JP5848477B1 - Fibrous casing and manufacturing method thereof - Google Patents

Abstract

An object of the present invention is to provide a fibrous casing excellent in liquid retention and release properties of food modifiers and the like. A fibrous casing according to the present invention is a fibrous casing used as a food packaging material in the heat treatment of food, and is formed from a paper material that is disposed as an innermost layer and has pulp as a main component. A paper layer and a synthetic resin layer laminated on the outer surface of the paper layer are provided, and the inner surface of the paper material is a non-glossy surface, and the outer surface is a glossy surface. The synthetic resin layer preferably includes an oxygen barrier resin layer having an oxygen barrier property and a water vapor barrier resin layer having a water vapor barrier property. The innermost layer of the synthetic resin layer is the water vapor barrier resin layer, and the lamination of the synthetic resin layer on the outer surface of the paper layer is a polyethylene layer that forms the water vapor barrier resin layer as the innermost layer of the synthetic resin layer. It is preferably performed by extrusion lamination. [Selection] Figure 1

Description

  The present invention relates to a fibrous casing.

  Conventionally, a fiber casing for packaging processed meat products such as ham and sausage is known. As such a fibrous casing, one having an inner layer mainly composed of pulp and an outer layer laminated on the outer surface side of the inner layer is known. Fibrous casings with such inner and outer layers contain food modifiers such as smoke, seasonings, pigments and preservatives in the inner layer, and transfer these components to the contents during cooking. Can do.

  As a fibrous casing having such an inner layer and an outer layer, a packaging material formed by laminating, for example, paper (inner layer) and a heat-sealable nonwoven fabric (outer layer) has been proposed (see JP-A-6-31494). This packaging material is formed by laminating paper and non-woven fabric and adhering them together by impregnating the viscose liquid into the interface between them. In such a packaging material, the paper and the nonwoven fabric can be bonded together with the viscose liquid, and the paper is coated with the viscose liquid to improve the peelability between the paper and the contents.

  However, since such a conventional brass casing uses the viscose liquid as described above, the cost increases and the manufacturing process becomes complicated. Further, the fibrous casing can hold a sufficient amount of food modifier in the inner layer, and has a function of efficiently transferring (releasing) the food modifier to the packaged food. Required. However, when general paper is used for the inner layer, the liquid retention and release properties are not sufficient.

JP-A-6-31494

  This invention is made | formed based on such a situation, and the objective of this invention is providing the fiber casing which is excellent in liquid retention property and discharge | release properties, such as a food modifier.

  The fibrous casing according to the present invention made to solve the above problems is a fibrous casing used as a food packaging material in the heat treatment of food, and is disposed as an innermost layer, and has pulp as a main component. A paper layer formed from a paper material and a synthetic resin layer laminated on the outer surface of the paper layer, wherein the inner surface of the paper material is a non-glossy surface and the outer surface is a glossy surface.

  In the fibrous casing, the inner surface (the surface in contact with the food) of the paper material forming the paper layer in contact with the packaged food is a non-glossy surface. Therefore, according to the fiber casing, since the surface area of the inner surface of the paper layer in contact with the food is large, the release property (transferability to food) of the food modifier impregnated in the paper layer is high. Further, the outer surface of the paper material (paper layer) is a glossy surface, and the pulp fibers are bonded to each other on the glossy surface, and there are few voids. For this reason, the impregnated food modifier cannot be impregnated to the vicinity of the outer surface in the paper layer, and the release property of the food modifier to the inner surface side is further increased. Furthermore, since the outer surface of the paper material is a glossy surface, for example, when the paper layer and the synthetic resin layer are laminated by extrusion lamination, the resin that forms the synthetic resin layer is difficult to impregnate the paper layer. Therefore, according to the fibrous casing, the thickness of the paper layer having a sufficient gap can be ensured even in the laminated state with the synthetic resin layer, and the liquid retaining property can be improved.

  The synthetic resin layer preferably includes an oxygen barrier resin layer having an oxygen barrier property and a water vapor barrier resin layer having a water vapor barrier property. As described above, when the synthetic resin layer includes the oxygen barrier resin layer and the water vapor barrier resin layer, the food can be cooked and the food modifier can be effectively transferred to the food. . Nylon is preferable as the resin for forming the oxygen barrier resin layer. Polyethylene is preferable as the resin for forming the water vapor barrier resin layer.

  The innermost layer of the synthetic resin layer may be the water vapor barrier resin layer. In this case, the synthetic resin layer is preferably laminated on the outer surface of the paper layer by extrusion lamination of polyethylene forming a water vapor barrier resin layer as the innermost layer of the synthetic resin layer. Thus, the adhesiveness of a paper layer and a synthetic resin layer can be improved by laminating | stacking a synthetic resin layer on a paper layer by the extrusion lamination using polyethylene which is a thermoplastic resin.

  The paper layer preferably contains a food modifier impregnated in the paper material, and the food modifier preferably contains a pigment, a fragrance, or a combination thereof. By impregnating the paper material with such a food modifier, it is possible to impart color and flavor to the food during the heat treatment.

The “Fibrous casing” is a heat treatment such as smoke treatment in the state that food such as processed meat products is packaged. It means a casing capable of transferring a food modifier such as an agent to food. The main component is the most abundant component among the components. “Glossy surface” refers to a surface having gloss and an arithmetic average roughness Ra of 3 μm or less. “Non-glossy surface” refers to a surface having no gloss and an arithmetic average roughness Ra of 3 μm or more. “Having oxygen barrier properties” means that the oxygen permeability at 20 ° C. and 90% RH is 100 cc / m ² · 24 hr · atm or less. “Having water vapor barrier properties” means that the water vapor permeability at 40 ° C. and 90% RH is 50 g / m ² · 24 hr or less.

  As described above, the fibrous casing of the present invention is excellent in liquid retention and release properties such as food modifiers.

It is sectional drawing of the fiber casing which concerns on one Embodiment of this invention.

<Fibrous casing>
1 includes a paper layer 2 disposed as an innermost layer, and a synthetic resin layer 3 laminated on the outer surface of the paper layer 2. The fiber casing 1 is used as a packaging material for the food during the heat treatment of the food.

  The paper layer 2 is formed from a paper material whose main component is pulp (preferably natural pulp). The content of pulp (preferably natural pulp) in the paper material is usually 50% by mass or more, preferably 90% by mass or more, and more preferably 95% by mass or more. The inner surface 2a of the paper material (paper layer 2) is a non-glossy surface, and the outer surface 2b is a glossy surface.

  In the fiber casing 1, the inner surface 2a (the surface in contact with the food) of the paper material forming the paper layer 2 is a non-glossy surface, and the surface area of the inner surface of the paper layer 2 in contact with the food is large. Therefore, the release property (transferability) of the food modifier impregnated in the paper layer 2 to the food is enhanced. Further, the outer surface 2b of the paper material (paper layer 2) is a glossy surface, which further enhances the release to the inner surface side. Further, since the outer surface 2b of the paper layer 2 (paper material) is a glossy surface, even when the synthetic resin layer is laminated on the outer surface 2b side by extrusion lamination or the like, the resin that forms the synthetic resin layer 3 is the paper layer 2. Hard to impregnate inside. That is, according to the fibrous casing 1, the gap of the paper layer 2 is sufficiently secured, and high liquid retention can be exhibited.

  The paper material is usually obtained by papermaking a pulp slurry containing natural pulp.

  The natural pulp is not particularly limited, and examples thereof include waste paper pulp, chemical pulp, mechanical pulp, pulp obtained from sisal hemp, manila hemp, sugar cane, cotton, silk, bamboo, and kenaf. Among these, the natural pulp is preferably softwood bleached kraft pulp (NBKP). By using softwood bleached kraft pulp (NBKP) as the natural pulp, the fiber casing paper material has increased strength, a large fiber diameter, and a long fiber. The material can be sufficiently impregnated.

  Moreover, as said natural pulp, it is also preferable to use together the softwood bleached kraft pulp (NBKP) and the mercerized pulp which carried out the mercerization process of the softwood bleached kraft pulp (NBKP). By using the mercerized pulp in combination with softwood bleached kraft pulp (NBKP), it is possible to promote the reduction of the density of the paper material, and it is possible to more suitably impregnate the food modifier and the like. Moreover, as a minimum of the mass-based content ratio of the said softwood bleached kraft pulp (NBKP) and the said mercerized pulp, 4: 1 is preferable and 14: 3 is more preferable. On the other hand, the upper limit of the mass-based content ratio between the softwood bleached kraft pulp (NBKP) and the mercerized pulp is preferably 9: 1 and more preferably 18: 3. Due to the mass-based content ratio of the softwood bleached kraft pulp (NBKP) and the mercerized pulp being within the above range, the liquid absorbency, liquid retention and release properties of food modifiers and the like are enhanced while increasing the strength. (Separability) can be preferably improved.

  As a minimum of content of the above-mentioned natural pulp to all fiber constituents which form the above-mentioned paper material, it is 50 mass%, for example, 70 mass% is preferred, 90 mass% is more preferred, 95 mass% is still more preferred, 97 mass % Is more preferable, and 100% by mass is particularly preferable. When the content of the natural pulp component relative to the total fiber component is in the above range, the paper material can suppress uneven transfer of the food modifier and the like.

  The lower limit of the natural pulp freeness is preferably 350 ml, more preferably 400 ml, and even more preferably 430 ml. On the other hand, the upper limit of the freeness of the natural pulp is preferably 550 ml, more preferably 500 ml, and even more preferably 460 ml. When the freeness of the natural pulp is less than the lower limit, the density becomes too high, and the liquid absorbency, the liquid separating property, and the like may be lowered. On the other hand, when the freeness of the natural pulp exceeds the above upper limit, the air permeability may be lowered and the heat retaining property and the heat insulating property may be lowered. “Freeness” is a value based on JIS-P-8121 (2012).

  Examples of fiber components other than natural pulp in the fiber component constituting the paper material include rayon fiber, polyolefin fiber, polyester fiber, and other synthetic resin fibers. These can be used alone or in combination of two or more.

  The paper material preferably contains a paper strength enhancer as an additive. Examples of the paper strength enhancer include a wet paper strength enhancer and a dry paper strength enhancer.

  Examples of the wet paper strength enhancer include polyamide / epichlorohydrin resin, urea resin, acid colloid / melamine resin, thermal crosslinkability imparting PAM, and the like. The lower limit of the content (in terms of solid content) of the wet paper strength enhancer relative to 100 parts by mass of all pulp components or all fiber components is preferably 0.5 parts by mass, more preferably 1.5 parts by mass, and 2 parts by mass. Is more preferable. On the other hand, the upper limit of the content (in terms of solid content) of the wet paper strength enhancer with respect to 100 parts by mass of all pulp components or all fiber components is preferably 6 parts by mass, more preferably 5.5 parts by mass. Is more preferable. When content of the said wet paper strength agent is less than the said minimum, there exists a possibility that peelability with the content may not fully be improved. On the other hand, when the content of the wet paper strength agent exceeds the upper limit, the liquid absorbability may be reduced.

  Examples of the dry paper strength enhancer include cationic starch, amphoteric starch, polyacrylamide (PAM), and carboxymethylcellulose (CMC). The lower limit of the content (in terms of solid content) of the dry paper strength enhancer with respect to 100 parts by mass of all pulp components or all fiber components is preferably 0.2 parts by mass, more preferably 0.5 parts by mass. Is more preferable. On the other hand, the upper limit of the content (in terms of solid content) of the dry paper strength enhancer relative to 100 parts by mass of all pulp components or all fiber components is preferably 5.5 parts by mass, more preferably 5 parts by mass, Part by mass is more preferable. When the content of the dry paper strength enhancer is less than the lower limit, the peelability from the contents (food) may not be sufficiently improved. Conversely, if the content of the dry paper strength enhancer exceeds the upper limit, the liquid absorbability may be reduced.

  The paper material preferably contains a sizing agent as an additive. The said paper raw material can improve heat retention, heat insulation, etc. by containing a sizing agent. Examples of the sizing agent include rosin sizing agent, alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), various emulsion sizing agents, starch and the like. Among these, a rosin sizing agent that has a large effect of imparting water resistance and can improve the smoothness of the glossy surface when one surface of the paper material is formed as a glossy surface is preferable.

  Examples of the rosin sizing agent include modified rosin, reinforced rosin, saponified rosin, and emulsified rosin. Among these, a saponified rosin having a sufficient size effect and good dilution into a pulp slurry is more preferable.

  As a minimum of content (solid content conversion) of the above-mentioned size agent to 100 mass parts of all pulp ingredients or all fiber ingredients, 1 mass part is preferred, 1.5 mass parts is more preferred, and 1.7 mass parts is still more preferred. . On the other hand, the upper limit of the content of the sizing agent (solid content conversion) with respect to 100 parts by mass of all pulp components or all fiber components is preferably 3 parts by mass, more preferably 2.5 parts by mass, and 2.3 parts by mass. Further preferred. When content of the said sizing agent is less than the said minimum, there exists a possibility that heat retention and heat insulation may not fully be improved. On the other hand, when the content of the sizing agent exceeds the upper limit, the surface property of the paper material is lowered and the operability may be lowered.

  The said paper raw material may contain another additive in the range which does not impair the objective of this invention. Examples of such other additives include paper strength agents other than those described above; talc, calcium carbonate, kaolin, titanium dioxide, hydrated silicon, hydrated silicic acid (white carbon), urea-formalin polymer fine particles, regenerated particles, Examples thereof include fillers such as silica composite regenerated particles; coagulants such as sulfate bands and polyethyleneimines; flocculants such as polyacrylamide and copolymers thereof; charge control agents; antifoaming agents;

  The paper material is formed as a single glossy paper with one side being a glossy surface and the other side being a non-glossy surface.

The lower limit of the water absorption of the gloss surface at the contact time 20 seconds by the Bristow method, is preferably 20 ml / ^{m 2,} more preferably ^{22ml / m 2, 25ml / m} 2 is more preferred. In contrast, the upper limit of the water absorption of the gloss surface at the contact time 20 seconds by the Bristow method, is preferably 40 ml / ^{m 2,} more preferably ^{38ml / m 2, 35ml / m} 2 is more preferred. The lower limit of the water absorption of the non-gloss surface at the contact time 20 seconds by the Bristow method, is preferably 10 ml / ^{m 2,} more preferably ^{12ml / m 2, 15ml / m} 2 is more preferred. In contrast, the upper limit of the water absorption of the non-gloss surface at the contact time 20 seconds by the Bristow method, is preferably 35 ml / ^{m 2,} more preferably ^{33ml / m 2, 30ml / m} 2 is more preferred. Furthermore, it is preferable that the water absorption amount of the glossy surface in the contact time of 20 seconds by the Bristow method is larger than the water absorption amount of the non-glossy surface. The paper material is sufficiently impregnated with a food modifier or the like when the water absorption amount of the glossy surface and the non-glossy surface in the contact time of 20 seconds by the Bristow method is in the above range. While being able to transfer suitably, peelability from a foodstuff is further improved.

  The lower limit of the arithmetic average roughness Ra of the non-glossy surface that is the inner surface 2a is 3 μm, preferably 3.5 μm, and more preferably 4 μm. On the other hand, the upper limit of the arithmetic average roughness Ra of the non-glossy surface is preferably 10 μm, more preferably 8 μm, further preferably 6.5 μm, and particularly preferably 5 μm. By setting the arithmetic average roughness Ra of the non-glossy surface, which is the inner surface 2a, within the above range, the release properties of food modifiers and the like can be suitably increased. When the arithmetic average roughness Ra of the non-glossy surface that is the inner surface 2a is a smooth surface that is less than the above lower limit, the surface area is reduced and the release of food modifiers and the like is reduced. On the contrary, when the arithmetic average roughness Ra of the non-glossy surface which is the inner surface 2a exceeds the upper limit, the paper material is likely to stick to the food, and the peelability to the food decreases.

  The lower limit of the arithmetic average roughness Ra of the glossy surface that is the outer surface 2b can be 0.1 μm, preferably 0.5 μm, more preferably 1 μm, and even more preferably 1.5 μm. On the other hand, the upper limit of the arithmetic average roughness Ra of the glossy surface is 3 μm, preferably 2.5 μm, and more preferably 2 μm. By setting the arithmetic average roughness Ra of the glossy surface, which is the outer surface 2b, in the above range, it is possible to improve the release property of the food modifier and the like, the liquid retention property, and the like on the inner surface side. When the arithmetic average roughness Ra of the glossy surface that is the outer surface 2b is a rough surface that exceeds the above upper limit, the release property of the food modifier or the like impregnated from the inner surface 2a side to the inner surface 2a side decreases. In addition, when the arithmetic average roughness Ra of the glossy surface which is the outer surface 2b is a rough surface exceeding the above upper limit, the amount of impregnation from the outer surface 2b side of the resin forming the synthetic resin layer 3 is increased, and the liquid retaining property (retaining) Possible liquid volume) is reduced.

  The lower limit of the absolute value of the fiber orientation angle on the glossy surface is preferably 0 °. On the other hand, the upper limit of the absolute value of the fiber orientation angle of the glossy surface is preferably 3 °, more preferably 2.5 °, and even more preferably 2 °. Further, the lower limit of the absolute value of the fiber orientation angle of the non-glossy surface is preferably 0.5 °, more preferably 1 °, and further preferably 1.5 °. On the other hand, the upper limit of the absolute value of the fiber orientation angle of the non-glossy surface is preferably 4 °. Furthermore, it is preferable that the absolute value of the fiber orientation angle of the glossy surface is smaller than the absolute value of the fiber orientation angle of the non-glossy surface. In the paper material, the fiber orientation angle of the glossy surface (outer surface 2b) and the fiber orientation angle of the non-glossy surface (inner surface 2a) are in the above range, so that the fiber orientation on the glossy surface is dense and uniform. In addition, it is possible to enhance the liquid retaining property and the release property of the food modifier and the like from the non-glossy surface.

  The paper material preferably does not contain viscose. Since the content of natural pulp with respect to all pulp components is in the above range as described above, the paper material is prevented from adhering to the content even if it does not contain viscose. Peelability is improved. Furthermore, the paper material does not contain viscose, so that costs can be reduced and the manufacturing process can be facilitated.

The lower limit of the basis weight of the paper stock, preferably 14 g / ^{m 2,} more preferably ^{15g / m 2, 16g / m} 2 is more preferred. In contrast, the upper limit of the basis weight of the paper stock, preferably 30 g / ^{m 2,} more preferably ^{28g / m 2, 25g / m} 2 is more preferred. If the basis weight is less than the lower limit, the strength of the paper material may be reduced and may be easily broken. On the other hand, when the basis weight exceeds the upper limit, the rigidity of the paper material is increased, which may make it difficult to deform along the shape of the contents. In addition, "basis weight" is a value based on JIS-P-8124 (2011).

The lower limit of the density of the paper stock, preferably ^{0.25g / cm 3, 0.3g / cm} 3 is more preferable. On the other hand, the upper limit of the density of the paper material, preferably ^{0.6g / cm 3, 0.55g / cm} 3 is more preferable. When the density is less than the lower limit, the strength of the paper material is lowered and easily broken, and the heat retaining property and the heat insulating property may be lowered. On the other hand, when the density exceeds the upper limit, the rigidity of the paper material is increased, which may make it difficult to deform along the shape of the contents. The “density” is a value based on JIS-P-8118 (2012).

  The lower limit of the wet tensile strength in the machine direction of the paper material is preferably 0.20 kN / m, more preferably 0.25 kN / m, and still more preferably 0.30 kN / m. When the said longitudinal tensile strength is less than the said minimum, there exists a possibility that peelability with the content may not fully be improved.

  The lower limit of the paper thickness of the paper material is preferably 30 μm, more preferably 35 μm, and even more preferably 38 μm. On the other hand, the upper limit of the paper thickness of the paper material is preferably 75 μm, more preferably 70 μm, and even more preferably 68 μm. When the paper thickness is less than the lower limit, the liquid absorbability and liquid retention may be reduced. On the other hand, when the paper thickness exceeds the upper limit, the liquid separation property may be reduced.

  The method for producing a paper material includes a step of making a pulp slurry and a step of drying one side of the paper-made pulp with a Yankee dryer. In the paper material obtained by the method for producing the paper material, the contact surface with the Yankee dryer is formed as a glossy surface, and the non-contact surface with the Yankee dryer is formed as a non-glossy surface. According to the said manufacturing method, the said paper raw material can be manufactured suitably.

  Specifically, as a method for producing the paper material, a slurry in which various additives are added to a pulp slurry as necessary is obtained using a normal paper machine equipped with a wire part, a press part, a Yankee dryer, a calendar part, and the like. Examples include paper making methods. In addition, as the paper machine, for example, a normal wet paper machine such as a long net paper machine, an on-top paper machine, a twin-wire paper machine, a circular net paper machine, a short net paper machine, etc. can be used. it can. Among these, a circular net paper machine that can easily adjust the fiber orientation angle and increase the paper strength in the vertical direction is preferable. When a circular paper machine is used, the non-glossy surface becomes a dewatering surface with a wire, and the fine fibers are forcibly dehydrated, so that the non-glossy surface can be released more efficiently.

  The paper layer 2 contains a food modifier impregnated in the paper material. The food modifier imparts color, fragrance, flavor, and the like to food. As said food modifier, a pigment | dye, a fragrance | flavor, a preservative, a seasoning etc. can be mentioned. These can be used alone or in combination of two or more. Examples of the pigment include caramel and gardenia. Examples of the fragrance include kun liquid.

  The synthetic resin layer 3 includes an oxygen barrier resin layer 4, a first water vapor barrier resin layer 5 laminated on the inner surface of the oxygen barrier resin layer 4, and a second laminated on the outer surface of the oxygen barrier resin layer 4. This is a three-layer structure having the water vapor barrier resin layer 6. When the synthetic resin layer 3 has the oxygen barrier resin layer 4, it is possible to effectively cook food and transfer the food modifier to the food at this time. Moreover, since the synthetic resin layer 3 has the first water vapor barrier resin layer 5 and the second water vapor barrier resin layer 6, the food is cooked and the food modifier is transferred to the food at this time. Can be carried out effectively. Moreover, the preservability of foodstuffs etc. increase by providing these layers.

  Examples of the resin that forms the oxygen barrier resin layer 4 include heat such as polyolefin such as polyethylene and polypropylene, vinyl chloride resin, vinylidene chloride resin, polystyrene, polyester, polyamide, nylon (6-nylon, 6,6-nylon, etc.). A plastic resin can be mentioned. Among these, nylon is preferable from the viewpoints of exhibiting good oxygen barrier properties and good heat shrinkability. Although it does not restrict | limit especially as melting | fusing point of nylon, 215 degreeC or more and 225 degrees C or less can be used suitably.

20 ° C. oxygen barrier resin layer 4, the upper limit of the oxygen permeability at 90% ^RH, preferably 100cc / m 2 · 24hr · atm , 50cc / m 2 · 24hr · atm is more preferred. On the other hand, the lower limit can be to the numerical value approximates the ^0cc / m 2 · 24hr · atm as possible may, for example, ^{1.0cc / m 2 · 24hr · atm} . When the oxygen permeability of the oxygen barrier resin layer 4 is within the above range, good food storage stability and the like can be exhibited.

  As the oxygen barrier resin layer 4, a heat-shrinkable film (shrink film) formed by stretching a film formed from the above resin is usually used. The heat shrink temperature of the oxygen barrier resin layer 4 (shrink film) is not particularly limited, but is, for example, 70 ° C. or higher and 90 ° C. or lower. When the heat shrink temperature is in the above range, good shrinkage can be caused when cooking.

  Although it does not specifically limit as average thickness of the oxygen barrier resin layer 4, For example, 15 micrometers or more and 50 micrometers or less are preferable. By setting it as such an average thickness, coexistence with oxygen barrier property etc. and workability etc. can be aimed at.

  Examples of the resin that forms the first water vapor barrier resin layer 5 and the second water vapor barrier resin layer 6 include polyolefins such as polyethylene and polypropylene, and thermoplastic resins such as polyester. Among these, polyolefin is preferable and polyethylene is more preferable in terms of being able to exhibit good water vapor barrier properties and processability. Examples of polyethylene include high density polyethylene (HDPE), low density polyethylene (LDPE), and linear low density polyethylene (LLDPE). Although it does not restrict | limit especially as melting | fusing point of polyethylene, The thing of 105 to 115 degreeC can be used conveniently. The resin forming the first water vapor barrier resin layer 5 and the resin forming the second water vapor barrier resin layer 6 may be of the same type or different types.

  The average thickness of the first water vapor barrier resin layer 5 and the second water vapor barrier resin layer 6 is not particularly limited, but is preferably 15 μm or more and 50 μm or less, for example. By setting it as such an average thickness, coexistence with water vapor | steam barrier property etc. and workability etc. can be aimed at.

  The method for forming the first water vapor barrier resin layer 5 and the second water vapor barrier resin layer 6 is not particularly limited. For example, it may be formed by coating on the oxygen barrier resin layer 4, or the water vapor barrier resin layers 5 and 6 are bonded to the oxygen barrier resin layer 4 as a film made of a single layer of water vapor barrier resin. Also good. Further, as will be described later, the first water vapor barrier resin layer 5 in contact with the paper layer 2 may be formed at the time of extrusion lamination.

  Although it does not specifically limit as average thickness of the synthetic resin layer 3, For example, they are 30 micrometers or more and 300 micrometers or less.

  In the fibrous casing 1, the first water vapor barrier layer 5 which is the innermost layer of the synthetic resin layer 3 may be impregnated into the paper layer 2 from the outer surface side. In such a case, the lower limit of the average thickness of the impregnated portion of the first water vapor barrier layer 5 (the innermost layer of the synthetic resin layer 3) with respect to the average thickness of the paper layer 2 is preferably 1%, preferably 5% More preferred is 10%. On the other hand, as this upper limit, 70% is preferable, 50% is more preferable, 30% is further preferable, 20% is further preferable, and 10% is particularly preferable. When the ratio of the impregnated portion is less than the lower limit, the adhesive strength between the paper layer 2 and the synthetic resin layer 3 may not be sufficiently obtained. On the contrary, when the ratio of the impregnated part exceeds the upper limit, the food modifier or the like cannot be sufficiently impregnated into the paper layer 2, that is, the liquid retaining property may be lowered.

<Manufacturing method of fibrous casing>
Although it does not specifically limit as a manufacturing method of the said brass casing 1, It can manufacture efficiently by lamination processes, such as dry lamination and extrusion lamination. When manufacturing by dry lamination, it can carry out by laminating | stacking the paper raw material used as the paper layer 2, and the film of the three-layer structure used as the synthetic resin layer 3 on it. In the case of manufacturing by extrusion lamination, a paper material to be the paper layer 2 and a film having a two-layer structure consisting of the oxygen barrier resin layer 4 and the outer second water vapor barrier resin layer 6 are prepared, and melted polyethylene or the like The paper material and the film can be laminated by extrusion lamination using a thermoplastic resin (water vapor barrier resin). In this case, the polyethylene or the like used for extrusion lamination is the first water vapor barrier resin layer 5 that is the innermost layer of the synthetic resin layer 3. By manufacturing by extrusion lamination, a fibrous casing excellent in processing suitability such as printability and bag-making suitability can be obtained. In the case of extrusion lamination, elution of resin components and the like can be reduced as compared with dry lamination.

  Prior to laminating, corona treatment is preferably performed on the surface of the paper material on which the synthetic resin layer is laminated. By performing the corona treatment, the wettability of the surface is increased and the adhesion between the paper layer 2 and the synthetic resin layer 3 can be increased.

  After laminating, the fiber casing 1 can be obtained by impregnating the paper material forming the paper layer 2 with a food modifier. The method for impregnating the food modifier is not particularly limited, and may be performed by coating or dipping.

<Other embodiments>
The fibrous casing of the present invention is not limited to the above embodiment. For example, the synthetic resin layer is not limited to the above three-layer structure. The synthetic resin layer may be a single layer composed of an oxygen barrier resin layer or a water vapor barrier resin layer, or may have a layer structure of two layers or four layers or more. When the synthetic resin layer has a plurality of oxygen barrier resin layers or water vapor barrier resin layers, the stacking order of the layers is not particularly limited. However, in order to satisfactorily exhibit both the oxygen barrier function and the water vapor barrier function, it is preferable to alternately stack a total of three or more oxygen barrier resin layers and water vapor barrier resin layers.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

  In addition, each measured value in a present Example is a value measured with the following method.

<Basis weight>
The basis weight (g / m ² ) was measured according to JIS-P-8124 (2011) “Paper and paperboard—Method for measuring basis weight”.

<Paper thickness>
Paper thickness (micrometer) was measured based on JIS-P-8118 (1998) "Paper and paperboard-Test method of thickness and density".

<Arithmetic mean roughness Ra>
The arithmetic average roughness Ra (μm) was measured at a cutoff λc of 2.5 mm and an evaluation length of 12.5 mm in accordance with JIS-B-0601 (2001).

[Example 1]
A pulp slurry was prepared by adding 3 parts by mass of a wet paper strength agent in terms of solid content to pulp (absolutely dry amount) to 85% softwood bleached kraft pulp (NBKP) and 15% mercerized pulp.

Next, this pulp slurry was paper-made with a circular paper machine equipped with a Yankee dryer, and a fibrous casing paper material of Example 1 was obtained. The basis weight of the fiber casing paper material is 18.3 g / m ² , the paper thickness is 40 μm, the arithmetic average roughness Ra (glossy surface) is 1.8 μm, and the arithmetic average roughness (non-glossy surface) is 4.3 μm. Met.

[Examples 2 to 4, Comparative Examples 1 and 2]
Paper materials of Examples 2 to 4 having the paper thickness and surface roughness shown in Table 1 were obtained under the same conditions as in Example 1 except that papermaking and drying conditions were adjusted. Moreover, each paper material of the comparative example 1 which made the both surfaces the glossy surface, and the comparative example 2 which made the both surfaces non-glossy was obtained.

  The glossy surface of each paper material (Comparative Examples 1 and 2 is one surface) is corona-treated, and a polyethylene layer (15 μm) as a first water vapor barrier resin layer and an oxygen barrier resin layer are formed on the treated surface side. A synthetic resin layer having a three-layer structure of a nylon layer (15 μm) and a polyethylene layer (20 μm) as a second water vapor barrier resin layer was laminated. This lamination was performed by extrusion lamination of polyethylene serving as the first water vapor barrier resin layer to obtain a fibrous casing.

With respect to each of the obtained fibrous casings, the liquid retaining property (liquid retaining amount) and the releasing property of the food modifier were evaluated by the following methods. The evaluation method is as follows. The evaluation results are shown in Table 1.
(1) Liquid retention amount (liquid retention)
A desired amount of a liquid (Kerry's “Super Smoke 330”) was charged into a fiber casing (folded diameter: 135 mm), and wound with a winding device at a drawing pressure of 2 bar and a speed of 30 m / min. The liquid retention amount was calculated from the mass change per unit area of the fiber casing, and evaluated according to the following criteria.
◎: Liquid retention amount is 13.0 g / m ² or more ○: Liquid retention amount is 11.0 g / m ² or more and less than 13.0 g / m ² ×: Liquid retention amount is less than 11.0 g / m ² (2) Food Release of modifier (transferability to food)
The processed meat product was cooked by boiling for 1 hour in a 80 ° C water bath in a fiber casing in which the liquid layer (Kerry's “Super Smoke 330”) was impregnated with a paper layer of 11 to 13 g / m ² (actual value). Then, the fibrous casing was peeled off. The mass of the fiber casing before impregnation of the liquid smoke (M1), the mass of the fiber brass casing after the liquid immersion (M2), and the mass of the fiber casing after the liquid transfer (release) (M3) are measured. From the value, the release rate of the liquid smoke (food modifier) was calculated by the following formula. Release properties were evaluated according to the following criteria.
Release rate (%) = 100 × (M2-M3) / (M2-M1)
◎: Release rate is 90% or more ○: Release rate is 50% or more ×: Release rate is less than 50%

  As shown in Table 1 above, each of the brass casings of Examples 1 to 4 was excellent in the liquid retaining property of the food modifier and the release property of the food modifier was also good. In Example 2, the release property was slightly inferior to the other examples, probably because the surface roughness of the inner surface (non-glossy surface) was slightly small. In Example 3, the surface roughness of the inner surface (non-glossy surface) was large and the release property was sufficient, but after the release property evaluation test, the pulp stuck to the food. In Example 4, the surface roughness of the outer surface was slightly large, and the liquid retention amount was slightly small, probably because the resin was easily impregnated into the paper layer during lamination.

  On the other hand, both sides of Comparative Example 1 were glossy, and the liquid retention amount and the release property of the food modifier were low. By making both sides glossy, it is assumed that the paper thickness is reduced and the amount of liquid retained is reduced, and that the inner surface is glossy, the release is reduced.

  The comparative example 2 whose both surfaces are non-glossy also had a low liquid retention amount and release property of the food modifier. When the outer surface of the paper layer is a non-glossy surface, the outer synthetic resin layer is impregnated into the paper layer, so that it is assumed that the reason is that the liquid retaining thickness of the paper layer is reduced. Further, from the comparison between Example 1 and Comparative Example 2, by making the outer surface of the paper layer a glossy surface, the barrier function of the outer surface of the paper layer is increased, and the release of the food modifier to the inner surface side is increased. Recognize.

  As described above, the fibrous casing of the present invention can be used as a packaging sheet for heat cooking to be transferred to livestock meat such as ham, sausage, cheese, and processed food products.

DESCRIPTION OF SYMBOLS 1 Five casing 2 Paper layer 2a Inner surface 2b Outer surface 3 Synthetic resin layer 4 Oxygen barrier resin layer 5 1st water vapor barrier resin layer 6 2nd water vapor barrier resin layer

Claims (5)

A brass casing used as a food packaging material during heat treatment of food,
It is arranged as the innermost layer and comprises a paper layer formed from a paper material mainly composed of pulp, and a synthetic resin layer laminated on the outer surface of this paper layer,
A fibrous casing, wherein the inner surface of the paper material is a non-glossy surface and the outer surface is a glossy surface.   The fibrous casing according to claim 1, wherein the synthetic resin layer includes an oxygen barrier resin layer having an oxygen barrier property and a water vapor barrier resin layer having a water vapor barrier property.   The fiber casing according to claim 2, wherein the resin forming the oxygen barrier resin layer is nylon, and the resin forming the water vapor barrier resin layer is polyethylene. The paper layer includes a food modifier impregnated in the paper material;
The fibrous casing according to claim 1 , wherein the food modifier contains a pigment, a fragrance, or a combination thereof. A method for manufacturing a fibrous casing used as a food packaging material during heat treatment of food,
The above-mentioned brass casing is disposed as an innermost layer, and includes a paper layer formed from a paper material mainly composed of pulp, and a synthetic resin layer laminated on the outer surface of the paper layer,
The inner surface of the paper material is a non-glossy surface, the outer surface is a glossy surface,
The innermost layer of the synthetic resin layer is a water vapor barrier resin layer having a water vapor barrier property,
Step of laminating the synthetic resin layer on the outer surface of the paper layer by extrusion lamination of the resin that forms the water vapor barrier resin layer
A method for manufacturing a fibrous casing, comprising:

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