken 5 times to sample the coffee in the beaker.
(5) The coffee of the sample extracted by the above extraction method was evaluated by 10 evaluators according to the functionality evaluation analysis of JIS standard (JIS-Z9800). The sensuality of appearance was evaluated for the color strength of coffee, and the sensuality of flavor was evaluated for aroma and taste. The evaluator evaluated each item on a 5-point scale according to the following evaluation criteria, and the average of all evaluators was used as the evaluation result of each evaluation item. In addition, the average value of the evaluation items was used as the evaluation of extractability. The evaluation results were evaluated as ⊚ when the average value of the results of each item was 4.0 or more, ◯ when it was 3.5 or more, Δ when it was 3.0 or more, and × when it was less than 3.0. If the average value is 3.0 or more, it is considered that there is no problem in practical use, but if it is less than 3.0, it is considered that it is practically impossible.

As shown in Table 2 above, the non-woven fabric for an extraction filter of the present invention produced in Examples 1 to 12 was shown to be excellent in piercing strength, heat sealability and extractability.
On the other hand, Comparative Examples 1 to 5 were shown to be inferior in any of puncture strength, heat seal strength and extractability. In particular, Comparative Example 1 which does not contain drawn polyester fibers, Comparative Example 3 which does not contain polypropylene core-sheath composite fibers, Comparative Example 4 which does not contain polyester core-sheath composite fibers, and fineness of polyester core-sheath composite fibers. In Comparative Example 5, which had a low air permeability, the air permeability resistance was high and the extractability was very inferior. Further, Comparative Example 2 containing no undrawn polyester fiber was inferior in heat-sealing property and piercing strength.

The non-woven fabric for an extraction filter of the present invention has excellent strength, heat sealability and extractability. Therefore, it can be suitably used for an extraction filter for extracting seasoning liquid components such as commercial soup stock and broth, which are particularly required to have high strength and heat sealability.

Claims (6)

The fineness is 1.5 dtex or more and 2.0 dtex or less, and the average fiber length is 7 mm or more and 20 m.
Stretched polyester fibers of m or less and
The fineness is 1.0 dtex or more and 2.0 dtex or less, and the average fiber length is 3 mm or more and 10 m.
Unstretched polyester fiber of m or less and
The fineness is 1.1 dtex or more and 2.5 dtex or less, and the average fiber length is 3 mm or more and 10 m.
a polyester core-sheath composite yarn is m or less,
Containing polypropylene core-sheath type composite fiber,
JIS-P8124 (2011) basis weight conforming to is less than 15.0 g / ^{m 2} or more 40.0 g / ^{m 2,}
The density is 0.20 g / m ³ or more and 0.40 g / m ³ or less.
The content of the polypropylene-based core-sheath type composite fiber is 20% by mass or more and 30% by mass or less.
The content of the drawn polyester fiber is 15% by mass or more and 30% by mass or less.
The content of the unstretched polyester fiber is 20% by mass or more and 35% by mass or less.
A non-woven fabric for an extraction filter in which the content of the polyester-based core-sheath composite fiber is 15% by mass or more and 35% by mass or less. The polypropylene fineness of core-sheath composite yarn is at most 2.5dtex than 1.5 dtex, an average fiber length of Ri der least 10mm below 3 mm,
The non-woven fabric for an extraction filter according to claim 1, wherein the content of the polypropylene-based core-sheath type composite fiber is 25 % by mass. 2. The non-woven fabric for the extraction filter described. Claim that the tensile elongation at break in the flow direction of the fiber according to JIS-P8113 (2006) is 10% or more and 30% or less, and the tensile elongation at break in the lateral direction orthogonal to the flow direction is 20% or more and 40% or less. 1. The non-woven fabric for an extraction filter according to claim 2 or 3. The non-woven fabric for an extraction filter according to any one of claims 1 to 4, wherein the air permeability resistance according to JIS-P8117 (2009) is 0.30 or more and 0.80 seconds or less. A method for manufacturing a non-woven fabric for an extraction filter.
Stretched polyester fibers having a fineness of 1.5 dtex or more and 2.0 dtex or less and an average fiber length of 7 mm or more and 20 mm or less.
Unstretched polyester fibers having a fineness of 1.0 dtex or more and 2.0 dtex or less and an average fiber length of 3 mm or more and 10 mm or less.
Polyester core-sheath type composite fibers having a fineness of 1.1 dtex or more and 2.5 dtex or less and an average fiber length of 3 mm or more and 10 mm or less.
The process of wet papermaking with polypropylene core-sheath type composite fibers and
The fiber sheet formed after the wet papermaking process is provided with a calendar processing process.
The content of the polypropylene-based core-sheath type composite fiber is 20% by mass or more and 30% by mass or less.
The content of the drawn polyester fiber is 15% by mass or more and 30% by mass or less.
The content of the unstretched polyester fiber is 20% by mass or more and 35% by mass or less.
The polyester core-sheath type 35% by mass or less content of more than 15 wt% of the composite fiber is,
A JIS-P8124 basis weight of less than 15.0 g / ^{m 2} or more 40.0 g / ^{m 2} conforming to (2011) in the non-woven fabric for the filter for extracting a density of 0.20 g / ^{m 3} or more 0.40 g / m ³ der Ru manufacturing method of extracting non-woven fabric or less.