JP2017112869A - Fibrous casing paper material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fibrous casing paper material that can obtain a fibrous casing superior in liquid retention and releasing property of food modifiers, etc., as well as folding process suitability.SOLUTION: A fibrous casing paper material of the present invention is used as a food packaging material in the heat treatment of food, and comprises natural pulp fibers being chief ingredients and rayon fibers, in which one surface is a glossy surface and the other surface is a non-glossy surface. In the fibrous casing paper material, it is preferable that a water absorption amount from the glossy surface is 20 ml/mor more and 70 ml/mor less, and the water absorption amount from the non-glossy surface is 10 ml/mor more and 60 ml/mor less, in the speed setting of 50.0 mm/s and the contact time of 20 seconds by the Bristow method. Preferably, the arithmetic average roughness Ra of the glossy surface is 0.5 μm or more and less than 4 μm, and the arithmetic average roughness Ra of the non-glossy surface is 4 μm or more and 8 μm or less.SELECTED DRAWING: None

Description

  The present invention relates to a fiber casing paper material.

  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 the fibrous casing having such a layer structure, those in which paper and a heat-sealable nonwoven fabric are laminated, those having an inner layer made of fibers, etc., and an outer layer made of a film having gas barrier properties have been developed. (See JP-A-6-31494 and JP-A-2000-116365). Also, as a fiber casing with improved peelability, a soot treatment wrapping paper having a release layer formed by a coating liquid containing a silicone resin on the inner surface side of the base paper has been proposed. A glossy paper is also used as the base paper (see Japanese Patent Application Laid-Open No. 2015-001037).

  Here, the fibrous casing can hold a sufficient amount of the food modifier in the inner layer, and is required to have a function of efficiently releasing the food modifier for the packaged food. . However, the conventional fibrous casing in which general paper or the like is used as the inner layer does not have sufficient liquid absorbency and dischargeability of the inner layer. Furthermore, when the release layer is provided on the inner surface like the release paper for smoke treatment, the liquid absorbency is further lowered. On the other hand, it is also conceivable to increase the thickness of the inner layer in order to increase the liquid absorption. However, simply increasing the thickness of the inner layer has the disadvantage that it is difficult to fold the fibrous casing.

JP-A-6-31494 JP 2000-116365 A Japanese Patent Laying-Open No. 2015-001037

  The present invention has been made based on such circumstances, and an object of the present invention is to obtain a fiber casing excellent in liquid retention and release properties of food modifiers, etc., and folding processability. It is to provide a fiber casing paper material.

  The present invention made to solve the above problems is a paper material for a fiber casing used as a food packaging material in the heat treatment of food, comprising a natural pulp fiber as a main component and a rayon fiber. One of the surfaces is a glossy surface and the other surface is a non-glossy surface.

  The fibrous casing paper material (hereinafter also simply referred to as “paper material”) is used as the innermost layer of the fibrous casing, for example, such that the non-glossy surface becomes the inner surface (the surface in contact with food). By using the paper material, which is glossy paper containing rayon fibers, in this way, it is possible to improve the liquid retention and release properties of food modifiers and the like of the fiber casing. In addition, since the paper material includes bulky and low-rigidity rayon fibers, the paper material is highly flexible and can improve the suitability of folding of the resulting fibrous casing.

The water absorption amount from the glossy surface when the speed is set to 50.0 mm / s by the Bristow method and the contact time is 20 seconds in the fibrous casing paper material is 20 ml / m ² or more and 70 ml / m ² or less, from the non-glossy surface. The water absorption is preferably 10 ml / m ² or more and 60 ml / m ² or less. Thereby, food modifier etc. can be more fully impregnated, and this food modifier etc. can be discharged suitably.

  The arithmetic average roughness Ra of the glossy surface is preferably 0.5 μm or more and less than 4 μm, and the arithmetic average roughness Ra of the non-glossy surface is preferably 4 μm or more and 8 μm or less. Thereby, liquid retention property and discharge | release properties, such as a food modifier, can be improved more.

  The absolute value of the fiber orientation angle of the glossy surface is 0 ° or more and 3 ° or less, and the absolute value of the fiber orientation angle of the non-glossy surface is 0.5 ° or more and 4 ° or less. The fiber orientation angle of the glossy surface Is preferably smaller than the absolute value of the fiber orientation angle of the non-glossy surface. Thereby, the orientation of the fiber on the glossy surface is dense and uniform, and the release property of the food modifier or the like to the non-glossy surface side can be further enhanced. Moreover, the liquid retention property and discharge | release property when a non-glossy surface is made into an inner surface can be improved more according to the relatively random fiber orientation in a non-glossy surface.

  As content with respect to all the fiber components of the said rayon fiber, 5 to 45 mass% is preferable. Thereby, liquid retention property, discharge | release property, folding process aptitude, etc. can be improved, maintaining sufficient peelability.

  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 less than 4 μm. “Non-glossy surface” refers to a surface having no gloss and an arithmetic average roughness Ra of 4 μm or more.

  As described above, the fibrous casing paper material of the present invention can provide a fibrous casing that is excellent in liquid retention and release properties such as food modifiers and folding processability.

(Fibrous casing paper material)
The fibrous casing paper material according to an embodiment of the present invention includes natural pulp fibers as main components and rayon fibers, one surface being a glossy surface and the other surface being a non-glossy surface. The paper material is usually used as a material for forming the innermost layer of a fiber casing used as a food packaging material in the heat treatment of food. In this fiber casing, a synthetic resin layer as an outer layer is generally laminated on the glossy surface side of the paper material (paper layer) as an inner layer.

  In this way, when the paper material is used, the inner surface of the inner layer of the fibrous casing becomes a non-glossy surface, so that the surface area is widened, and the liquid retention and release properties can be improved. That is, in the fibrous casing, the paper layer (inner layer) formed from the paper material can absorb a sufficient amount of the food modifier. Can be released (transferred) efficiently. On the other hand, the outer surface of the inner layer is a glossy surface, and on this glossy surface, pulp fibers are bonded to each other and there are few voids. For this reason, the food modifier impregnated from the inner surface side cannot be impregnated to the vicinity of the outer surface in the inner layer, and the release property of the food modifier to the inner surface side is increased during cooking. Furthermore, by making the glossy surface the outer surface, for example, when a synthetic resin layer is laminated on the outer surface of the paper material by extrusion lamination, the resin forming the synthetic resin layer is less likely to be impregnated in the paper material. Therefore, according to the paper material, the thickness of the inner 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. Furthermore, since the paper material contains rayon fibers having high hydrophilicity, it is possible to improve liquid retention properties. In addition, since rayon fibers are bulky and low in rigidity, the paper material is highly flexible, and the suitability for folding of the resulting fibrous casing can be enhanced.

  The lower limit of the content of the fiber component (natural pulp fiber, rayon fiber and other fiber components) in the paper material is usually 50% by mass, preferably 80% by mass, more preferably 90% by mass. 95 mass% is more preferable. By setting the content of the fiber component to the above lower limit or more, the liquid retention property, the release property, the flexibility, etc. can be more fully exhibited.

  The paper material is usually obtained by papermaking a pulp slurry containing natural pulp (natural pulp fiber) and rayon pulp (rayon fiber).

  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). The strength is increased by using softwood bleached kraft pulp (NBKP) as the natural pulp. In addition, since NBKP has a large fiber diameter and long fibers, the paper material has a large gap and is more easily impregnated with a food modifier or the like.

  The natural pulp fiber is the main component of the paper material. As a minimum of content of natural pulp fiber to all fiber constituents which form the paper material, 50 mass% is preferred, 55 mass% is more preferred, 60 mass% is still more preferred, and 70 mass% is especially preferred. On the other hand, as an upper limit of this content, 95 mass% is preferable, 90 mass% is more preferable, 85 mass% is further more preferable. By setting the content of the natural pulp fiber within the above range, better liquid retention and release properties can be exhibited.

  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 retention property, the release property, etc. 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).

  The rayon fiber is a kind of regenerated fiber produced using cellulose such as pulp as a raw material, and is a fiber having high hydrophilicity. The rayon fiber usually has a large surface area and is bulky and flexible because a plurality of linear protrusions along the fiber axis direction are formed on the surface in the manufacturing process. Accordingly, by mixing the rayon fiber together with the natural pulp fiber, it is possible to enhance the liquid retention property, the release property and the folding processability.

  As the rayon fiber, known products such as commercially available products can be used. The fineness of the rayon fiber can be set to, for example, 0.1 dtex or more and 10 dtex or less from the viewpoint of sufficiently exhibiting the folding processability. Moreover, as an average fiber length of the said rayon fiber, it can be set as 1 mm or more and 10 mm or less, for example. The fineness refers to a value measured according to JIS-L-1095 (2010) “General Spinning Test Method”. The average fiber length refers to the number average fiber length measured according to JIS-P-8226 (2006) “Pulp—Average fiber length measurement method by optical automatic analysis—Part 1: Polarization method”.

  The lower limit of the rayon fiber content with respect to all fiber components forming the paper material is preferably 5% by mass, more preferably 10% by mass, and even more preferably 20% by mass. On the other hand, as an upper limit of this content, 45 mass% is preferable, 40 mass% is more preferable, and 30 mass% is further more preferable. By setting the content of the rayon fiber to the above lower limit or more, it is possible to further improve the liquid retention property, the release property, the folding processability, and the like. On the other hand, when the content of rayon fiber exceeds the above upper limit, a large amount of rayon fiber tends to stick to the food as the content, and the peelability may be lowered.

  In the said paper raw material, fiber components other than the said natural pulp fiber and rayon fiber can be contained. Examples of other fiber components include polyolefin fibers, polyester fibers, 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 the total fiber component in the paper material 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 relative to 100 parts by mass of the total fiber component is preferably 6 parts by mass, more preferably 5.5 parts by mass, and even more preferably 5 parts by mass. By setting the content of the wet paper strength agent to the above lower limit or more, the peelability from food (contents) can be sufficiently improved. In addition, when content of the said wet paper strength agent exceeds the said upper limit, there exists a possibility that liquid retention may fall.

  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 relative to 100 parts by mass of the total fiber component in the paper material is preferably 0.2 parts by mass, more preferably 0.5 parts by mass, and 1 part 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 the total fiber component is preferably 5.5 parts by mass, more preferably 5 parts by mass, and further 4.5 parts by mass. preferable. By setting the content of the dry paper strength enhancer to the above lower limit or more, the peelability from the food (content) can be sufficiently improved. In addition, when content of the said dry paper strength enhancer exceeds the said upper limit, there exists a possibility that liquid retention property may fall.

  The paper material preferably contains a sizing agent as an additive. Since the paper material contains a sizing agent, it is possible to improve heat retaining properties, heat insulating properties, glossy surface smoothness, and the like. 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 sufficiently improve the smoothness of the glossy surface when one surface of the paper material is formed on the 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.

  The lower limit of the content of the sizing agent (in terms of solid content) relative to 100 parts by mass of the total fiber component in the paper material is preferably 1 part by mass, more preferably 1.5 parts by mass, and even more preferably 1.7 parts by mass. . On the other hand, the upper limit of the content of the sizing agent (in terms of solid content) relative to 100 parts by mass of the total fiber component is preferably 3 parts by mass, more preferably 2.5 parts by mass, and even more preferably 2.3 parts by mass. 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 may be lowered and the operability may be lowered.

  The paper material may contain other additives as long as the object of the present invention is not impaired. 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 arithmetic average roughness Ra of the glossy surface 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 arithmetic average roughness Ra of the glossy surface is less than 4 μm, preferably 3.8 μm or less, may be 3.5 μm or less, and may be 3 μm or less. By setting the arithmetic average roughness Ra of the glossy surface in the above range, when the glossy surface is the outer surface, it is possible to enhance the releasability of the food modifier or the like on the inner surface side, the liquid retention property, and the like. When the arithmetic average roughness Ra of the glossy surface is a rough surface exceeding the above upper limit, the release property of the food modifier or the like impregnated from the inner surface side to the inner surface side decreases. Moreover, when the arithmetic average roughness Ra of the glossy surface that is the outer surface is a rough surface that exceeds the above upper limit, when the synthetic resin layer is laminated on the outer surface side, the amount of impregnation from the outer surface side of the resin increases, and the liquid retaining property (Amount of liquid that can be retained) decreases.

  The lower limit of the arithmetic average roughness Ra of the non-glossy surface is 4 μm, preferably 4.5 μm, and may be 5 μm. On the other hand, the upper limit of the arithmetic average roughness Ra of the non-glossy surface may be 10 μm, preferably 8 μm, and more preferably 7 μm. By setting the arithmetic average roughness Ra of the non-glossy surface to the above range, when the non-glossy surface is the inner surface, the release property and liquid retention of the food modifier and the like can be suitably enhanced. When the arithmetic average roughness Ra of the non-glossy surface that is the inner surface is a smooth surface that is less than the above lower limit, the surface area is reduced, and the release properties and liquid retention properties of food modifiers and the like are reduced. On the other hand, when the arithmetic average roughness Ra of the non-gloss surface serving as the inner surface exceeds the above upper limit, the paper material tends to stick to the food, and the peelability to the food decreases.

  The lower limit of the rigidity of the paper material is preferably 40 mm, and more preferably 45 mm. On the other hand, the upper limit is preferably 80 mm. By setting the rigidity of the paper material in the above range, the suitability for folding can be further improved. This rigidity can be adjusted by the content of natural pulp fibers, the content of rayon fibers, the basis weight, the density, various kinds of chemicals added and the amount added, and the like in the paper material. If the rigidity is less than 40 mm, the rigidity is too high and the suitability of the fiber casing paper material is deteriorated. If the rigidity is more than 80 mm, the rigidity is too weak and the suitability for bag making is deteriorated and cannot be used. is there. In addition, the rigidity of the paper material refers to a numerical value measured by the measuring method described in the examples.

Speed Setting 50.0 mm / s by the Bristow method, the lower limit of the water absorption from the gloss surface of a contact time of 20 seconds, preferably 20 ml / ^{m 2,} more preferably ^{30ml / m 2, 40ml / m} 2 and more preferable. In contrast, the upper limit of the water absorption from the gloss surface at speed setting 50.0 mm / s, contact time 20 seconds by the Bristow method, is preferably 70 ml / ^{m 2,} more preferably ^{68ml / m 2, 65ml / m} 2 Is more preferable. The lower limit of the water absorption amount from the non-gloss surface at a rate set 50.0 mm / s, contact time 20 seconds by the Bristow method, is preferably 10 ml / ^{m 2,} more preferably 20ml / ^{m 2,} 30ml / ^{m 2} is more preferable, and 40 ml / m ² is particularly preferable. In contrast, the upper limit of the water absorption amount from the non-gloss surface at a rate set 50.0 mm / s, contact time 20 seconds by the Bristow method is preferably 65 ml / ^{m 2,} more preferably 63ml / ^{m 2,} 60ml / ^{m 2} is more preferable. Furthermore, it is preferable that the water absorption amount from the glossy surface when the speed setting by the Bristow method is 50.0 mm / s and the contact time is 20 seconds is larger than the water absorption amount from the non-glossy surface. The paper material is sufficiently impregnated with a food modifier, etc., because the water absorption from the glossy surface and non-glossy surface is within the above range at a speed setting of 50.0 mm / s by the Bristow method and a contact time of 20 seconds. The food modifier and the like can be suitably released.

  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) and the fiber orientation angle of the non-glossy surface (inner surface) are within the above range, so that the fiber orientation on the glossy surface is dense and uniform. It is possible to enhance the liquidity and the releasability of the food modifier from the non-glossy surface.

The lower limit of the basis weight of the paper material is 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 material is preferably 30 g / ^{m 2,} more preferably ^{28g / m 2, 25g / m} 2 is more preferred. When the basis weight is less than the lower limit, the strength of the paper material may be reduced and the paper material may be easily broken, or the liquid retention may be reduced. On the other hand, when the basis weight exceeds the upper limit, the rigidity of the paper material is increased, so that the suitability for folding process is lowered, and it may be 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 material, preferably from ^{0.15g / cm 3, 0.2g / cm} 3 is more preferable. On the other hand, the upper limit of the density of the paper material, preferably from ^{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 heat insulating property may be lowered. On the contrary, when the density exceeds the upper limit, the rigidity of the paper material is increased, so that the suitability for folding process is lowered, and it is difficult to deform along the shape of the contents. Moreover, when the said density exceeds the said upper limit, the space | gap between fibers becomes small or decreases, and there exists a possibility that liquid retention may fall. 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 wet tensile strength in the longitudinal direction is less than the lower limit, the peelability from the contents may be reduced.

  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 100 μm, more preferably 90 μm, 80 μm, 70 μm and 60 μm in this order, and particularly preferably 50 μm. When the paper thickness is less than the lower limit, liquid retention and liquid retention may be reduced. On the other hand, when the paper thickness exceeds the upper limit, the folding processability and the like may be reduced.

(Manufacturing method of fiber casing paper material)
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 obtained by adding various additives as necessary to a pulp slurry containing natural pulp fibers and rayon fibers, a wire part, a press part, a Yankee dryer, a calendar part, etc. The paper-making method is mentioned with the normal paper machine provided with. 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.

(How to use the fiber casing paper material)
The paper material is suitably used as a material for forming an inner layer of a fibrous casing having a layer structure of an inner layer and an outer layer. At this time, a synthetic resin layer as an outer layer is usually laminated on the glossy surface side of the paper material. Hereinafter, a fiber casing having a layer structure of an inner layer and an outer layer, the inner layer being formed from the paper material, and the outer layer being a synthetic resin layer will be described.

  The inner layer is a paper layer formed from the paper material. This inner layer (paper layer) 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 includes, for example, an oxygen barrier resin layer, a first water vapor barrier resin layer stacked on the inner surface of the oxygen barrier resin layer, and a second layer stacked on the outer surface of the oxygen barrier resin layer. It can be set as the three-layer structure which has a water vapor | steam barrier resin layer. When the synthetic resin layer has an oxygen barrier resin layer, it is possible to effectively cook food and transfer the food modifier to the food at this time. In addition, the synthetic resin layer has the first water vapor barrier resin layer and the second water vapor barrier resin layer, so that cooking of food and transfer of the food modifier to the food at this time are effective. Can be done automatically. Moreover, the preservability of foodstuffs etc. increase by providing these layers.

  Examples of the resin forming the oxygen barrier resin layer 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. of the oxygen barrier resin layer, 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 is within the above range, good food storage stability, heat cooking property and the like can be exhibited.

  As the oxygen barrier resin layer, a heat shrinkable film (shrink film) formed by stretching a film formed from the resin is usually used. The heat shrink temperature of the oxygen barrier resin layer (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.

  The average thickness of the oxygen barrier resin layer 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 oxygen barrier property etc. and workability etc. can be aimed at.

  Examples of the resin forming the first water vapor barrier resin layer and the second water vapor barrier resin layer 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 and the resin forming the second water vapor barrier resin layer may be of the same type or different types.

20 ° C. above the water vapor barrier resin layer, the upper limit of water vapor 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 water vapor permeability of the water vapor barrier resin layer is within the above range, good food preservability, heat cooking property and the like can be exhibited.

  The average thickness of the first water vapor barrier resin layer and the second water vapor barrier resin layer 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 and the second water vapor barrier resin layer is not particularly limited. For example, it may be formed by coating on an oxygen barrier resin layer, or the water vapor barrier resin layer may be bonded to the oxygen barrier resin layer as a film made of a single layer of water vapor barrier resin. Further, as will be described later, the first water vapor barrier resin layer in contact with the inner layer (paper material) may be formed during extrusion lamination.

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

  Although it does not specifically limit as a manufacturing method of the said brass casing, It can manufacture efficiently by lamination processes, such as dry lamination and extrusion lamination. In the case of producing by dry lamination, the paper material that becomes an inner layer (paper layer) and a film having a three-layer structure that becomes a synthetic resin layer are stacked and dry laminated. In the case of manufacturing by extrusion lamination, a melted polyethylene is prepared by preparing a paper material to be an inner layer (paper layer) and a film having a two-layer structure including an oxygen barrier resin layer and an outer second water vapor barrier resin layer. The paper material and the film can be laminated by extrusion lamination using a thermoplastic resin such as a water vapor barrier resin. In this case, the polyethylene or the like used for extrusion lamination is the first water vapor barrier resin layer that is the innermost layer of the synthetic resin layer. 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 inner layer and the synthetic resin layer can be increased.

  After laminating, a fiber casing can be obtained by impregnating the paper material forming the inner layer 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 paper material of the present invention is not limited to the above embodiment. For example, the paper material may be used for the inner layer of the fibrous casing with the non-glossy side as the outer surface and the glossy side as the inner surface. In this case, when the inner surface is a glossy surface, it is possible to enhance the peelability of the food as the contents. Moreover, adhesiveness with a synthetic resin layer can be improved with an anchor effect etc. because an outer surface is a non-glossy surface. Further, in the fibrous casing using the paper material, the synthetic resin layer provided as the outer 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".

<Rigidity>
The rigidity is determined by hanging a test piece obtained by cutting a fibrous casing paper material in a width direction of 30 mm and a flow direction of 100 mm from the edge of the horizontal test bench and pulling the upper end of the test piece along the surface of the test bench. Gradually increased. The angle between the test piece and the test stand (surface) was measured with a protractor, and the length of the test piece pulled up when it reached 45 degrees was measured with a ruler.

<Water absorption (Bristow method)>
The amount of water absorption (ml / m ² ) was measured according to the Bristow method, with a contact time of 20 seconds at a speed setting of 50.0 mm / s. Each of the water absorption from the glossy surface and the water absorption from the non-glossy surface was measured.

<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).

<Fiber orientation angle>
The fiber orientation angle (°) was measured with an optical orientation tester manufactured by Toyo Seiki Seisakusho Co., Ltd., and the absolute value of the obtained value was defined as the fiber orientation angle.

[Example 1]
A pulp slurry was prepared by adding 3 parts by weight of a wet paper strength agent in terms of solid content to pulp (absolute dry weight) to 80% by weight of softwood bleached kraft pulp (NBKP) and 20% by weight of rayon fiber. .

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. In addition, the basis weight of the fiber casing paper material is 17.0 g / m ² , the paper thickness is 38 μm, the rigidity is 50 mm, the water absorption (glossy surface) is 50 ml / m ² , and the water absorption (non-glossy surface) is 47 ml / m. ^2. Arithmetic average roughness Ra (glossy surface) is 3.4 μm, arithmetic average roughness (non-glossy surface) is 3.6 μm, fiber orientation angle (glossy surface) is 2.7 °, fiber orientation angle (non-glossy surface) ) Was 3.6 °.

[Examples 2 to 4, Comparative Examples 1 to 5]
The mixing ratio of the pulp fiber types is as shown in Table 1, except that the papermaking and drying conditions were adjusted, and the conditions of Examples 2 to 4 and Comparative Examples 1 to 3 described in Table 1 were the same as in Example 1. Obtained paper material. Moreover, each paper material of the comparative example 4 which made the both surfaces the glossy surface, and the comparative example 5 which made the both surfaces non-glossy was obtained.

  The glossy surface of each paper material (Comparative Examples 4 and 5 is one surface) is corona-treated, and on the treated surface side, a polyethylene layer (15 μm) as a first water vapor barrier resin layer and an oxygen barrier resin layer 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 brass casings, the liquid retainability (liquid retention amount), the release property and the folding processability 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) Release of food 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 and less than 90% ×: Release rate is less than 50%

(3) Folding suitability A 100 mm × 100 mm bag-making sample was prepared by three-side sealing a fibrous casing paper material with a thermal inclination tester at a temperature of 160 ° C., a pressure of 3 kg / cm ² , and a sealing time of 2 seconds. The presence or absence of tearing of the bag-making sample at that time was confirmed visually.
(Double-circle): There was no torn sample in 50 bag-making samples, and folding processability was favorable.
○: Among the 50 bag-making samples, 1 to 2 samples were torn and suitability for folding.
X: There were 3 or more torn samples out of 50 bag-making samples, and there was no suitability for folding.

  As shown in Table 1 above, each of the brass casings of Examples 1 to 4 was excellent in the liquid absorbency of the food modifier, and had good food modifier release properties and folding processability.

  On the other hand, the comparative example 1 which did not use the rayon fiber had too high rigidity, and its liquid retention property and folding processability were low. Further, Comparative Examples 2 and 3, which did not contain NBKP as a main component, had too low rigidity, and all of the liquid retention property, release property, and folding processability were low. In Comparative Example 4, both surfaces were glossy, and the liquid retention property, release property and folding processability 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 retention is reduced, and that the inner surface is glossy, the liquid retention, release and folding processability are reduced. In Comparative Example 5 where both surfaces are non-glossy, the liquid retention and release properties of the food modifier were also low. 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.

  As described above, the fibrous casing paper material of the present invention can be used as a material for an inner layer of a fibrous casing (packaging sheet for cooking) that is transferred to livestock meat such as ham, sausage, cheese, and processed food products.

Claims (5)

A paper material for a brass casing used as a food packaging material in the heat treatment of food,
Including natural pulp fiber as the main component and rayon fiber,
A fibrous casing paper material, wherein one surface is a glossy surface and the other surface is a non-glossy surface. The water absorption from the glossy surface is 20 ml / m ² or more and 70 ml / m ² or less, and the water absorption from the non-glossy surface is 10 ml / m ^{2 at} a speed setting of 50.0 mm / s by the Bristow method and a contact time of 20 seconds. The fibrous casing paper material according to claim 1, wherein the material is 60 ml / m ² or less.   3. The fibrous casing paper material according to claim 1, wherein the glossy surface has an arithmetic average roughness Ra of 0.5 μm or more and less than 4 μm, and the non-glossy surface has an arithmetic average roughness Ra of 4 μm or more and 8 μm or less.   The absolute value of the fiber orientation angle of the glossy surface is 0 ° or more and 3 ° or less, the absolute value of the fiber orientation angle of the non-glossy surface is 0.5 ° or more and 4 ° or less, and the absolute value of the fiber orientation angle of the glossy surface is The fiber casing paper material according to claim 1, wherein the value is smaller than an absolute value of the fiber orientation angle of the non-glossy surface. The fiber casing paper material according to any one of claims 1 to 4, wherein the content of the rayon fiber with respect to all fiber components is 5 mass% or more and 45 mass% or less.