Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/10—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of paper or cardboard
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B29/00—Layered products comprising a layer of paper or cardboard
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
  • B65D65/38—Packaging materials of special type or form
  • B65D65/40—Applications of laminates for particular packaging purposes
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
  • D21H27/10—Packing paper
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
  • D21H27/30—Multi-ply

Definitions

• the present invention relates to a flexible packaging paper and a flexible packaging using the same.
• Patent Documents 1 and 2 propose the use of heat-seal paper in which a heat-seal layer is laminated on a paper base material as a packaging material. Depending on the type of heat-sealable resin, these are decomposed in the environment, so the environmental load can be significantly reduced.
• heat-seal paper has significantly different physical properties compared to plastic film, so if heat-seal paper is passed through a bag-making machine under the same operating conditions as plastic film, the paper may meander, break, or become unusable. In some cases, problems such as bending or wrinkles occur in the soft packaging, or the inability to form bags in the desired shape, necessitate optimizing operating conditions such as slowing down the line speed.
• An object of the present invention is to provide a flexible packaging paper that can be made into bags using a bag-making machine, and a flexible packaging using this flexible packaging paper.
• Means for solving the problems of the present invention are as follows. 1. having a paper base material and a heat sealing layer on at least one outermost surface, The paper base material has a thickness of 25 ⁇ m or more and 100 ⁇ m or less, The ratio of pulp to the total papermaking fibers contained in the paper base exceeds 90% by weight, A flexible packaging paper characterized by satisfying any one or more of the following conditions (1) to (4).
• the bending hysteresis 2HB in the MD direction by the KES method is 0.02 g ⁇ cm/cm or more and 1.2 g ⁇ cm/cm or less
• the bending rigidity B in the MD direction by the KES method is 0.16 g ⁇ cm 2 /cm or more and 1.8g ⁇ cm 2 /cm or less
• the other surface of the paper base material is exposed, and the smoothness of the exposed surface (Oken type) is 50 seconds or more and 700 seconds or less
• Young's modulus in the MD direction is 3 GPa or more and 15 GPa or less.
• the paper base material has a basis weight of 20 g/m 2 or more and 70 g/m 2 or less. Flexible packaging paper described in .
• the paper base material has a density of 0.5 g/cm 3 or more and 0.95 g/cm 3 or less. or 2.
• the item to be packaged is 1. ⁇ 3.
• a flexible packaging body characterized by being enclosed in a packaging material made of the flexible packaging paper according to any one of the above.
• the flexible packaging paper of the present invention can be used as a substitute for conventional packaging materials made of resin films.
• the flexible packaging paper of the present invention can be passed through a bag making machine under the same operating conditions as conventional plastic films to produce flexible packaging. Since there is no need to change operating conditions, it is easy to switch between the resin film and the flexible packaging paper of the present invention to produce flexible packaging made of different materials. Since the flexible packaging paper of the present invention is mainly made of paper, the amount of resin material used can be significantly reduced.
• Flexible packaging paper The flexible packaging paper of the present invention has a paper base material and a heat seal layer on at least one outermost surface.
• the paper base material is a base material on which a heat seal layer is formed on at least one surface.
• the paper base material is a sheet mainly made of pulp, and the base paper obtained by making paper from paper stock containing pulp, fillers, various auxiliary agents, etc. is used as it is, or on at least one side of the base paper, a sealing layer and ink are applied.
• One or more functional layers such as a receptor layer, a water-resistant layer, an oil-resistant layer, a water vapor barrier layer, a gas barrier layer, etc. can be used.
• Pulps include chemical pulps such as hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), softwood unbleached pulp (NUKP), sulfite pulp, stone grind pulp, and thermoplastic pulp.
• Mechanical pulp such as mechanical pulp, wood fibers such as deinked pulp and waste paper pulp, non-wood fibers obtained from kenaf, bamboo, hemp, etc. can be used, and two or more types can also be used in combination. Among these, it is difficult to cause foreign matter to be mixed in, it is difficult to discolor over time when recycled by using it as a waste paper material after use, and it has a high degree of whiteness, so it has a good surface feel when printing.
• the amount of chemical pulp of wood fibers such as LBKP and NBKP relative to the total pulp is preferably 80% by weight or more, more preferably 90% by weight or more, and even more preferably 95% by weight or more. , more preferably 98% by weight or more, and even more preferably 100% by weight.
• the blending ratio of hardwood pulp in the pulp is preferably 30% by weight or more, more preferably 50% by weight or more.
• the freeness of the pulp (Canadian standard freeness: CSF) is preferably 600 ml or less, more preferably 550 ml or less, and 500 ml or less from the viewpoint of the strength of the paper base material. More preferred.
• the paper base material of the present invention can contain paper-making fibers other than pulp, the ratio of pulp to the total paper-making fibers contained in the paper base material exceeds 90% by weight.
• fibers other than pulp include thermoplastic resin fibers. Since thermoplastic resin fibers have heat-sealing properties, a paper base material containing thermoplastic resin fibers has excellent heat-sealing strength because the paper base material and the heat-sealing layer are firmly adhered to each other during heat-sealing.
• thermoplastic resin fibers those used in the paper manufacturing field can be used without particular limitation, but examples include PVA, polylactic acid, polybutylene succinate adipate, polybutylene succinate, polycaprolactone, poly(3 It is preferable to use a biodegradable material such as -hydroxybutyrate-co-3-hydroxyhexanoate (PHBH).
• PHBH -hydroxybutyrate-co-3-hydroxyhexanoate
• thermoplastic resin fibers are softer and less stiff than pulp, so the proportion of thermoplastic resin fibers in the total papermaking fibers included in the paper base material is less than 10% by weight, and 9% by weight or less. It is preferably 5% by weight or less, more preferably 1% by weight or less, and even more preferably 1% by weight or less.
• the ratio of pulp to the total papermaking fibers contained in the paper base material is preferably 91% by weight or more, more preferably 95% by weight or more, and even more preferably 99% by weight or more.
• the thermoplastic resin fiber is not an essential material and may not be used.
• Fillers include talc, kaolin, calcined kaolin, clay, heavy calcium carbonate, light calcium carbonate, white carbon, zeolite, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, aluminum hydroxide.
• inorganic fillers such as calcium hydroxide, magnesium hydroxide, zinc hydroxide, barium sulfate, calcium sulfate, etc.
• organic fillers such as urea-formalin resin, polystyrene resin, phenolic resin, micro hollow particles, and other fillers known for paper manufacturing. can be used. Note that the filler is not an essential material and may not be used.
• auxiliary agents include rosin, alkyl ketene dimer (AKD), sizing agents such as alkenyl succinic anhydride (ASA), polyacrylamide polymers, polyvinyl alcohol polymers, cationized starches, various modified starches, urea, etc.
• ASA alkenyl succinic anhydride
• Formalin resin, dry paper strength enhancer such as melamine/formalin resin, wet paper strength enhancer, retention agent, freeness improver, coagulant, sulfuric acid, bulking agent, dye, optical brightener, pH adjuster Examples include antifoaming agents, ultraviolet inhibitors, antifading agents, pitch control agents, slime control agents, etc., and can be appropriately selected and used as required.
• the paper base material used in the present invention has a thickness of 25 ⁇ m or more and 100 ⁇ m or less.
• the thickness of the paper base material is measured in accordance with JIS P8118:2014. Since the paper base material has a thickness of 25 ⁇ m or more and 100 ⁇ m or less, it can be easily passed through a bag making machine that uses a conventional plastic film.
• the thickness of the paper base material is preferably 30 ⁇ m or more, more preferably 35 ⁇ m or more, even more preferably 40 ⁇ m or more, and preferably 90 ⁇ m or less, and 80 ⁇ m or less. More preferably, it is 70 ⁇ m or less.
• the paper base material of the present invention preferably has a basis weight of 20 g/m 2 or more and 70 g/m 2 or less from the viewpoint of flexibility and strength.
• the basis weight of the paper base material is more preferably 22 g/m 2 or more, even more preferably 24 g/m 2 or more, even more preferably 28 g/m 2 or more, and even more preferably 65 g/m 2 or more. It is more preferably 2 or less, even more preferably 60 g/m 2 or less, even more preferably 55 g/m 2 or less.
• the basis weight of the paper base material is measured in accordance with JIS P8124:2011.
• the paper base material of the present invention preferably has a density of 0.5 g/cm 3 or more and 0.95 g/cm 3 or less from the viewpoint of flexibility and strength.
• the density of the paper base material is more preferably 0.55 g/cm 3 or more, more preferably 0.9 g/cm 3 or less, even more preferably 0.85 g/cm 3 or less. , more preferably 0.75 g/cm 3 or less.
• the density of the paper base material is calculated from the thickness and basis weight.
• the paper base material of the present invention satisfies any one or more of the following conditions (1) to (4).
• the bending hysteresis 2HB in the MD direction by the KES method is 0.02 g ⁇ cm/cm or more and 1.2 g ⁇ cm/cm or less
• the bending rigidity B in the MD direction by the KES method is 0.16 g ⁇ cm 2 /cm or more and 1.8g ⁇ cm 2 /cm or less
• the other surface of the paper base material is exposed, and the smoothness of the exposed surface (Oken method) is 50 seconds or more and 700 seconds or less (4 )
• Young's modulus in the MD direction is 3 GPa or more and 15 GPa or less.
• the paper base material of the present invention preferably satisfies two or more of these conditions (1) to (4), more preferably satisfies three or more, and most preferably satisfies all four.
• the KES method is an abbreviation for Kawabata Evaluation System, and is one of the methods for measuring the physical properties of flexible materials such as nonwoven fabrics and fabrics, and can objectively evaluate tensile properties, bending properties, and shear properties.
• the bending stiffness B and bending hysteresis 2HB by the KES method can be measured, for example, using an automated pure bending tester KES-FB2-S manufactured by Kato Tech Co., Ltd.
• the bending stiffness B and the bending hysteresis 2HB which are bending characteristics, can be calculated from the relationship between the bending moment (M) and the curvature (K) during bending deformation.
• the bending stiffness B is calculated from the increase in the bending moment (M) with respect to the increase in the curvature (K), that is, the slope of the MK curve.
• the bending hysteresis 2HB represents the difference in bending moment when bending and returning, and is calculated from the difference in reciprocation of the MK curve.
• the paper base material that satisfies (1) has a bending hysteresis 2HB in the MD direction by the KES method of 0.02 g ⁇ cm/cm or more and 1.2 g ⁇ cm/cm or less.
• hysteresis 2HB The smaller the value of hysteresis 2HB, the easier it is to return to its original state after bending. If this hysteresis 2HB is less than 0.02 g cm/cm, bending, crease processing, folding, etc. will become difficult, and a force will be generated to return the bag to its original shape (flat plate shape or roll shape) after making the bag. In some cases, the soft packaging may become warped or rounded, resulting in poor cosmetic appearance and shape retention.
• this hysteresis 2HB exceeds 1.2 g/cm/cm, it will be difficult to return to the original shape after bending, so especially the parts that come into contact with the former of the bag making machine and are subjected to loads during bending and folding. may become more prone to wrinkles, and may also be more likely to tear.
• This hysteresis 2HB is preferably 0.025 g ⁇ cm/cm or more, more preferably 0.03 g ⁇ cm/cm or more, even more preferably 0.04 g ⁇ cm/cm or more, and 0.03 g ⁇ cm/cm or more.
• it is .05 g ⁇ cm/cm or more, more preferably 1.1 g ⁇ cm/cm or less, even more preferably 1.05 g ⁇ cm/cm, and even more preferably 1.0 g ⁇ cm/cm.
• it is below cm/cm, it is even more preferable that it is below 0.9 g ⁇ cm/cm, it is even more preferable that it is below 0.8 g ⁇ cm/cm, and it is even more preferable that it is below 0.7 g ⁇ cm It is even more preferable that it be less than /cm.
• paper base materials that satisfy any one or more of (2) to (4) must have a bending hysteresis 2HB in the MD direction of 0.02 g ⁇ cm/cm or more and 1.2 g ⁇ cm/cm or less according to this KES method. It is preferable that This hysteresis 2HB is more preferably 0.025 g ⁇ cm/cm or more, even more preferably 0.03 g ⁇ cm/cm or more, even more preferably 0.04 g ⁇ cm/cm or more.
• 0.05 g ⁇ cm/cm or more more preferably 1.1 g ⁇ cm/cm or less, even more preferably 1.05 g ⁇ cm/cm or less, 1 It is even more preferable that it is .0 g ⁇ cm/cm or less, even more preferably that it is 0.9 g ⁇ cm/cm or less, even more preferably that it is 0.8 g ⁇ cm/cm or less, and even more preferably that it is 0.7 g ⁇ cm/cm or less. - It is even more preferable that it is below cm/cm.
• the paper base material that satisfies (2) has a bending rigidity B in the MD direction of 0.16 g ⁇ cm 2 /cm or more and 1.8 g ⁇ cm 2 /cm or less by the KES method.
• This bending rigidity B is preferably 0.2 g ⁇ cm 2 /cm or more, more preferably 0.3 g ⁇ cm 2 /cm or more, and preferably 0.4 g ⁇ cm 2 /cm or more.
• it is 1.7 g ⁇ cm 2 /cm or less, more preferably 1.5 g ⁇ cm 2 /cm or less, and even more preferably 1.2 g ⁇ cm 2 /cm or less. It is preferably 1.0 g ⁇ cm 2 /cm or less, even more preferably 0.8 g ⁇ cm 2 /cm or less.
• paper base materials that satisfy any one or more of (1), (3), and (4) have a bending rigidity B in the MD direction of 0.16 g ⁇ cm 2 /cm or more and 1.8 g ⁇ cm by this KES method. It is preferable that it is below cm 2 /cm.
• This bending rigidity B is more preferably 0.2 g ⁇ cm 2 /cm or more, even more preferably 0.3 g ⁇ cm 2 /cm or more, and 0.4 g ⁇ cm 2 /cm or more.
• g ⁇ cm 2 /cm or less is even more preferable, more preferably 1.7 g ⁇ cm 2 /cm or less, even more preferably 1.5 g ⁇ cm 2 /cm or less, and even more preferably 1.2 g ⁇ cm 2 /cm or less. Even more preferably, it is 1.0 g ⁇ cm 2 /cm or less, even more preferably 0.8 g ⁇ cm 2 /cm or less.
• the paper base material that satisfies (3) has a smoothness (Ouken style) of the exposed surface of the paper base material of 50 seconds or more and 700 seconds or less when used as flexible packaging paper. It is.
• the flexible packaging paper of the present invention is wound into a roll, unwound from the roll, passed through a bag-making machine, conveyed while coming into contact with various members such as rollers, formers, and bag-making boards, and undergoes a creasing process. After going through a folding process, a heat-sealing process, a cutting process, etc., it becomes a soft package. At this time, if the smoothness (Oken style) of the exposed surface of the paper base material is between 50 seconds and 700 seconds, the friction and slipperiness between the paper base material and the bag making machine will be good, resulting in production failure. can be reduced.
• the smoothness of the exposed surface of the paper base material is preferably 70 seconds or more, more preferably 100 seconds or more, and preferably 650 seconds or less, and 600 seconds or more.
• the value of smoothness (Ouken type) is not specifically limited.
• the smoothness (Oken method) of the surface (back surface) on the heat seal layer side of the paper base material is It is preferable that the smoothness (the surface is rough) is smaller than the smoothness (Oken type) of , and specifically, it is preferable that the value of the smoothness (Oken type) is smaller by 30 seconds or more.
• the exposed surface (surface) of the paper base material must be It is preferable that the smoothness (Oken type) is 50 seconds or more and 700 seconds or less. This smoothness (Ouken style) is more preferably 70 seconds or more, even more preferably 100 seconds or more, more preferably 650 seconds or less, and even more preferably 600 seconds or less. The time is preferably 500 seconds or less, even more preferably 450 seconds or less.
• the value of smoothness (Ouken type) is not specifically limited.
• the smoothness (Oken method) of the surface (back surface) on the heat seal layer side of the paper base material is It is preferable that the smoothness (the surface is rough) is smaller than the smoothness (Oken type) of , and specifically, it is preferable that the value of the smoothness (Oken type) is smaller by 30 seconds or more.
• the paper base material that satisfies (4) has a Young's modulus in the MD direction of 3 GPa or more and 15 GPa or less. Young's modulus is the ratio of the force (stress) acting per unit cross-sectional area of the sample to the deformation rate (strain) when an external force is applied in a uniaxial direction within the elastic range of the object, and it is the initial slope of the stress-strain curve. It is. Young's modulus is a value representing the difficulty of deformation of a material, and the larger the Young's modulus is, the more difficult it is to deform. The Young's modulus of the paper base material in the MD direction is measured in accordance with JIS P8113:2006, Part 2 Constant Speed Stretching Method.
• the Young's modulus is less than 3 GPa, the paper base material is easily deformed, and the paper base material is stretched due to the tension during manufacturing, so it shrinks and shifts in the vertical dimension after the bag is made. , and wrinkles are more likely to occur.
• the Young's modulus exceeds 15 GPa, the tension cannot be increased during manufacturing, which tends to cause conveyance defects in which the flexible packaging paper cannot be conveyed as specified, and deviations in cutting intervals are likely to occur.
• the Young's modulus is preferably 4 GPa or more, more preferably 5 GPa or more, and also preferably 12 GPa or less, and more preferably 10 GPa or less.
• the paper base material that satisfies any one or more of (1) to (3) preferably has a Young's modulus in the MD direction of 3 GPa or more and 15 GPa or less.
• This Young's modulus is more preferably 4 GPa or more, even more preferably 5 GPa or more, more preferably 9 GPa or less, and even more preferably 8 GPa or less.
• the paper base material of the present invention preferably has a puncture strength of 1.0 N or more.
• the puncture strength of the paper base material is more preferably 1.1N or more, and even more preferably 1.2N or more.
• the puncture strength of the paper base material is measured in accordance with JIS Z1707:2019 7.5 puncture strength test.
• the base paper manufacturing (paper making) method is not particularly limited, and twin paper machines such as Fourdrinier paper machine, cylinder paper machine, short wire paper machine, gap former type, hybrid former type (on-top former type), etc.
• twin paper machines such as Fourdrinier paper machine, cylinder paper machine, short wire paper machine, gap former type, hybrid former type (on-top former type), etc.
• Known manufacturing (paper making) methods and paper machines such as a wire paper machine can be selected.
• the pH during papermaking may be any of the acidic region (acidic papermaking), pseudo-neutral region (pseudo-neutral papermaking), neutral region (neutral papermaking), and alkaline region (alkaline papermaking).
• an alkaline chemical may be applied to the surface of the paper layer.
• the base paper may have one layer or may be composed of two or more layers.
• the surface of the base paper with various chemicals.
• the agents used include oxidized starch, hydroxyethyl etherified starch, enzyme-modified starch, polyacrylamide, polyvinyl alcohol, surface sizing agents, water resistance agents, water retention agents, thickeners, lubricants, etc. These can be used alone or in combination of two or more.
• these various drugs and pigments may be used in combination. Pigments include kaolin, clay, engineered kaolin, delaminated clay, heavy calcium carbonate, light calcium carbonate, mica, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate, colloidal silica, and satin.
• Inorganic pigments such as white and organic pigments such as solid type, hollow type, or core shell type can be used alone or in combination of two or more types.
• the method of surface treatment of the base paper is not particularly limited, but known coating equipment such as a rod metering size press, pound type size press, gate roll coater, spray coater, blade coater, curtain coater, etc. can be used. .
• one or more functional layers such as a filler layer, an ink-receiving layer, a water-resistant layer, an oil-resistant layer, a water vapor barrier layer, a gas barrier layer, etc. can be formed on at least one surface of the base paper.
• the functional layer may be either a coating layer or a laminate layer, but a coating layer is preferred from the viewpoint of maintaining the flexibility of the paper base material.
• the heat-sealing layer is a layer that imparts heat-sealing properties, and specifically, it is a layer that can be bonded to an object to be bonded by applying heat and pressure. Since the flexible packaging paper of the present invention has heat sealability, it is easy to mold it into a flexible packaging material, maintain the shape after molding, and ensure sealing performance.
• the heat-sealing layer is provided on the outermost surface of at least one of the flexible packaging paper sheets.
• the heat seal layer may be either a coating layer or a laminate layer.
• the thermoplastic resin contained in the heat seal layer is not particularly limited, and may include ethylene-vinyl acetate resin, styrene-acrylic ester copolymer resin, acrylic resin, ethylene-acrylic resin, polyolefin resin (polyethylene, polypropylene, etc.) , thermoplastic resins used for heat sealing such as polyester resins (polyethylene terephthalate, polyethylene succinate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyvinyl alcohol resins, polyvinyl acetate resins, polylactic acid resins, etc.
• the heat-sealing layer can contain additives such as an anti-blocking agent and a silane coupling agent.
• the anti-blocking agent pigments, waxes, metal soaps, etc. can be used without particular limitation.
• the heat seal layer does not contain any additives.
• the dry weight of the heat seal layer is preferably 3 g/m 2 or more and 20 g/m 2 or less per side. If the dry weight is less than 3 g/m 2 , heat sealability may be reduced. Moreover, even if the dry weight exceeds 20 g/m 2 , the heat sealability is hardly improved and the cost increases.
• the heat-sealing layer may be one layer or may be composed of two or more layers. By configuring the heat-sealing layer as a multilayer of two or more layers, defects such as coating unevenness can be reduced compared to the case of a single layer.
• the heat-sealing layer is composed of two or more layers, it is preferable that the total dry weight of all the heat-sealing layers is within the above range, and the dry weight coating amount per layer is 2 g/m It is preferable that it is 2 or more.
• the thickness of the heat seal layer is preferably 20 ⁇ m or more and 100 ⁇ m or less. If the thickness is less than 20 ⁇ m, heat sealability may not be ensured. Moreover, if the thickness exceeds 100 ⁇ m, it is not preferable from the viewpoint of cost.
• the coating method is not particularly limited, and coating can be performed using a known coating device and coating system.
• the coating device include a blade coater, a bar coater, an air knife coater, a curtain coater, a spray coater, a roll coater, a reverse roll coater, a size press coater, a gate roll coater, and the like.
• the coating system may be either a water-based coating using a solvent such as water or a solvent-based coating using a solvent such as an organic solvent, but water-based coating is preferred from the viewpoint of safety and hygiene.
• the heat-sealing layer is preferably a coating layer of a water-dispersible resin or a water-soluble resin.
• the formation method thereof is not particularly limited, and for example, various methods such as extrusion lamination, wet lamination, dry lamination, etc. can be appropriately used to laminate.
• Soft packaging In the flexible packaging of the present invention, an object to be packaged is enclosed in a packaging material made of the above-mentioned flexible packaging paper of the present invention.
• the shape of the soft packaging is not particularly limited, and may be vertical pillow packaging bags, horizontal pillow packaging bags, side seal bags, two side seal bags, three side seal bags, four side seal bags, gusset bags, bottom gusset bags, stand bags, etc. be able to.
• the packaging material of the soft packaging body of the present invention is mainly paper, it is easier to tear compared to those using conventional resin packaging materials, and can be easily torn from anywhere.
• the flexible packaging paper of the present invention can be fed into packaging machines that use conventional resin films in place of resin films without changing the manufacturing conditions.
• the soft packaging of the present invention can be manufactured using conventional manufacturing machinery as is, so new equipment is not required.
• Example 1-1 As pulp raw materials, 50 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 500 ml) and 50 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 350 ml) were used. To 100 parts by weight of this mixed pulp, 0.9 parts by weight (based on pulp dry weight) of polyamine epichlorohydrin resin (WS4010, wet paper strength enhancer made by Seiko PMC) activated with caustic soda, polyacrylamide (dry weight) A paper stock containing 0.3 parts by weight of a paper strength enhancer), aluminum sulfate, and a sizing agent was prepared.
• WS4010 polyamine epichlorohydrin resin
• WS4010 wet paper strength enhancer made by Seiko PMC
• a wet paper was made from this paper stock using a paper machine, and the wet paper was dried using a Yankee dryer to obtain a paper base material (base paper).
• the smoothness (Ouken method) of the obtained paper base material was 299 seconds on the front surface and 10 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 1-2 A paper base material (base paper) was obtained using 50 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 460 ml) and 50 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 300 ml) as pulp raw materials. The rest is the same as in Example 1-1.
• the smoothness (Oken method) of the obtained paper base material was 197 seconds on the front surface and 9 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 1-3 As pulp raw materials, 80 parts by weight of bleached hardwood kraft pulp (LBKP, CSF: 500 ml) and 20 parts by weight of bleached softwood kraft pulp (NBKP, CSF 530 ml) were used. To 100 parts by weight of this mixed pulp, 0.1 part by weight of polyacrylamide (PAM) with a molecular weight of 2.5 million as a dry paper strength enhancer (based on the dry weight of the pulp) and 0.1 part by weight of alkyl ketene dimer (AKD) as a sizing agent.
• PAM polyacrylamide
• ALD alkyl ketene dimer
• a wet paper was made from this paper stock using a paper machine, and the wet paper was dried using a Yankee dryer to obtain a paper base material (base paper).
• the smoothness (Ouken method) of the obtained paper base material was 141 seconds on the front surface and 8 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 1-4 The procedure was the same as in Example 1-3, except that a paper base material (base paper) having a basis weight of about 50 g/m 2 was obtained.
• the smoothness (Ouken method) of the obtained paper base material was 83 seconds on the front surface and 10 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 1-5" Sodium polyacrylate was added as a dispersant to engineered kaolin (manufactured by Imerys, Varisurf HX, average particle size 9.0 ⁇ m, aspect ratio 80-100) (0.2% to pigment), and dispersed with a Serie mixer. A kaolin slurry with a solid content concentration of 55% was prepared. In the obtained kaolin slurry, 200 parts (solid content) of styrene-butadiene latex (manufactured by Nippon Zeon Co., Ltd., PNT7868) as a water vapor barrier resin was blended to 100 parts (solid content) of the pigment. A coating liquid for a water vapor barrier layer having a concentration of 50% was obtained. A polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA117) aqueous solution was prepared to have a solid content concentration of 10% to obtain a coating liquid for a gas barrier layer.
• engineered kaolin manufactured by Imerys, Vari
• a coating liquid for a water vapor barrier layer was coated on one side using a blade coater so that the dry weight coating amount was 12 g/m 2 and dried at 105 ° C. for 2 minutes.
• a gas barrier layer coating solution was coated on one side using a roll coater so that the coating amount was 3.0 g/m 2 in terms of dry weight, and dried at 105°C for 2 minutes to form a paper base with a functional layer. I got the material.
• the smoothness (Ouken method) of the obtained paper base material was 83 seconds on the front surface and 34 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the functional layer of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• “Comparative Example 1-1” As a pulp raw material, a mixed pulp using 60 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 40ml) and 40 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 40ml) was used as a raw material, and the pulp was made to a basis weight of 30% using a Fourdrinier paper machine. A base paper of .0 g/m 2 was made into paper, and an on-machine 2-roll size press was used to form a paper using modified PVA (RS4104 (Kuraray), content 1.0 g/m 2 ) and wet paper strength agent (WS-4020 (Starlight)).
• modified PVA RS4104 (Kuraray), content 1.0 g/m 2
• WS-4020 wet paper strength agent
• “Comparative Example 1-2" As a pulp raw material, 100 parts by weight of softwood unbleached kraft pulp (NBKP, CSF 530 ml) was used. To 100 parts by weight of this pulp, 0.1 parts by weight of polyacrylamide (PAM) with a molecular weight of 2.5 million as a dry paper strength enhancer (based on the dry weight of the pulp) and 0.35 parts by weight of alkyl ketene dimer (AKD) as a sizing agent. Paper stock containing 0.15 parts by weight of polyamide epichlorohydrin (PAEH) resin as a wet paper strength enhancer and 0.08 parts by weight of polyacrylamide (PAM) with a molecular weight of 10 million as a retention agent. prepared.
• PAM polyacrylamide
• PAEH polyamide epichlorohydrin
• Wet paper was made from this paper stock using a paper machine and dried to obtain a paper base material (base paper).
• the smoothness (Oken method) of the obtained paper base material was 15 seconds on the front surface and 12 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• the obtained paper base material or flexible packaging paper was evaluated as follows. The results are shown in Table 1.
• ⁇ B, 2HB by KES method The measurement was performed using an automated pure bending tester KES-FB2-S manufactured by Totec Co., Ltd. under the conditions of a test piece of 100 mm x 100 mm, a bending speed of 0.5 cm -1 /sec, and a maximum curvature of 2.5 cm -1 .
• the obtained soft packaging paper was cut into a width of 250 mm and wound into a roll.
• a horizontal pillow packaging machine (Omori Kikai Kogyo Co., Ltd., S-5000X BX) and a product dummy (width 75 mm x length 75 mm x height 28 mm (weight 45 g))
• the width of the bag making machine's frontage is 80 to 85 mm x height.
• 1,000 horizontal pillow bags were prepared under the conditions of a width of 35 mm, a cut pitch of 150 mm, and a rotation speed of 60 cpm, and evaluated according to the following criteria. Further, the center seal temperature was 140°C, and the top seal temperature was 110°C. In addition, production of products whose flexible packaging paper broke was discontinued at that point.
• Test 2 If (2) is satisfied "Example 2-1" As pulp raw materials, 80 parts by weight of bleached hardwood kraft pulp (LBKP, CSF: 500 ml) and 20 parts by weight of bleached softwood kraft pulp (NBKP, CSF 530 ml) were used. To 100 parts by weight of this mixed pulp, 0.1 part by weight of polyacrylamide (PAM) with a molecular weight of 2.5 million as a dry paper strength enhancer (based on the dry weight of the pulp) and 0.1 part by weight of alkyl ketene dimer (AKD) as a sizing agent.
• PAM polyacrylamide
• ALD alkyl ketene dimer
• a wet paper was made from this stock using a paper machine, the wet paper was dried using a Yankee dryer, and a supercalender treatment was performed to obtain a paper base material (base paper).
• the smoothness (Oken method) of the obtained paper base material was 610 seconds on the front surface and 103 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 2-2 As pulp raw materials, 50 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 460 ml) and 50 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 300 ml) were used. To 100 parts by weight of this mixed pulp, 0.9 parts by weight (based on pulp dry weight) of polyamine epichlorohydrin resin (WS4010, wet paper strength enhancer made by Seiko PMC) activated with caustic soda, polyacrylamide (dry weight) A paper stock containing 0.3 parts by weight of a paper strength enhancer), aluminum sulfate, and a sizing agent was prepared.
• WS4010 polyamine epichlorohydrin resin
• WS4010 wet paper strength enhancer made by Seiko PMC
• a wet paper was made from this paper stock using a paper machine, and the wet paper was dried using a Yankee dryer to obtain a paper base material (base paper).
• the smoothness (Oken method) of the obtained paper base material was 197 seconds on the front surface and 9 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 2-3 As pulp raw materials, 80 parts by weight of bleached hardwood kraft pulp (LBKP, CSF: 500 ml) and 20 parts by weight of bleached softwood kraft pulp (NBKP, CSF 530 ml) were used. To 100 parts by weight of this mixed pulp, 0.1 part by weight of polyacrylamide (PAM) with a molecular weight of 2.5 million as a dry paper strength enhancer (based on the dry weight of the pulp) and 0.1 part by weight of alkyl ketene dimer (AKD) as a sizing agent.
• PAM polyacrylamide
• ALD alkyl ketene dimer
• a wet paper was made from this paper stock using a paper machine, and the wet paper was dried using a Yankee dryer to obtain a paper base material (base paper).
• the smoothness (Ouken method) of the obtained paper base material was 141 seconds on the front surface and 8 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 2-4 The procedure was the same as in Example 2-3, except that a paper base material (base paper) having a basis weight of about 50 g/m 2 was obtained.
• the smoothness (Ouken method) of the obtained paper base material was 83 seconds on the front surface and 10 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 2-5" As pulp raw materials, 50 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 500 ml) and 50 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 350 ml) were used. To 100 parts by weight of this mixed pulp, 0.9 parts by weight (based on pulp dry weight) of polyamine epichlorohydrin resin (WS4010, wet paper strength enhancer made by Seiko PMC) activated with caustic soda, polyacrylamide (dry weight) A paper stock containing 0.3 parts by weight of a paper strength enhancer), aluminum sulfate, and a sizing agent was prepared.
• WS4010 polyamine epichlorohydrin resin
• WS4010 wet paper strength enhancer made by Seiko PMC
• a wet paper was made from this paper stock using a paper machine, and the wet paper was dried using a Yankee dryer to obtain a paper base material (base paper).
• the smoothness (Ouken method) of the obtained paper base material was 299 seconds on the front surface and 10 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 2-6 Sodium polyacrylate was added as a dispersant to engineered kaolin (manufactured by Imerys, Varisurf HX, average particle size 9.0 ⁇ m, aspect ratio 80-100) (0.2% to pigment), and dispersed with a Serie mixer. A kaolin slurry with a solid content concentration of 55% was prepared. In the obtained kaolin slurry, 200 parts (solid content) of styrene-butadiene latex (manufactured by Nippon Zeon Co., Ltd., PNT7868) as a water vapor barrier resin was blended to 100 parts (solid content) of the pigment. A coating liquid for a water vapor barrier layer having a concentration of 50% was obtained. A polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA117) aqueous solution was prepared to have a solid content concentration of 10% to obtain a coating liquid for a gas barrier layer.
• engineered kaolin manufactured by Imerys, Vari
• a coating liquid for a water vapor barrier layer was coated on one side using a blade coater so that the dry weight coating amount was 12 g/m 2 , and then dried at 105°C for 2 minutes.
• the gas barrier layer coating liquid was coated on one side using a roll coater so that the coating amount was 3.0 g/ m2 in terms of dry weight, and dried at 105°C for 2 minutes to form the paper with the functional layer.
• a base material was obtained.
• the smoothness (Ouken method) of the obtained paper base material was 83 seconds on the front surface and 34 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the functional layer of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• “Comparative Example 2-1” As a pulp raw material, a mixed pulp using 60 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 40ml) and 40 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 40ml) was used as a raw material, and the pulp was made to a basis weight of 30% using a Fourdrinier paper machine. A base paper of .0 g/m 2 was made into paper, and an on-machine 2-roll size press was used to form a paper using modified PVA (RS4104 (Kuraray), content 1.0 g/m 2 ) and wet paper strength agent (WS-4020 (Starlight)).
• modified PVA RS4104 (Kuraray), content 1.0 g/m 2
• WS-4020 wet paper strength agent
• “Comparative Example 2-2” As a pulp raw material, 100 parts by weight of softwood unbleached kraft pulp (NBKP, CSF 530 ml) was used. To 100 parts by weight of this pulp, 0.1 parts by weight of polyacrylamide (PAM) with a molecular weight of 2.5 million as a dry paper strength enhancer (based on the dry weight of the pulp) and 0.35 parts by weight of alkyl ketene dimer (AKD) as a sizing agent. Paper stock containing 0.15 parts by weight of polyamide epichlorohydrin (PAEH) resin as a wet paper strength enhancer and 0.08 parts by weight of polyacrylamide (PAM) with a molecular weight of 10 million as a retention agent. prepared.
• PAM polyacrylamide
• Wet paper was made from this paper stock using a paper machine and dried to obtain a paper base material (base paper).
• the smoothness (Oken method) of the obtained paper base material was 15 seconds on the front surface and 12 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• the obtained paper base material or flexible packaging paper was evaluated as follows. The results are shown in Table 2.
• ⁇ B, 2HB by KES method The measurement was performed using an automated pure bending tester KES-FB2-S manufactured by Totec Co., Ltd. under the conditions of a test piece of 100 mm x 100 mm, a bending speed of 0.5 cm -1 /sec, and a maximum curvature of 2.5 cm -1 .
• the obtained soft packaging paper was cut into a width of 250 mm and wound into a roll.
• a horizontal pillow packaging machine (Omori Kikai Kogyo Co., Ltd., S-5000X BX) and a product dummy (width 75 mm x length 75 mm x height 28 mm (weight 45 g))
• the width of the bag making machine's frontage is 80 to 85 mm x height.
• 1,000 horizontal pillow bags were prepared under the conditions of a width of 35 mm, a cut pitch of 150 mm, and a rotation speed of 60 cpm, and evaluated according to the following criteria. Further, the center seal temperature was 140°C, and the top seal temperature was 110°C.
• the horizontal pillow bags obtained from the flexible packaging paper obtained in Example 2-4 had opening dimensions that deviated by less than 20% from the designed design, and compared to the flexible packaging obtained in Example 2-6.
• the deviation of the opening dimensions from the design was all less than 25%, and most of them were less than 20%, but some cases were 20% or more and less than 25%. was.
• the horizontal pillow bag obtained from the flexible packaging paper obtained in Comparative Example 2-1 had no tension, and when lifted in a horizontal state, it could not resist gravity and sagged.
• the paper base material used in Comparative Example 2-1 had a small B value of 0.151 g ⁇ cm 2 /cm by the KES method and was too soft.
• the horizontal pillow bags obtained from the flexible packaging paper obtained in Comparative Example 2-2 included a plurality of bags whose horizontal dimensions deviated significantly from the designed dimensions by 25% or more. This is because the paper base material used in Comparative Example 2-2 has a large B value of 1.93 g cm 2 /cm according to the KES method, and is difficult to bend, so there is no misalignment when rolling it into a cylinder. It is presumed that this is due to the occurrence of
• Example 3-1 As pulp raw materials, 80 parts by weight of bleached hardwood kraft pulp (LBKP, CSF: 500 ml) and 20 parts by weight of bleached softwood kraft pulp (NBKP, CSF 530 ml) were used. To 100 parts by weight of this mixed pulp, 0.1 part by weight of polyacrylamide (PAM) with a molecular weight of 2.5 million as a dry paper strength enhancer (based on the dry weight of the pulp) and 0.1 part by weight of alkyl ketene dimer (AKD) as a sizing agent.
• PAM polyacrylamide
• ALD alkyl ketene dimer
• a wet paper was made from this paper stock using a paper machine, and the wet paper was dried using a Yankee dryer to obtain a paper base material (base paper).
• the smoothness (Ouken method) of the obtained paper base material was 83 seconds on the front surface and 10 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 3-2 As pulp raw materials, 50 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 460 ml) and 50 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 300 ml) were used. To 100 parts by weight of this mixed pulp, 0.9 parts by weight (based on pulp dry weight) of polyamine epichlorohydrin resin (WS4010, wet paper strength enhancer made by Seiko PMC) activated with caustic soda, polyacrylamide (dry weight) A paper stock containing 0.3 parts by weight of a paper strength enhancer), aluminum sulfate, and a sizing agent was prepared.
• WS4010 polyamine epichlorohydrin resin
• WS4010 wet paper strength enhancer made by Seiko PMC
• a wet paper was made from this paper stock using a paper machine, and the wet paper was dried using a Yankee dryer to obtain a paper base material (base paper).
• the smoothness (Oken method) of the obtained paper base material was 197 seconds on the front surface and 9 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 3-3 Wet paper was made in the same manner as in Example 3-1 to have a basis weight of about 30 g/m 2 , dried, and then supercalendered to obtain a paper base (base paper).
• the smoothness (Oken method) of the obtained paper base material was 610 seconds on the front surface and 103 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 3-4" As pulp raw materials, 50 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 500 ml) and 50 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 350 ml) were used. To 100 parts by weight of this mixed pulp, 0.9 parts by weight (based on pulp dry weight) of polyamine epichlorohydrin resin (WS4010, wet paper strength enhancer made by Seiko PMC) activated with caustic soda, polyacrylamide (dry weight) A paper stock containing 0.3 parts by weight of a paper strength enhancer), aluminum sulfate, and a sizing agent was prepared.
• WS4010 polyamine epichlorohydrin resin
• WS4010 wet paper strength enhancer made by Seiko PMC
• a wet paper was made from this paper stock using a paper machine, and the wet paper was dried using a Yankee dryer to obtain a paper base material (base paper).
• the smoothness (Ouken method) of the obtained paper base material was 299 seconds on the front surface and 10 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 3-5 Sodium polyacrylate was added as a dispersant to engineered kaolin (manufactured by Imerys, Varisurf HX, average particle size 9.0 ⁇ m, aspect ratio 80-100) (0.2% to pigment), and dispersed with a Serie mixer. A kaolin slurry with a solid content concentration of 55% was prepared. In the obtained kaolin slurry, 200 parts (solid content) of styrene-butadiene latex (manufactured by Nippon Zeon Co., Ltd., PNT7868) as a water vapor barrier resin was blended to 100 parts (solid content) of the pigment. A coating liquid for a water vapor barrier layer having a concentration of 50% was obtained. A polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA117) aqueous solution was prepared to have a solid content concentration of 10% to obtain a coating liquid for a gas barrier layer.
• engineered kaolin manufactured by Imerys, Vari
• Example 3-1 On the back side of the base paper obtained in Example 3-1, a coating solution for a water vapor barrier layer was coated on one side using a blade coater so that the dry weight coating amount was 12 g/m 2 , and dried at 105°C for 2 minutes. After that, the gas barrier layer coating liquid was coated on one side using a roll coater so that the coating amount was 3.0 g/ m2 in terms of dry weight, and dried at 105°C for 2 minutes to form the paper with the functional layer.
• a base material was obtained. The smoothness (Ouken method) of the obtained paper base material was 83 seconds on the front surface and 34 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the functional layer of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• “Comparative Example 3-1” Commercially available kraft paper (Shin Tokai Paper Co., Ltd.) was used as the paper base material. The smoothness (Oken method) of this paper base material was 14 seconds on the front surface and 4 seconds on the back surface. A heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on this paper base material by extrusion lamination to obtain a flexible packaging paper.
• “Comparative Example 3-2” As a pulp raw material, a mixed pulp using 60 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 40ml) and 40 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 40ml) was used as a raw material, and the pulp was made to a basis weight of 30% using a Fourdrinier paper machine. A base paper of .0 g/m 2 was made into paper, and an on-machine 2-roll size press was used to form a paper using modified PVA (RS4104 (Kuraray), content 1.0 g/m 2 ) and wet paper strength agent (WS-4020 (Starlight)).
• modified PVA RS4104 (Kuraray), content 1.0 g/m 2
• WS-4020 wet paper strength agent
• the obtained paper base material or flexible packaging paper was evaluated as follows. The results are shown in Table 3. ⁇ Smoothness (Ouken style) The surface of the paper base opposite to the surface on which the heat-sealing layer is provided (front surface) and the surface on which the heat-sealing layer is provided (back surface) were subjected to a digital Oken air permeability and smoothness test in accordance with JIS P8155. It was measured using a machine (manufactured by Asahi Seiko Co., Ltd.). - Puncture strength Measured from the paper base side of flexible packaging paper using an IMADA texture analyzer in accordance with JIS Z1707:2019 7.5 puncture strength test.
• the obtained soft packaging paper was cut into a width of 250 mm and wound into a roll.
• a horizontal pillow packaging machine (Omori Kikai Kogyo Co., Ltd., S-5000X BX) and a product dummy (width 75 mm x length 75 mm x height 28 mm (weight 45 g))
• the width of the bag making machine's frontage is 80 to 85 mm x height.
• 1,000 horizontal pillow bags were prepared under the conditions of a width of 35 mm, a cut pitch of 150 mm, and a rotation speed of 60 cpm, and evaluated according to the following criteria. Further, the center seal temperature was 140°C, and the top seal temperature was 110°C. In addition, production of products whose flexible packaging paper broke was discontinued at that point.
• - Breakage OK The flexible packaging paper does not break during manufacturing.
• NG The flexible packaging paper breaks during manufacturing.
• ⁇ Longitudinal dimensional stability (N 30) 1: All vertical dimensions are less than ⁇ 3% from the design. 2: All vertical dimensions are less than ⁇ 5% from the design. 3: One or more items whose vertical dimension deviated by 5% or more from the design.
• ⁇ Lateral dimensional stability (N 30) 1: All frontage dimensions are less than ⁇ 10% from the design. 2: All frontage dimensions are less than ⁇ 25% from the design. 3: There is one or more items whose frontage dimensions deviate by 25% or more from the design.
• the flexible packaging papers obtained in Examples 3-1 to 3-5 could be transported without breaking. Moreover, the obtained horizontal pillow bag had dimensions close to the designed size.
• the soft packaging paper obtained in Comparative Example 3-1 broke during bag making. This is presumed to be because the smoothness (Ouken type) was only 14 seconds and the surface was rough, so a load was applied during transportation. Furthermore, when the horizontal pillow bags manufactured before being broken were inspected, it was found that there was a large deviation from the designed dimension, especially in the vertical dimension.
• the soft packaging paper of Comparative Example 3-2 had a large misalignment at the heat-sealed portion. This is because the smoothness (Ouken type) is 1234 seconds, so the surface is smooth and has low friction, so it meandered when being transported through the bag making machine and became oblique to the flow direction. It is assumed that there is.
• Example 4-1 As pulp raw materials, 80 parts by weight of bleached hardwood kraft pulp (LBKP, CSF: 500 ml) and 20 parts by weight of bleached softwood kraft pulp (NBKP, CSF 530 ml) were used. To 100 parts by weight of this mixed pulp, 0.1 part by weight of polyacrylamide (PAM) with a molecular weight of 2.5 million as a dry paper strength enhancer (based on the dry weight of the pulp) and 0.1 part by weight of alkyl ketene dimer (AKD) as a sizing agent.
• PAM polyacrylamide
• ALD alkyl ketene dimer
• a wet paper was made from this paper stock using a paper machine, and the wet paper was dried using a Yankee dryer to obtain a paper base material (base paper).
• the smoothness (Ouken method) of the obtained paper base material was 83 seconds on the front surface and 10 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 4-2 As pulp raw materials, 50 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 460 ml) and 50 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 300 ml) were used. To 100 parts by weight of this mixed pulp, 0.9 parts by weight (based on pulp dry weight) of polyamine epichlorohydrin resin (WS4010, wet paper strength enhancer made by Seiko PMC) activated with caustic soda, polyacrylamide (dry weight) A paper stock containing 0.3 parts by weight of a paper strength enhancer), aluminum sulfate, and a sizing agent was prepared.
• WS4010 polyamine epichlorohydrin resin
• WS4010 wet paper strength enhancer made by Seiko PMC
• a wet paper was made from this paper stock using a paper machine, and the wet paper was dried using a Yankee dryer to obtain a paper base material (base paper).
• the smoothness (Oken method) of the obtained paper base material was 197 seconds on the front surface and 9 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 4-3 As a pulp raw material, a mixed pulp using 60 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 40ml) and 40 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 40ml) was used as a raw material, and the pulp was made to a basis weight of 30% using a Fourdrinier paper machine. A base paper of .0 g/m 2 was made into paper, and an on-machine 2-roll size press was used to form a paper using modified PVA (RS4104 (Kuraray), content 1.0 g/m 2 ) and wet paper strength agent (WS-4020 (Starlight)).
• NKP softwood bleached kraft pulp
• LLKP hardwood bleached kraft pulp
• Example 4-4 As pulp raw materials, 50 parts by weight of softwood bleached kraft pulp (NBKP, CSF: 500 ml) and 50 parts by weight of hardwood bleached kraft pulp (LBKP, CSF: 350 ml) were used. To 100 parts by weight of this mixed pulp, 0.9 parts by weight (based on pulp dry weight) of polyamine epichlorohydrin resin (WS4010, wet paper strength enhancer made by Seiko PMC) activated with caustic soda, polyacrylamide (dry weight) A paper stock containing 0.3 parts by weight of a paper strength enhancer), aluminum sulfate, and a sizing agent was prepared.
• WS4010 polyamine epichlorohydrin resin
• WS4010 wet paper strength enhancer made by Seiko PMC
• a wet paper was made from this paper stock using a paper machine, and the wet paper was dried using a Yankee dryer to obtain a paper base material (base paper).
• the smoothness (Ouken method) of the obtained paper base material was 299 seconds on the front surface and 10 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• Example 4-5 Sodium polyacrylate was added as a dispersant to engineered kaolin (manufactured by Imerys, Varisurf HX, average particle size 9.0 ⁇ m, aspect ratio 80-100) (0.2% to pigment), and dispersed with a Serie mixer. A kaolin slurry with a solid content concentration of 55% was prepared. In the obtained kaolin slurry, 200 parts (solid content) of styrene-butadiene latex (manufactured by Nippon Zeon Co., Ltd., PNT7868) as a water vapor barrier resin was blended to 100 parts (solid content) of the pigment. A coating liquid for a water vapor barrier layer having a concentration of 50% was obtained. A polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA117) aqueous solution was prepared to have a solid content concentration of 10% to obtain a coating liquid for a gas barrier layer.
• engineered kaolin manufactured by Imerys, Vari
• a coating liquid for a water vapor barrier layer was coated on one side using a blade coater so that the dry weight coating amount was 12 g/m 2 , and then dried at 105°C for 2 minutes.
• the gas barrier layer coating liquid was coated on one side using a roll coater so that the coating amount was 3.0 g/ m2 in terms of dry weight, and dried at 105°C for 2 minutes to form the paper with the functional layer.
• a base material was obtained.
• the smoothness (Ouken method) of the obtained paper base material was 83 seconds on the front surface and 34 seconds on the back surface.
• a heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the functional layer of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• “Comparative Example 4-1” Commercially available kraft paper (Shin Tokai Paper Co., Ltd.) was used as the paper base material. The smoothness (Oken method) of this paper base material was 14 seconds on the front surface and 4 seconds on the back surface. A heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• “Comparative Example 4-2” Commercially available glassine paper (Nippon Paper Papylia Co., Ltd.) was used as the paper base material. The smoothness (Oken method) of this paper base material was 1756 seconds for the front surface and 1424 seconds for the back surface. A heat-sealing layer made of low-density polyethylene having a thickness of 25 ⁇ m was provided on the back side of this paper base material by extrusion lamination to obtain a flexible packaging paper.
• the obtained paper base material or flexible packaging paper was evaluated as follows. The results are shown in Table 4. ⁇ Smoothness (Ouken style) The surface opposite to the surface on which the heat-sealing layer is provided (front surface) and the surface on which the heat-sealing layer is provided (back surface) of the paper base material were subjected to a digital Oken air permeability and smoothness test in accordance with JIS P8155. It was measured using a machine (manufactured by Asahi Seiko Co., Ltd.). - Puncture strength Measured from the paper base side of flexible packaging paper using an IMADA texture analyzer in accordance with JIS Z1707:2019 7.5 puncture strength test.
• the obtained soft packaging paper was cut into a width of 250 mm and wound into a roll.
• a horizontal pillow packaging machine (Omori Kikai Kogyo Co., Ltd., S-5000X BX) and a product dummy (width 75 mm x length 75 mm x height 28 mm (weight 45 g))
• the width of the bag making machine's frontage is 80 to 85 mm x height.
• 1,000 horizontal pillow bags were prepared under the conditions of a width of 35 mm, a cut pitch of 150 mm, and a rotation speed of 60 cpm, and evaluated according to the following criteria. Further, the center seal temperature was 140°C, and the top seal temperature was 110°C. In addition, production of products whose flexible packaging paper broke was discontinued at that point.
• - Breakage OK The flexible packaging paper does not break during manufacturing.
• NG The flexible packaging paper breaks during manufacturing.
• Conveyability OK The flexible packaging paper can be conveyed as specified.
• NG Misalignment occurs in the conveyance of the flexible packaging paper.
• the flexible packaging paper obtained in Examples 4-1 to 4-5 could be transported as specified without breaking.
• the obtained horizontal pillow bag also had excellent longitudinal dimensional stability.
• the flexible packaging paper obtained in Comparative Example 4-1 broke during production, so production of horizontal pillow bags was discontinued midway.
• the horizontal pillow bag manufactured before breaking was inspected, it was found that the vertical dimension was short and the bag had shrunk more than the designed dimension. This is because the Young's modulus of the paper base material is as small as 2.81 GPa, so it is assumed that the bag was transported in a stretched state in the longitudinal direction by the bag making machine and shrunk when tension was no longer applied.
• the flexible packaging paper of Comparative Example 4-2 had good longitudinal dimensional stability even though it was cut at 10 cm intervals, but it was not cut at 150 mm intervals in the longitudinal direction due to transport defects in the bag making machine. There has occurred. This is presumed to be because the Young's modulus of the paper base material is as large as 15.1 GPa, so strong tension cannot be applied, resulting in poor conveyance.

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