Organic acid containing drip sheet

Abstract

To provide an organic acid containing drip sheet capable of suppressing generation of bad odor due to decay of a drip and suppressing discoloration of food.SOLUTION: An organic acid containing drip sheet is a drip sheet used for storing food, and includes at least one absorbent sheet, the absorbent sheet contains an organic acid, the organic acid has a solubility in water at 30°C. of 0.3 g / 100 mL to 12 g / 100 mL, an organic acid content of the absorbent sheet is 0.03 g / m2 or more, the organic acid in the absorbent sheet is obtained by dissolving the organic acid in a solvent, the solvent is removed after contacting an organic acid solution of an organic acid concentration of which is less than saturation concentration with a substrate of the absorbent sheet.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a drip sheet used when storing foods such as meat and fish, and particularly relates to a drip sheet capable of preventing discoloration of foods.

Background Art

[0002] When selling foods such as fresh meat and fresh fish, the foods are placed in a resin tray and displayed in a packaged state where the opening surface of the tray is covered with a transparent wrapping film. Here, during display, fresh meat and fresh fish exude a red liquid called drip. Drip is a protein (myoglobin) component that leaks out of cells together with moisture through the cell membranes that were broken during freezing or non-freezing of meat and fish. If such drip accumulates at the bottom of the tray, it gives an unclean appearance and leads to a decrease in the willingness to purchase. Also, during transportation, there is a risk that the drip will flow out of the package and stain clothes and other items. Furthermore, if the drip rots inside the tray, it may have an adverse effect on the food or generate a bad odor.

[0003] To prevent problems related to such drip, when selling foods, a drip sheet is laid under the foods. By laying the drip sheet, the drip can be constantly absorbed to maintain a clean appearance, and the retention of drip at the bottom of the tray and leakage outside the package can also be prevented. Also, since the drip does not accumulate at the bottom of the tray due to the drip sheet, it does not reattach to the food, does not damage the food, and the freshness can be maintained for a long time.

[0004] As the drip sheet, for example, Patent Document 1 describes an absorbent sheet having at least three non-woven fabric layers of an upper layer, a middle layer, and a lower layer. The upper layer contains heat-adhesive fibers and an organic acid, the middle layer contains heat-adhesive fibers, pulp, and an organic acid, the lower layer contains heat-adhesive fibers and pulp, the upper layer has a larger fiber diameter of the heat-adhesive fibers than the middle layer and the lower layer, and a higher content of the organic acid than the middle layer, and the middle layer has a higher content of pulp than the lower layer (see Patent Document 1 (Claim 1)).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the absorption sheet described in Patent Document 1, when an organic acid is imparted to a nonwoven fabric, a solution in which not all of the organic acid is completely dissolved but only a part of the organic acid is dissolved and most of the organic acid is not dissolved (specifically, a fumaric acid dispersion with a concentration of 3% by mass) is used (see Patent Document 1 (paragraph 0044)). Therefore, the organic acid particles in the organic acid-containing liquid sprayed on the nonwoven fabric are likely to entangle and bond with the fibers in the upper layer, and most of them remain in the upper web before reaching the middle and lower layer webs (see Patent Document 1 (paragraph 0038)). However, since most of the organic acid is present in the upper web, the organic acid does not act on the drips absorbed in other parts, and the spoilage of the drips cannot be sufficiently suppressed. In addition, the organic acid imparted in such a manner is likely to fall off from the absorption sheet, and when the fallen organic acid adheres to food, there is a problem that the food discolors.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide an organic acid-containing drip sheet that can suppress the generation of bad odors due to the spoilage of drips and suppress the discoloration of food.

Means for Solving the Problems

[0008] The organic acid-containing drip sheet of the present invention is a drip sheet used when storing food, the drip sheet includes at least one layer of an absorption sheet, the absorption sheet contains an organic acid, the solubility of the organic acid in water at 30 ° C is 0.3 g / 100 mL to 12 g / 100 mL, and the content of the organic acid in the absorption sheet is 0.03 g / m 2The above is the case where an organic acid solution in which an organic acid is dissolved in a solvent and the concentration of the organic acid is less than the saturation concentration is brought into contact with the base material of the absorption sheet, and then the solvent is removed to be imparted.

[0009] Since the organic acid is applied to the entire thickness direction of the absorption sheet in the organic acid-containing drip sheet, the decay of the drip absorbed by the absorption sheet is suppressed, and the generation of a bad odor is suppressed. Further, since the solubility of the organic acid in water is low, it is suppressed that a large amount of the organic acid elutes into the unabsorbed drip and the acidity of the drip rapidly increases. Furthermore, since the organic acid is applied to the base material of the absorption sheet by a predetermined method, it is also suppressed that the organic acid drops off from the base material. Therefore, it is suppressed that the food comes into contact with a drip having a high acidity or the dropped organic acid and causes discoloration.

Advantages of the Invention

[0010] By using the organic acid-containing drip sheet of the present invention, it is possible to suppress the generation of a bad odor due to the decay of the drip and to suppress the discoloration of the food.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

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Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0012] The organic acid-containing drip sheet of the present invention is a drip sheet used when storing food. The drip sheet includes at least one layer of absorbent sheet, and the absorbent sheet contains an organic acid. The absorbent sheet has a function of absorbing and holding drips. Since this absorbent sheet contains an organic acid, the organic acid acts on the drips absorbed by the absorbent sheet, suppressing the spoilage of the drips and the generation of bad odors.

[0013] The organic acid has a solubility in water at 30 °C of 0.3 g / 100 mL or more, preferably 0.4 g / 100 mL or more, more preferably 0.5 g / 100 mL or more, and 12 g / 100 mL or less, preferably 11 g / 100 mL or less, more preferably 10.5 g / 100 mL or less. If the solubility of the organic acid in water at 30 °C is 0.3 g / 100 mL or more, the spoilage of the drips can be suppressed and the generation of bad odors can be suppressed. If it is 12 g / 100 mL or less, the influence of the organic acid on the food is reduced and the discoloration of the food can be suppressed. The solubility in water at 30 °C is the concentration of the organic acid in a saturated aqueous solution of the organic acid at a liquid temperature of 30 °C.

[0014] Specific examples of the organic acid include fumaric acid, succinic acid, adipic acid, sorbic acid, etc. Among these, as the organic acid, at least one selected from the group consisting of fumaric acid, adipic acid, and succinic acid is preferred.

[0015] The content of the organic acid in the absorbent sheet is preferably 0.03 g / m 2 or more, more preferably 0.04 g / m 2 or more, still more preferably 0.05 g / m2 or less, preferably 0.5 g / m 2 or less, more preferably 0.3 g / m 2 or less, still more preferably 0.2 g / m 2 or less, particularly preferably 0.1 g / m 2 or less. If the content of the organic acid is 0.03 g / m 2 or more, the spoilage of the drip can be suppressed and the generation of malodor can be suppressed. If it is 0.5 g / m 2 or less, the influence of the organic acid on the food becomes small and the discoloration of the food can be suppressed.

[0016] The organic acid in the absorption sheet is obtained by dissolving an organic acid in a solvent and contacting an organic acid solution having an organic acid concentration less than the saturation concentration with the base material of the absorption sheet, and then removing the solvent. By applying the organic acid by such a method, the organic acid penetrates into the interior of the water-absorbing fibers constituting the base material of the absorption sheet, and a film of the organic acid is formed on the surface of the synthetic resin fibers constituting the base material of the absorption sheet. As a result, the detachment of fumaric acid from the absorption sheet can be suppressed.

[0017] The base material of the absorption sheet is not particularly limited, and examples thereof include non-woven fabric, air-laid pulp, wet crepe paper, and tissue paper.

[0018] Examples of the non-woven fabric include a non-woven fabric composed only of water-absorbent fibers, a non-woven fabric composed of water-absorbent fibers and synthetic fibers, and a non-woven fabric obtained by hydrophilizing a non-woven fabric composed of synthetic fibers. The water-absorbent fibers are not particularly limited as long as they have water-absorbing properties. Note that water absorption means that liquid water (or a hydrophilic organic solvent) penetrates into the fibers by capillary action or the like. Examples of the water-absorbent fibers include cellulose fibers (pulp, cotton, hemp), rayon, and the like. Examples of the resin constituting the synthetic fibers include polyolefin resins, polyester resins, polyamide resins, and the like. The synthetic fibers may be fibers composed of a single material or composite fibers composed of multiple materials. Examples of the composite fibers include core-sheath type, parallel type, eccentric core-sheath type, radial type, hollow radial type, sea-island type, blend type, block type, and the like.

[0019] The type of non-woven fabric is not particularly limited, and examples include airlaid non-woven fabric, air-through non-woven fabric, spunlace non-woven fabric, spunbond non-woven fabric, and the like.

[0020] As the base material of the absorption sheet, an airlaid non-woven fabric obtained by the airlaid method is preferable, and particularly, an airlaid non-woven fabric composed of water-absorbent fibers and synthetic fibers is preferable. In this case, it is preferable to contain heat-fusible fibers as the synthetic fibers. That is, as the base material of the absorption sheet, a non-woven fabric containing heat-fusible fibers obtained by the airlaid method is preferable. The fineness of the heat-fusible fibers is preferably 0.5 dtex or more, more preferably 1.0 dtex or more, preferably 10.0 dtex or less, and more preferably 7.0 dtex or less. The fiber length of the heat-fusible fibers is preferably 1.1 mm or more, more preferably 2.0 mm or more, preferably 10.0 mm or less, and more preferably 6.0 mm or less.

[0021] The airlaid nonwoven fabric preferably has a water-absorbent fiber content in the constituent fibers of 15% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, particularly preferably 50% by mass or more, and preferably 80% by mass or less, more preferably 75% by mass or less, still more preferably 70% by mass or less.

[0022] For the constituent fibers other than the water-absorbent fibers, a film of an organic acid is formed on the surface of the fibers, and these organic acids elute into the drip relatively early. In contrast, the organic acids that have penetrated into the interior of the water-absorbent fibers elute into the drip relatively slowly. Therefore, if the content of the water-absorbent fibers in the constituent fibers is within the above range, when the exudation of the drip starts, first, the organic acids applied to the surface of the fibers other than the water-absorbent fibers elute into the drip, and then, the organic acids applied to the interior of the water-absorbent fibers gradually elute into the drip. Therefore, from the start of the exudation of the drip, the effect of preventing the drip from spoiling by the organic acid will continue for a long time.

[0023] The basis weight of the base material of the absorption sheet is preferably 20 g / m 2 or more, more preferably 30 g / m 2 or more, still more preferably 40 g / m 2 or more, and preferably 250 g / m 2 or less, more preferably 200 g / m 2 or less, still more preferably 180 g / m 2 or less.

[0024] The organic acid solution is obtained by dissolving an organic acid in a solvent, and the organic acid concentration is less than the saturation concentration. The solvent is not particularly limited as long as it can dissolve the organic acid. Examples of the solvent include water and hydrophilic organic solvents. Examples of the hydrophilic organic solvents include alcohols such as ethanol, isopropanol, and propylene glycol.

[0025] The organic acid solution has an organic acid concentration less than the saturation concentration. The saturation concentration is the saturation concentration at the temperature when the organic acid solution is brought into contact with the base material of the absorption sheet. That is, when the organic acid solution is brought into contact with the base material of the absorption sheet, it is considered that all of the organic acid contained in the organic acid solution is dissolved in the solvent.

[0026] Preferably, the concentration of the organic acid in the organic acid solution is 85% or less, more preferably 80% or less, and even more preferably 75% or less with respect to the saturation concentration. If the concentration of the organic acid in the solution is 85% or less with respect to the saturation concentration, the amount of the organic acid solution used increases, and the organic acid can be more uniformly applied in the thickness direction of the base material of the absorption sheet, and the dropout of the organic acid can be further suppressed.

[0027] The method of bringing the organic acid solution into contact with the base material of the absorption sheet is not particularly limited, and examples thereof include a method of spraying the organic acid solution onto the base material of the absorbent sheet, a method of immersing the base material of the absorbent sheet in the organic acid solution, and the like.

[0028] The method of removing the solvent from the base material of the absorption sheet is not particularly limited, and examples thereof include natural drying, heat drying, vacuum drying, and the like.

[0029] The organic acid-containing drip sheet may be composed only of the absorption sheet, but preferably has the absorption sheet and a liquid-permeable sheet laminated on the absorption sheet. By having the liquid-permeable sheet, if food is placed on the liquid-permeable sheet side, the drip absorbed by the absorption sheet is suppressed from flowing back (wet back) to the food.

[0030] As the liquid-permeable sheet, a resin film having a large number of through holes is preferable. Examples of the resin constituting the resin film include polyolefin resins, polyester resins, polyamide resins, and the like. The resin film may be blended with additives such as deodorants, antibacterial agents, colorants, and hydrophilic agents in the resin.

[0031] The thickness of the resin film is preferably 0.1 mm or more, more preferably 0.3 mm or more, preferably 1 mm or less, and more preferably 0.9 mm or less.

[0032] The basis weight of the resin film is preferably 20 g / m 2 or more, more preferably 22 g / m 2 or more, even more preferably 25 g / m 2 or more, and preferably 70 g / m 2 or less, more preferably 65 g / m 2 or less, even more preferably 60 g / m 2 or less.

[0033] The planar shape of the opening of the through-hole in the resin film is not particularly limited, and examples thereof include polygonal shapes such as triangles, quadrilaterals, pentagons, hexagons, heptagons, and octagons, and rounded polygons; circular shapes such as circles, ellipses, and oblongs. Further, the planar shape of the opening of the through-hole may be a combination of two or more. The dimension of the planar shape of the through-hole in the resin film is not particularly limited and may be adjusted as appropriate, but is preferably 0.1 mm to 1.5 mm.

[0034] It is preferable that the area of the opening of the through-hole on the placed surface of the object to be stored is larger than the area of the opening on the non-placed surface of the object to be stored. By configuring in this way, dripping absorbed by the absorption sheet is further suppressed from flowing back (wet back) to the food.

[0035] The inner wall of the through-hole is preferably formed in a tapered shape such that the inner diameter becomes narrower from the opening on the placed surface of the object to be stored toward the opening on the non-placed surface of the object to be stored. By making the inner wall tapered, dripping easily flows from the placed surface side of the object to be stored toward the non-placed surface side of the object to be stored.

[0036] Preferably, the through hole has a protruding portion that protrudes inward from the opening on the non-placement surface of the object to be stored. By having the protruding portion, the opening on the non-placement surface of the object to be stored is formed with a smaller diameter than the opening assumed on the extension line of the tapered inner wall due to this protruding portion. Thereby, it is possible to reliably prevent the backflow (wet back) of the drip from the absorption sheet.

[0037] When the organic acid-containing drip sheet has an absorption sheet and a liquid-permeable sheet laminated on the absorption sheet, after producing the absorption sheet by applying an organic acid to the base material of the absorption sheet, the absorption sheet and the liquid-permeable sheet may be integrated, or after integrating the base material of the absorption sheet and the liquid-permeable sheet, an organic acid may be applied to the base material of the absorption sheet.

[0038] As a method for integrating the absorption sheet and the liquid-permeable sheet, known hot melt methods, thermocompression embossing methods, and methods using a heat-adhesive resin powder can be applied. Among these, in order not to inhibit the performance of the absorption sheet, it is preferable to bond the absorption sheet and the liquid-permeable sheet by a hot melt method using a hot melt adhesive. Examples of the hot melt adhesive include polyolefin, polyvinyl acetate, and synthetic rubber. The coating amount of the hot melt adhesive is preferably 1 g / m 2 or more, more preferably 2 g / m 2 or more, and preferably 20 g / m 2 or less, more preferably 15 g / m 2 is preferable.

[0039] (Embodiment) Referring to FIGS. 1 to 3, an example of an embodiment of the organic acid-containing drip sheet of the present invention will be described. FIG. 1 is a perspective view of an example of the organic acid-containing drip sheet of the present invention. FIG. 2 is an enlarged plan view of the organic acid-containing drip sheet of FIG. 1. FIG. 3 is a schematic cross-sectional view taken along line V-V of FIG. 2. In the drawings, arrow x represents the width direction, arrow y represents the longitudinal direction, and arrow z represents the thickness direction. Also, the direction on the plane formed by arrows x and y is the plane direction. In FIGS. 1 to 3, the upper side in the thickness direction is the placement surface for the object to be preserved, and a liquid-permeable sheet is disposed on the side of the placement surface for the object to be preserved.

[0040] The organic acid-containing drip sheet 1 shown in FIG. 1 has an absorption sheet 2 and a liquid-permeable sheet 3 laminated on the plane of the absorption sheet 2 on the side where the object to be preserved (food) is placed.

[0041] The absorption sheet 2 has a base material that is an airlaid nonwoven fabric composed of water-absorbent fibers and synthetic fibers, and an organic acid is imparted to this base material. Also, the organic acid in the absorption sheet 2 is obtained by dissolving an organic acid in a solvent. After bringing an organic acid solution having an organic acid concentration less than the saturation concentration into contact with the base material of the absorption sheet 2, the solvent is removed to impart it.

[0042] The liquid-permeable sheet 3 is a resin film having a large number of through-holes. The surface of the liquid-permeable sheet 3 that is joined to the absorption sheet 2 is the non-placement surface for the object to be preserved, and the surface on the side opposite to the absorption sheet 2 is the placement surface side for the object to be preserved.

[0043] As shown in FIGS. 2 and 3, the liquid-permeable sheet 3 has a large number of through-holes 4. The opening area of the opening (large-diameter opening) 4a on the placement surface for the object to be preserved is formed to be larger than the opening area of the opening (small-diameter opening) 4b on the non-placement surface for the object to be preserved. Note that the planar shape of the large-diameter opening 4a and the planar shape of the small-diameter opening 4b are both rounded pentagons.

[0044] As shown in Fig. 3, the inner wall 4c of the through hole 4 is formed such that the inner diameter becomes narrower from the large-diameter opening 4a toward the small-diameter opening 4b. In Fig. 3, the inner wall 4c is formed to be convex and curved toward the large-diameter opening 4a side, but it may be formed in a tapered shape. Further, the through hole 4 has a protruding portion 4d that protrudes inward of the through hole 4 at the small-diameter opening 4b on the non-placement surface of the object to be stored.

[0045] The organic acid-containing drip sheet 1 shown in Fig. 1 has a rectangular shape in plan view, but the plan view shape is not particularly limited and may be appropriately changed according to the application. Further, the plan view shape of the through hole 4 formed in the liquid-permeable sheet is not limited to a rounded pentagon, and other shapes may be used.

[0046] Figs. 4 and 5 show other examples of the cross-sectional shape of the through hole 4. Fig. 4 is an enlarged plan view of another example of the organic acid-containing drip sheet of Fig. 1. Fig. 5 is a schematic cross-sectional view taken along line V-V of Fig. 4.

[0047] As shown in Figs. 4 and 5, also in other examples, the liquid-permeable sheet 3 has a large number of through holes 4. In this through hole 4, the opening area of the opening (large-diameter opening) 4e on the placement surface of the object to be stored is formed to be larger than the opening area of the opening (small-diameter opening) 4f on the non-placement surface of the object to be stored. Note that both the plan view shape of the large-diameter opening 4e and the plan view shape of the small-diameter opening 4f are substantially circular.

[0048] As shown in Fig. 5, the inner wall 4g of the through hole 4 is formed such that the inner diameter becomes narrower from the large-diameter opening 4e toward the small-diameter opening 4f. In the through hole 4 shown in Fig. 5, the inner wall 4g has a curved portion 4h and a straight portion 4i. In the curved portion 4h, the inner wall 4g is convex and curved toward the large-diameter opening 4e side. The straight portion 4i is formed in a tapered shape such that the inner diameter becomes narrower from the large-diameter opening 4e side toward the small-diameter opening 4f side. Note that the straight portion 4i may be formed such that the inner diameter is constant from the large-diameter opening 4e side toward the small-diameter opening 4f side.

Example

[0049] Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited by the following examples, and any modifications and embodiments within the scope not departing from the gist of the present invention are all included in the scope of the present invention.

[0050] [Preparation of the base material of the absorption sheet] An airlaid nonwoven fabric composed of water-absorbing fibers and synthetic fibers was produced as the base material of the absorption sheet. Specifically, a conjugate fiber (heat-sealable fiber) with a fineness of 1.7 dtex and a length of 3 mm having a core of polyethylene terephthalate (PET) and a sheath of polyethylene (PE) and cellulose fibers (wood ground pulp) were uniformly dispersed and deposited on a wire mesh. This deposit was heat-treated in an oven at 140 °C for 10 seconds to produce an airlaid nonwoven fabric (basis weight 125 g / m 2 ). The content of cellulose fibers in the airlaid nonwoven fabric was 60% by mass, and the content of heat-sealable fibers was 40% by mass.

[0051] [Preparation of the drip sheet] Drip sheet No.1 Sorbic acid was dissolved in ethanol at a liquid temperature of 25 °C to prepare a 3% by mass sorbic acid solution. The concentration of the sorbic acid solution is 75% or less with respect to the saturated concentration. The base material of the absorption sheet obtained above was sprayed with a sorbic acid solution (concentration 3% by mass) and dried to produce Absorption sheet No.1. The content of sorbic acid in Absorption sheet No.1 is 0.3 g / m 2 . The obtained Absorption sheet No.1 was used as Drip sheet No.1.

[0052] Drip sheet No.2 Fumaric acid was dissolved in ethanol at a liquid temperature of 25 °C to prepare a 3% by mass fumaric acid solution. The concentration of the fumaric acid solution is 75% or less with respect to the saturated concentration. The base material of the absorption sheet obtained above was sprayed with a fumaric acid solution (concentration 3% by mass) and dried to produce Absorption sheet No.2. The content of fumaric acid in Absorption sheet No.2 is 0.3 g / m 2It was so. The obtained absorption sheet No. 2 was designated as drip sheet No. 2.

[0053] Drip sheet No. 3 Adipic acid was dissolved in ethanol at a liquid temperature of 25°C to prepare an adipic acid solution with a concentration of 3% by mass. The concentration of the adipic acid solution is 75% or less with respect to the saturated concentration. The adipic acid solution (concentration 3% by mass) was sprayed onto the base material of the absorption sheet obtained above and dried to produce absorption sheet No. 3. The content of adipic acid in absorption sheet No. 3 is 0.3 g / m 2 It was so. The obtained absorption sheet No. 3 was designated as drip sheet No. 3.

[0054] Drip sheet No. 4 Succinic acid was dissolved in water at a liquid temperature of 25°C to prepare an aqueous succinic acid solution with a concentration of 3% by mass. The concentration of the aqueous succinic acid solution is 75% or less with respect to the saturated concentration. The aqueous succinic acid solution (concentration 3% by mass) was sprayed onto the base material of the absorption sheet obtained above and dried to produce absorption sheet No. 4. The content of succinic acid in absorption sheet No. 4 is 0.3 g / m 2 It was so. The obtained absorption sheet No. 4 was designated as drip sheet No. 4.

[0055] Drip sheet No. 5 Oxalic acid dihydrate was dissolved in water at a liquid temperature of 25°C to prepare an aqueous oxalic acid solution with a concentration of 3% by mass. The concentration of the aqueous oxalic acid solution is 75% or less with respect to the saturated concentration. The aqueous oxalic acid solution (concentration 3% by mass) was sprayed onto the base material of the absorption sheet obtained above and dried to produce absorption sheet No. 5. The content of oxalic acid in absorption sheet No. 5 is 0.3 g / m 2 It was so. The obtained absorption sheet No. 5 was designated as drip sheet No. 5.

[0056] Drip sheet No. 6 Citric acid was dissolved in water at a liquid temperature of 25°C to prepare an aqueous citric acid solution with a concentration of 3% by mass. The concentration of the aqueous citric acid solution is 75% or less with respect to the saturated concentration. An aqueous citric acid solution (concentration: 3% by mass) was sprayed onto the base material of the absorption sheet obtained above, and then dried to produce Absorption Sheet No. 6. The citric acid content of Absorption Sheet No. 6 was 0.3 g / m 2 . The obtained Absorption Sheet No. 6 was designated as Drip Sheet No. 6.

[0057] Drip Sheet No. 7 Linoleic acid was dispersed in ethanol at a liquid temperature of 25°C to prepare a linoleic acid dispersion with a concentration of 3% by mass. The linoleic acid dispersion was sprayed onto the base material of the absorption sheet obtained above, and then dried to produce Absorption Sheet No. 7. The linoleic acid content of Absorption Sheet No. 7 was 0.3 g / m 2 . The obtained Absorption Sheet No. 7 was designated as Drip Sheet No. 7.

[0058] Drip Sheet No. 8 Absorption Sheet No. 4 was produced in the same manner as the production method of Drip Sheet No. 4. A hot melt adhesive (polyolefin) was applied to one surface of this Absorption Sheet No. 4 in an amount of 2 g / m 2 . A resin film (thickness: 0.5 mm, basis weight: 22 g / m 2 , and the dimensions of the planar shape of the through holes were 0.1 mm to 1.5 mm) having a large number of through holes as a liquid-permeable sheet was laminated thereon. Subsequently, the absorption sheet and the liquid-permeable sheet were joined by the hot melt method to produce Drip Sheet No. 8. The resin film has through-holes as shown in FIGS. 2 and 3. The through-holes are formed such that the opening area of the large-diameter opening in the placed surface of the object to be stored (the plane on the side opposite to the absorption sheet) is larger than the opening area of the small-diameter opening in the non-placed surface of the object to be stored (the plane on the side joined to the absorption sheet). Note that the planar shape of the large-diameter opening and the planar shape of the small-diameter opening are both rounded pentagons. Further, the inner wall of the through-hole is formed in a tapered shape such that the inner diameter becomes narrower from the large-diameter opening toward the small-diameter opening, and the small-diameter opening has a protruding portion that protrudes inward of the through-hole. An enlarged photograph of the placed surface of the object to be stored of the resin film (FIG. 6(a)) and an enlarged photograph of the non-placed surface of the object to be stored (FIG. 6(b)) are shown in FIG. 6.

[0059] Drip sheet No. 9 In the same manner as the manufacturing method of drip sheet No. 6, absorption sheet No. 6 was produced. On one surface of this absorption sheet No. 6, a hot melt adhesive (polyolefin) was applied in an amount of 2 g / m 2 such that the amount became, and the same liquid-permeable sheet as drip sheet No. 8 was laminated thereon in the same manner as drip sheet No. 8. Next, the absorption sheet and the liquid-permeable sheet were joined by the hot melt method to produce drip sheet No. 9.

[0060] Drip sheet No. 10 Fumaric acid was dissolved in water at a liquid temperature of 25°C to prepare an aqueous fumaric acid solution with a concentration of 0.5 mass%. Note that the concentration of the aqueous fumaric acid solution is 80% or less with respect to the saturated concentration. The obtained base material of the absorption sheet was sprayed with an aqueous fumaric acid solution (concentration: 0.5 mass%) and dried to produce absorption sheet No. 10. The content of fumaric acid in absorption sheet No. 10 is 0.1 g / m 2 is. The obtained absorption sheet No. 10 was used as drip sheet No. 10.

[0061] Drip sheet No. 11 Fumaric acid was dissolved in water at a liquid temperature of 25°C to prepare an aqueous fumaric acid solution with a concentration of 0.5 mass%. Note that the concentration of the aqueous fumaric acid solution is 80% or less with respect to the saturated concentration. On the base material of the absorption sheet obtained above, an aqueous fumaric acid solution (concentration: 0.5% by mass) was sprayed and dried to produce Absorption Sheet No. 11. The content of fumaric acid in Absorption Sheet No. 11 was 0.033 g / m 2 It was thus obtained. The obtained Absorption Sheet No. 11 was designated as Drip Sheet No. 11.

[0062] Drip Sheet No. 12 Fumaric acid was dissolved in water at a liquid temperature of 25°C to prepare an aqueous fumaric acid solution with a concentration of 0.5% by mass. The concentration of the aqueous fumaric acid solution was 80% or less of the saturation concentration. On the base material of the absorption sheet obtained above, an aqueous fumaric acid solution (concentration: 0.5% by mass) was sprayed and dried to produce Absorption Sheet No. 12. The content of fumaric acid in Absorption Sheet No. 12 was 0.024 g / m 2 It was thus obtained. The obtained Absorption Sheet No. 12 was designated as Drip Sheet No. 12.

[0063] Drip Sheet No. 13 Fumaric acid was dispersed in water at a liquid temperature of 25°C to prepare a fumaric acid dispersion with a concentration of 3% by mass. The concentration of the fumaric acid dispersion exceeded the saturation concentration. On the base material of the absorption sheet obtained above, a fumaric acid dispersion (concentration: 3% by mass) was sprayed and dried to produce Absorption Sheet No. 13. The content of fumaric acid in Absorption Sheet No. 13 was 0.1 g / m 2 It was thus obtained. The obtained Absorption Sheet No. 13 was designated as Drip Sheet No. 13.

[0064] Drip Sheet No. 14 An organic acid was not imparted to the base material of the absorption sheet obtained above, and it was directly designated as Drip Sheet No. 14.

[0065] [Confirmation of the loading mode of the organic acid] For Drip Sheets No. 10 and No. 13, in order to confirm the loading property of the organic acid on the absorption sheet, an organic acid desorption test was conducted. Also, in order to confirm the mode of imparting the organic acid to the absorption sheet, Drip Sheets No. 10 and No. 13 were observed by a scanning electron microscope (SEM).

[0066] (Organic acid desorption test) The drip sheet was cut into pieces with a length of 12 cm and a width of 7 cm to prepare test pieces. The test pieces were placed in the sieve frame of a vibrating sieve machine (manufactured by Labonekt, small vibrating sieve machine "KS-300") equipped with a sieve net with an aperture of 2.00 mm (10 mesh). After vibrating the vibrating sieve machine for 10 minutes, the presence or absence of organic acid desorbed from the upper and lower surfaces of the test pieces was confirmed and evaluated according to the following criteria. For drip sheet No. 10, no desorbed organic acid was confirmed on the surface of the test piece or at the discharge port of the vibrating sieve machine. For drip sheet No. 13, organic acid particles were confirmed on the surface of the test piece or at the discharge port of the vibrating sieve machine.

[0067] (SEM observation) The SEM photographs of drip sheet No. 10 (absorbent sheet No. 10) are shown in Fig. 7. The SEM photographs of drip sheet No. 10 (absorbent sheet No. 10) after the organic acid desorption test are shown in Fig. 8. The SEM photographs of drip sheet No. 13 (absorbent sheet No. 13) are shown in Fig. 9. As shown in Fig. 7, for drip sheet No. 10, an organic acid film was formed on the surface of the fibers constituting the base material of the absorbent sheet, and no organic acid particles were present. And as shown in Fig. 8, for drip sheet No. 10, even after the organic acid desorption test, an organic acid film was formed on the surface of the fibers constituting the base material of the absorbent sheet, and the organic acid did not desorb. In contrast, as shown in Fig. 9, for drip sheet No. 13, organic acid particles are present on the surface of the fibers constituting the base material of the absorbent sheet. Therefore, it is considered that these organic acids desorbed in the organic acid desorption test.

[0068] [Evaluation of drip sheet] Using the drip sheets No. 1 to 14 prepared above, the preservation of food (meat) was carried out, and the degree of food discoloration and the presence or absence of bad odor generation were evaluated.

[0069] (Evaluation method) As the food to be stored, Australian beef thigh meat (lean part) was used. The beef thigh meat block was cut into pieces about 1 cm thick, 5 cm long, and 3 cm wide, and left for 1 hour. Then, the cut meat was placed on a food packaging wrap sheet (manufactured by Asahi Kasei Home Products Corporation, Saran Wrap (registered trademark) (polyvinylidene chloride)), and through this wrap sheet, the R value (R1) of the lower surface of the cut meat was measured using a color difference meter (Color Analyzer RGB - 1002, manufactured by Sato Shoji Co., Ltd.). Next, 1 mL of water in which two adults washed their hands (rubbed and washed 20 times with both hands) in 2 L of pure water was sprayed onto the upper surface of the cut meat. The lower surface and all sides of the cut meat were covered with a drip sheet and stored for 5 hours in an environment of 28 ± 2°C and a relative humidity of 70 ± 5%. An odor sensory test was conducted on the cut meat and the drip sheet after storage. For the evaluation of the odor sensory test, those without a putrid odor were marked as "〇", and those with even a slight putrid odor confirmed were marked as "×". Also, the drip sheet was peeled off from the cut meat after storage, and the cut meat was placed on the food packaging wrap sheet. Through this wrap sheet, the R value (R2) of the lower surface of the cut meat after storage was measured using the color difference meter. The measurement with the color difference meter was performed at five different locations on the lower surface of the cut meat, and the average value was obtained. For the evaluation of the degree of color change, when the change rate of the R value (= (R2 - R1) / R1 × 100) was less than 25%, it was marked as "◎", when it was 25% or more and less than 30%, it was marked as "〇", when it was 30% or more and less than 45%, it was marked as "×", and when it was 45% or more, it was marked as "××".

[0070] The measurement results of the odor sensory test and the color difference meter are shown in Tables 1 and 2.

[0071]

Table 1

[0072]

Table 2

[0073] Drip sheets No. 1 to 4, 8, 10, and 11 have an absorption sheet containing an organic acid, the solubility of the organic acid in water at 30 °C is 0.3 g / 100 mL to 12 g / 100 mL, and the content of the organic acid in the absorption sheet is 0.03 g / m 2 or more, and the organic acid in the absorption sheet is imparted by contacting an organic acid solution with a concentration less than the saturation concentration with the base material of the absorption sheet and then removing the solvent. These drip sheets No. 1 to 4, 8, 10, and 11 suppressed the generation of bad odors due to drip spoilage and were able to suppress the discoloration of foods.

[0074] Drip sheets No. 5, 6, and 9 are cases where the solubility of the organic acid contained in the absorption sheet in water at 30 °C exceeds 12 g / 100 mL. Although the generation of bad odors due to drip spoilage was suppressed in these drip sheets No. 5, 6, and 9, since the amount of the organic acid dissolved in the drip was too large, the food was discolored by the organic acid, and it is considered that the degree of food discoloration increased.

[0075] Drip sheet No. 7 is a case where the solubility of the organic acid contained in the absorption sheet in water at 30 °C is less than 0.3 g / 100 mL. Since the organic acid did not dissolve out into the drip in this drip sheet No. 7, the drip spoiled and a bad odor occurred.

[0076] Drip sheet No. 12 is a case where the content of the organic acid in the absorption sheet is less than 0.03 g / m 2 or less. Since the content of the organic acid is too small in this drip sheet No. 12, it is considered that the drip spoiled and a bad odor occurred.

[0077] Drip sheet No. 13 is a case where the organic acid in the absorption sheet is imparted by contacting an organic acid dispersion with a concentration exceeding the saturation concentration with the base material of the absorption sheet and then removing the solvent. This drip sheet No. 13 had a small surface area because fumaric acid existed in large particles, and dissolution into the drip was insufficient within a predetermined time, resulting in the drip spoiling and generating a bad odor.

[0078] Drip sheet No. 14 is a case where the absorbent sheet does not contain an organic acid. Since there is no organic acid in this drip sheet No. 14, spoilage of the drip could not be suppressed, and a bad odor was generated.

Explanation of reference signs

[0079] 1: Organic acid-containing drip sheet, 2: Absorbent sheet, 3: Liquid-permeable sheet, 4: Through-hole

Claims

Claim 1 A drip sheet used for storing food, wherein the drip sheet includes at least one layer of absorbent sheet, the absorbent sheet contains an organic acid, the organic acid has a solubility in water at 30°C of 0.3 g / 100 mL to 12 g / 100 mL, The content of the organic acid in the absorption sheet is 0.03 g / m 2 or more, the organic acid in the absorbent sheet is obtained by contacting a solution of the organic acid dissolved in a solvent, with a base material of the absorbent sheet, and then removing the solvent, the organic acid concentration being less than the saturation concentration, and is characterized by an organic acid-containing drip sheet. Claim 2 The content of the organic acid in the absorption sheet is 0.5 g / m 2 The organic acid-containing drip sheet according to claim 1, wherein the content is 0.5 g / m or less. Claim 3 The organic acid-containing drip sheet according to claim 1, wherein the concentration of the organic acid in the solution is 85% or less of the saturation concentration. Claim 4 The base material of the absorbent sheet is a nonwoven fabric containing heat-sealable fibers obtained by an airlaid method, the heat-sealable fibers having a fineness of 0.5 dtex to 10.0 dtex and a fiber length of 1.1 mm to 10.0 mm, and the organic acid-containing drip sheet according to any one of claims 1 to 3. Claim 5 the drip sheet has an absorbent sheet and a liquid-permeable sheet laminated on the absorbent sheet, the liquid-permeable sheet is a resin film having a large number of through holes, the through holes are formed such that the opening area on the placed surface of the object to be stored is larger than the opening on the non-placed surface of the object to be stored, and the organic acid-containing drip sheet according to any one of claims 1 to 3.

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