EP4435178A1 - Beschichtetes barrierepapier - Google Patents

Beschichtetes barrierepapier Download PDF

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Publication number
EP4435178A1
EP4435178A1 EP23164175.4A EP23164175A EP4435178A1 EP 4435178 A1 EP4435178 A1 EP 4435178A1 EP 23164175 A EP23164175 A EP 23164175A EP 4435178 A1 EP4435178 A1 EP 4435178A1
Authority
EP
European Patent Office
Prior art keywords
coating layer
coated paper
paper product
product
coating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP23164175.4A
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English (en)
French (fr)
Inventor
Johan A. LARSSON
Thomas GILLGREN
Wouter PROSPER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Billerud AB
Original Assignee
Billerud AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Billerud AB filed Critical Billerud AB
Priority to EP23164175.4A priority Critical patent/EP4435178A1/de
Priority to CN202480021275.5A priority patent/CN120898041A/zh
Priority to EP24715071.7A priority patent/EP4689283A1/de
Priority to PCT/EP2024/057316 priority patent/WO2024200118A1/en
Publication of EP4435178A1 publication Critical patent/EP4435178A1/de
Pending legal-status Critical Current

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Classifications

    • 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
    • D21H19/00—Coated paper; Coating material
    • D21H19/80—Paper comprising more than one coating
    • D21H19/82—Paper comprising more than one coating superposed
    • 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
    • D21H19/00—Coated paper; Coating material
    • D21H19/36—Coatings with pigments
    • D21H19/38—Coatings with pigments characterised by the pigments
    • D21H19/40—Coatings with pigments characterised by the pigments siliceous, e.g. clays
    • 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
    • D21H19/00—Coated paper; Coating material
    • D21H19/36—Coatings with pigments
    • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
    • D21H19/54—Starch
    • 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
    • D21H19/00—Coated paper; Coating material
    • D21H19/80—Paper comprising more than one coating
    • D21H19/82—Paper comprising more than one coating superposed
    • D21H19/822—Paper comprising more than one coating superposed two superposed coatings, both being pigmented
    • 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

Definitions

  • the present disclosure relates to the field of paper-based materials.
  • Flow wrapping is a horizontal-motion process in which products of any shape are wrapped in a wrapping material. It is used to pack single solid items, such as confectionery bars or multiple products already collated in trays.
  • the wrapping material has been a clear plastic film or a printed opaque plastic film.
  • the package resulting from the flow wrapping process has a longitudinal fin seal and end fin seals. The longitudinal fin seal is typically folded over so that the fin lies flat on the backside wall of the package rather than projecting from it.
  • the vertical form fill sealing (VFFS) machine is a type of automated assembly-line product packaging system. It is commonly used in the packaging industry for food and a wide variety of other products. The machine often constructs plastic bags out of a flat roll of plastic film, while simultaneously filling the bags with product and sealing the filled bags. Both solids and liquids can be bagged using this packaging system.
  • Overwrapping is the process of wrapping an item inside a protective material.
  • the item is overwrapped by the packaging material plastic and sealed, thereby making a sealed package.
  • the present disclosure aims to provide a paper-based material that can replace plastic films in packaging in for example flow wrapping processes, sealed paper bags, e-commerce bags, tissue wrapping and bedding wrappings.
  • the inventors have realized that such a paper-based material, to be commercially successful, should meet the majority, preferably all, of the following criteria:
  • a coated paper product comprising:
  • the coat weight of the first coating layer is typically at least 0.5 g/m 2 , such as 1-10 g/m 2 .
  • a preferred grammage of the first coating layer is about 0.5-3 g/m 2 due to the water content of PVOH.
  • PVOH it is also meant derivatives of PVOH including ethylated PVOH.
  • An example of PVOH is the product with the trade name "Poval” from Kuraray.
  • An example of an ethylated PVOH is the product with the trade name "Exceval” from Kuraray.
  • An ethylated PVOH typically has an ethylene content of about 5-10 % by weight, whereas a non-ethylated PVOH is typically free of ethylene groups.
  • starch-based biolatex starch particles that are dispersed in water, has a low solubility in water, and acts as a polymeric binder.
  • the size of the starch particles are approximately 100 times smaller than regular starch granules. Typical sizes is in the range of 50-200 nanometers.
  • a heat-seal layer may be provided on at least part of the second side of the paper substrate.
  • Such heat-seal layer typically comprises binder and, optionally, pigment.
  • the heat-seal layer may be provided in one or may strips to cover at least part of the second side.
  • the heat seal-layer covers the second side completely.
  • a heat-seal layer on the second side is for example advantageous if the coated paper product is to be sealed with a second paper, wherein that second paper is not heat-sealable by itself.
  • An example of such seal is a lap seal.
  • the first coating layer may comprise pigment.
  • the pigment in the first coating layer is talc and/or calcium carbonate (CaCO 3 ) and/or kaolin clay and/or mica and/or bentonite clay.
  • the first coating layer comprises talc in a binder to talc ratio between 100:5 and 100:110, such as between 100:30 and 100:110, such as between 100:30 and 100:75, or CaCO 3 in a binder to CaCO 3 ratio between 100:20 and 100:70, such as between 100:30 and 100:65 or kaolin clay in a binder to kaolin clay ratio between 100:5 and 100:110, such as between 100:30 and 100:110, such as between 100:30 and 100:75 or mica in a binder to mica ratio between 100:5 and 100:110, such as between 100:30 and 100:110, such as between 100:30 and 100:75 or bentonite clay in a binder to bentonite clay ratio between 100:5 and 100:110, such as
  • bentonite clay contains parts of montmorillonite (MMT).
  • MMT montmorillonite
  • the total pigment content is 5-70 % by dry weight of the first coating layer, such as 10-50 % by dry weight of the first coating layer.
  • the first coating layer may also be free of pigments.
  • the first coating layer comprises PVOH, starch, starch-based biolatex, SB latex or a mixture thereof as well as talc and/or CaCO 3 in the first coating layer and EAA as well as talc in the second coating layer, wherein the dry weight ratio of EAA to talc in the second coating layer is between 100:5 and 100:70.
  • the first coating layer may also be free of pigments.
  • the first coating layer preferably comprises talc in a PVOH, starch, starch-based biolatex, SB latex or a mixture thereof to talc ratio of between 100:5 and 100:110, such as between 100:30 and 100:110, such as between 100:30 and 100:75, or CaCO 3 in a PVOH, starch, starch-based biolatex, SB latex or a mixture thereof latex to CaCO 3 ratio of between 100:20 and 100:70, such as between 100:30 and 100:65.
  • a method of producing a coated paper comprising the steps of:
  • All the coating layers may be applied in-line (also referred to as on-line).
  • the productivity is increased by eliminating the handling operations linked to off-line treatment and by eliminating, or at least reducing, the amount of waste.
  • the coating weight is typically below 10 g/m 2 in the coating layers to allow for sufficient drying between coating steps as well as prior to reeling.
  • a non-blocking coating is in such case also advantageous.
  • the second coating layer is typically applied using a blade coater, rod coater, air-knife coater, rotogravure coater or curtain coater.
  • the first coating layer is typically applied using a size press, film press, blade coater, rod coater, air-knife coater, rotogravure coater or curtain coater.
  • the first and second coating layers may be applied with the same coating technique or different coating techniques.
  • the first coating layer may be produced in one single coating step or in a plurality of coating steps.
  • the first coating layer is built up by a plurality of sub-layers applied in various runs.
  • each of the sub-layers preferably have identical composition so that the formed first coating layer is homogenous.
  • At least part of the first coating layer i.e. a first sub-layer of the first coating layer, may be applied in a first coating step.
  • the rest of the first coating layer e.g., a second sub-layer, in a separate coating step and the second coating layer in yet another separate coating step.
  • a first sub-layer of the first coating layer may be applied in a first coating step, whereas a second sub-layer of the first coating layer and the second coating layer are coated in a second and same coating step.
  • the first coating layer is built up by a plurality of sub-layers
  • the first coating layer consists of the first and second sub-layers.
  • a curtain coater is preferably used to allow for application of different superposed coating compositions at the same time. Consequently, in the case of two coating steps two curtain coaters are used.
  • the first coating layer and the second coating layer may, alternatively, be applied in separate coating steps.
  • the method comprises drying between the application of the first coating layer and the application of the second coating layer. Drying is typically performed with non-contact drying, such as IR and/or hot air, or contact drying, such as a drying cylinder, or a combination of non-contact and contact drying.
  • non-contact drying such as IR and/or hot air
  • contact drying such as a drying cylinder, or a combination of non-contact and contact drying.
  • the binder of the first coating layer is PVOH, starch, starch-based biolatex, or a mixture thereof it is preferred that the binder is dispersed or dissolved in water when coating the first coating layer on the paper substrate.
  • a heat-seal layer may be coated on at least part of the second side of the paper substrate.
  • Such heat-seal layer comprises binder and, optionally, pigment.
  • the second coating layer is preferably applied on the first coating layer, i.e. directly on top of the first coating layer forming a dual superposed coating arrangement.
  • a coated paper product comprising:
  • the paper substrate is typically a machine-glazed (MG) paper or a machine finished (MF) paper.
  • the paper substrate may be calendered.
  • the MG or MF paper is typically a kraft paper, and typically at least 80%, preferably at least 90%, by dry weight of the fibres used to produce the MG or MF paper are never-dried fibres (i.e. virgin fibres).
  • An MG paper has glazed side and a non-glazed side.
  • the glazed side is the side that faced the Yankee cylinder (a polished metal cylinder sometimes referred to as a MG cylinder) used for drying the paper web in the MG papermaking machine.
  • the contact with the polished metal surface during drying makes the glazed side smoother than the non-glazed side.
  • the first coating layer is applied to the less smooth, non-glazed, side of the paper substrate, i.e. the first side of the paper substrate.
  • the second coating layer is applied. It is beneficial to apply the coating on the non-glazed side to provide the glazed side for printing.
  • the glazed side may be coated with a thin layer of starch ( ⁇ 1 g/m 2 ) for curl prevention.
  • the Bendtsen roughness according to ISO 8791-2:2013 of the glazed side of the paper substrate is typically below 90 ml/min, preferably 70 ml/min or lower, more preferably below 55 ml/min.
  • the PPS roughness according to ISO 8791-4:2007 of the glazed side of the coated paper product is typically below 6.00 ⁇ m, such as below 5.00 ⁇ m, such as below 4.00 ⁇ m.
  • An MF paper is produced by a drying technique using a large number of smaller, steam-heated cylinders to dry the paper which is alternately wrapped one way and then the other way so that both sides of the paper receive the same finish.
  • the finish on both sides of an MF paper is similar to the non-glazed side of an MG paper.
  • the second side is typically a print side.
  • a lacquer may be provided on the optional print, e.g. to modify gloss, friction and/or release properties.
  • the heat-seal coating layer on at least part of the second side typically comprises binder and, optionally, pigment.
  • the grammage measured according to ISO 536:2020 of the paper substrate is typically 40-135 g/m 2 , 40-100 g/m 2 , such as 40-90 g/m 2 , such as 40-60 g/m 2 , such as 42-55 g/m 2 .
  • a suitable density (measured according to ISO 534:2011) for the paper substrate is 750-950 kg/m 3 .
  • a too low density is disadvantageous since such paper is too porous for application of a thin barrier.
  • the thickness measured according to ISO 534:2011 of the coated paper product is 50-156 ⁇ m, such as 55-126 ⁇ m, such as 55-70 ⁇ m, such as 57-67 ⁇ m.
  • a suitable thickness (measured according to ISO 534:2011) of the paper substrate is 50-80 ⁇ m, such as 50-64 ⁇ m, such as 52-61 ⁇ m.
  • a too high grammage or thickness makes the paper not suitable for a flow wrapping process as the paper should be flexible.
  • the paper substrate may be bleached, e.g. has an ISO Brightness according to ISO 2470 of at least 77 or unbleached, e.g. has an ISO Brightness according to ISO 2470 of below 60.
  • the coatings may comprise a rheology modifier to facilitate the coating operation.
  • the first coating layer typically comprises pigment and the pigment is preferably talc and/or calcium carbonate (CaCO 3 ) and/or clay and/or mica and/or bentonite clay.
  • the first coating comprises talc in a EAA or VAcA or SA or acrylic latex to talc ratio between 100:5 and 100:110, such as between 100:30 and 100:110, such as between 100:30 and 100:75 or CaCO 3 in a EAA or VAcA or SA or acrylic latex to CaCO 3 ratio between 100:20 and 100:70, such as between 100:30 and 100:65 or EAA or VAcA or SA or acrylic latex to kaolin clay in a ratio between 100:5 and 100:110, such as between 100:30 and 100:110, such as between 100:30 and 100:75 or EAA or VAcA or SA or acrylic latex to mica in a ratio between 100:5 and 100:110, such as between 100:30 and 100:110, such as between 100:30 and 100:75 or EAA or VA
  • the dry weight ratio of EAA to talc in the second coating layer is preferably between 100:10 and 100:70, such as between 100:10 and 100:60, such as between 100:15 and 100:60, such as between 100:15 and 100:40. It is advantageous with such filler to EAA or VAcA or SA or acrylic latex ratios in the first and second coating layers with respect to coating ductility, blocking, barrier properties and heat-sealability.
  • at least 50% by weight of the total pigment content in the second coating layer is talc.
  • the total pigment content of the second coating layer is 4-70 % by dry weight, such as 5-50 % by dry weight of the third coating layer.
  • the coated paper product is typically heat-sealable.
  • EAA is inherently heat-sealable and by addition of a dry weight ratio of EAA to talc in the second coating layer of between 100:5 and 100:70, this heat-sealability is typically maintained.
  • a higher talc content impairs the sealability as well as the barrier crack resistance.
  • the maximum heat seal strength measured according to ASTM F88 & EN 868-5 of the coated paper product is at least 2.8 N measured on a 15 mm test strip sealed for 0.5 s at 160 °C and 3 bar. This means that 2.8 N is required to separate the sealed strip. It is advantageous for the coated paper product to be heat-sealable in order to allow the formation of a flow-wrap packaging by sealing the paper to itself.
  • the second coating layer typically forms a surface to which a sealant layer can be applied, typically a cold-sealant layer.
  • the contact angle between water and the second coating layer surface is preferably less than 95°, such as less than 90°, such as less than 80°.
  • the contact angle may be measured according to TAPPI T 558. This standard stipulates measuring the contact angle at different checkpoints.
  • the contact angle at the 1.0 s checkpoint is selected.
  • the contact angle between di-iodomethane (DIM) and the second coating layer surface is preferably less than 60° and the surface energy is at least 30 mJ/m 2 at the 1.0 s checkpoint measured according to TAPPI T 558.
  • the surface energy is derived from the contact angle measurements by plotting (1+cos ⁇ )/2 ⁇ ( ⁇ L / ⁇ L d ) 1/2 ) vs ( ⁇ L p / ⁇ L d ) 1/2 , wherein ⁇ is the contact angle formed between the liquid drop and solid surface, ⁇ L is the liquid surface tension, and superscripts d and p stand respectively for dispersive and polar components of the liquid surface tension.
  • ⁇ is the contact angle formed between the liquid drop and solid surface
  • ⁇ L is the liquid surface tension
  • superscripts d and p stand respectively for dispersive and polar components of the liquid surface tension.
  • the points are fitted to a straight line to calculate ⁇ s p and ⁇ s d from the slope and intersection with the vertical axis, respectively.
  • ⁇ s is the solid surface free energy and the surface energy is the sum of ⁇ s p + ⁇ s d .
  • the second coating layer typically can either be heat-sealed without the need for an additional sealant layer or coated by and sealed by an additional sealant layer, typically a cold seal layer.
  • a sealant layer typically a cold-seal layer, is arranged on at least part of the second coating layer.
  • the coat weight of the first coating layer is typically 4-10 g/m 2 .
  • the coat weight of the second coating layer is typically 3-9 g/m 2 .
  • the first and/or second coating layer may comprise clay, such as kaolin clay.
  • the clay is preferably a platy clay, preferably having a form factor of at least 20, such as at least 30, such as at least 40.
  • the repulpability measured according to PTS Method PTS-RH 021/97 of the coated paper product is typically at least 80%. There are four sublevels of repulpability (level A+, A, B, C). A repulpability of at least 80 % is classified as level A repulpable.
  • HVTR hexane/heptane vapor transmission rate
  • the water vapor transmission rate (WVTR) measured according to ISO 15106-1 at 23°C and 50% relative humidity (RH) of the coated paper product is typically below 30 g/(m 2 day). Further WVTR measured according to ISO 15106-1 at 30°C and 80% relative humidity (RH) of the coated paper product is typically below 105 g/(m 2 day).
  • Average show through time of palm kernel oil measured according to Standard ISO 16532-1 of the coated paper product is typically at least 45 minutes. Further minimum show through time of palm kernel oil measured according to Standard ISO 16532-1 of the coated paper product is typically at least 10 minutes.
  • a resistance to palm kernel oil is a measure of grease resistance.
  • the ash content is below 10 % calculated according:
  • the dry weight ratio of EAA to talc in the second coating layer is preferably between 100:10 and 100:70, such as between 100:10 and 100:60, such as between 100:15 and 100:60, such as between 100:15 and 100:40. It is advantageous with such ratios in the first and second coating layers with respect to coating ductility, blocking, barrier properties and heat-sealability.
  • the coated paper product is typically heat-sealable.
  • EAA is inherently heat-sealable and by addition of a dry weight ratio of EAA to talc in the second coating layer of between 100:5 and 100:70, this heat-sealability is typically maintained.
  • a higher talc content impairs the sealability as well as the barrier crack resistance.
  • the maximum heat seal strength measured according to ASTM F88 & EN 868-5 of the coated paper product is at least 2.8 N measured on a 15 mm test strip sealed for 0.5 s at 160 °C and 3 bar. This means that 2.8 N is required to separate the sealed strip. It is advantageous for the coated paper product to be heat-sealable in order to allow the formation of a flow-wrap packaging by sealing the paper to itself.
  • the second coating layer typically forms a surface to which a sealant layer can be applied, typically a cold-sealant layer.
  • the contact angle between water and the second coating layer surface is preferably less than 95°, such as less than 90°, such as less than 80°.
  • the contact angle may be measured according to TAPPI T 558. This standard stipulates measuring the contact angle at different checkpoints.
  • the contact angle at the 1.0 s checkpoint is selected.
  • the contact angle between di-iodomethane (DIM) and the second coating layer surface is preferably less than 60° and the surface energy is at least 30 mJ/m 2 at the 1.0 s checkpoint measured according to TAPPI T 558.
  • the surface energy is derived from the contact angle measurements by plotting (1+cos ⁇ )/2 ⁇ ( ⁇ L / ⁇ L d ) 1/2 ) vs ( ⁇ L p / ⁇ L d ) 1/2 , wherein ⁇ is the contact angle formed between the liquid drop and solid surface, ⁇ L is the liquid surface tension, and superscripts d and p stand respectively for dispersive and polar components of the liquid surface tension.
  • ⁇ is the contact angle formed between the liquid drop and solid surface
  • ⁇ L is the liquid surface tension
  • superscripts d and p stand respectively for dispersive and polar components of the liquid surface tension.
  • the points are fitted to a straight line to calculate ⁇ s p and ⁇ s d from the slope and intersection with the vertical axis, respectively.
  • ⁇ s is the solid surface free energy and the surface energy is the sum of ⁇ s p + ⁇ s d .
  • the second coating layer typically can either be heat-sealed without the need for an additional sealant layer or coated by and sealed by an additional sealant layer, typically a cold seal layer.
  • a heat seal layer on at least part of the second side of the paper substrate may also be provided.
  • the first coating layer comprises EAA to talc in a ratio of between 100:30 and 100:75 and the second coating layer comprises EAA to talc in a ratio of 100:15 to 100:40.
  • Such embodiment is advantageous as it combines barrier properties, barrier crack resistance, blocking resistance, grease resistance, heat sealability and possible application of a sealant layer.
  • the first coating layer comprises VAcA to pigment in a ratio of between 100:30 and 100:75 and the second coating layer comprises EAA to talc in a ratio of 100:15 to 100:40.
  • VAcA to pigment
  • EAA to talc in a ratio of 100:15 to 100:40.
  • Such embodiment is beneficial in terms of combining barrier crack resistance, blocking resistance, grease resistance, repulpability, low ash content and possible application of a sealant layer.
  • the first coating layer comprises acrylic latex to pigment in a ratio between 100:30 and 100:110 and the second coating layer comprises EAA to talc in a ratio between 100:50 and 100:70.
  • Such embodiment is beneficial in terms of combining mineral oil barrier properties as well as water vapour barrier properties with barrier crack resistance, blocking resistance, grease resistance, repulpability and possible application of a sealant layer.
  • a flow-wrapped product obtained by flow-wrapping a product in a coated paper product according to the first aspect or in a coated paper product according to the third aspect, wherein the flow-wrapped product has a longitudinal fin seal and end fin seals.
  • a flow-wrapped product is obtainable from a HFFS machine.
  • a sealed bag such as a gusseted bag or a pillow bag, having a longitudinal seal and each end portion is sealed by a fin seal produced from a coated paper product according to the first aspect or from a coated paper product according to the third aspect.
  • a filled gusseted bag is obtainable from a VFFS machine.
  • Such bag has a longitudinal seal adhering two overlapping ends of the paper material to each other to form a lap seal.
  • the longitudinal seal is a fin seal.
  • the bag has a top end sealed by a fin seal and a bottom end sealed by a fin seal.
  • a filled pillow bag is obtainable from a VFFS machine.
  • Such bag has a longitudinal seal adhering two overlapping ends of the paper material to each other to form a lap seal.
  • the longitudinal seal is a fin seal.
  • the bag has a top end sealed by a fin seal and a bottom end sealed by a fin seal.
  • a coated paper product according to the first aspect or a coated paper product according to the third aspect for wrapping a product, such as flow-wrapping a product, in sealable paper bags, such as a gusseted bag or a pillow bag, in e-commerce packaging, in bedding packaging, such as pillow packaging, or in tissue wrapping.
  • a seventh aspect of the present disclosure there is provided a method of producing a coated paper comprising the steps of:
  • a method of flow-wrapping a product comprising a step of flow-wrapping the product in a coated paper product according to the first aspect of the present disclosure or a coated paper product according to the third aspect of the present disclosure, wherein said flow-wrapping step comprises formation of a fin seal by sealing the coated paper product.
  • the sealing is conducted by heat-sealing.
  • the method further comprises the step of applying a sealant layer, preferably a cold-seal layer, onto part of the third coating layer prior to formation of a fin seal and sealing is conducted by sealing said sealant layer.
  • the base paper is typically an MG paper.
  • the method may further comprise the step of printing the glazed side of the coated paper product.
  • the printing of the glazed side of the coated paper product and the printing and the application of the sealant layer may be carried out in the same machine.
  • the coated paper product is formed into a bag, filled and sealed in a machine, such as a form fill sealing (FFS) machine, such as a vertical form fill sealing (VFFS) machine or horizontal form fill sealing (HFFS) machine.
  • FFS form fill sealing
  • VFFS vertical form fill sealing
  • HFFS horizontal form fill sealing
  • a typical product to be flow-wrapped in the paper-based material of the present disclosure is a protein bar, a snack bar or a chocolate bar.
  • a method of forming a filled bag in which a coated paper product according to the first aspect of the present disclosure or a coated paper product according to the third aspect of the present disclosure is formed into a bag, filled and sealed in a machine, such as a form fill sealing (FFS) machine, such as a vertical form fill sealing (VFFS) machine or horizontal form fill sealing (HFFS) machine.
  • a machine such as a form fill sealing (FFS) machine, such as a vertical form fill sealing (VFFS) machine or horizontal form fill sealing (HFFS) machine.
  • FFS form fill sealing
  • VFFS vertical form fill sealing
  • HFFS horizontal form fill sealing
  • a typical product to be packed in a sealed barrier bag made from the paper-based material of the present disclosure are dry foods, such as confectionary or baked goods.
  • the product is cosmetics and toiletries.
  • the paper product may be sealed to itself in step c).
  • the wrapped item can be produced from a single paper product by folding the paper product followed by heat-sealing.
  • the paper product is sealed to a second paper product in step c).
  • the overwrapped item can be produced without the need for folding any of the paper products.
  • a typical item, i.e. product, that is wrapped is tissue wrapping, such as wrapping of rolls of kitchen paper towels and/or toilet paper, or bedding wrappings, such as pillows and duvets.
  • Pigment (talc (Finntalc C15B2), kaolin clay (Barrisurf LX), CaCO 3 (Setacarb HG-ME 75%)) was added to and dispersed in an ethylene acrylic acid (EAA) latex (Michem Flex HS 1130) having a solids content of about 45% or vinyl acetate acrylate copolymer (VAcA) latex (CHP 125) having a solids content of about 50% or acrylic latex (Rhobarr 214, DOW) having a solids content of about 45%.
  • EAA ethylene acrylic acid
  • VAcA vinyl acetate acrylate copolymer
  • CHP 125 vinyl acetate acrylate copolymer
  • acrylic latex Rabarr 214, DOW
  • a machine-glazed (MG) base paper produced from never-dried bleached SW pulp was coated on the non-glazed side with a pilot-scale blade coater for samples 1-17 & 20-23.
  • the properties of the MG base paper is shown in Table 1 below.
  • Table 1 Properties of a MG kraft paper produced from never-dried bleached SW pulp.
  • Property Unit Standard method Value Grammage g/m 2 ISO 536 48.15 Thickness ⁇ m ISO 534 56.80 Density kg/m 3 ISO 534 847.71
  • sample 18-19 Two samples (sample 18-19) were produced by coating a machine finished (MF) base paper with a grammage of 70 g/m 2 (sample 18) and a grammage of 80 g/m 2 (sample 19) in the same way as on the MG base paper.
  • MF machine finished
  • a first coating layer comprising latex and pigment (samples 1-16 & 18-22) or latex but no pigment (sample 17) was coated onto the paper.
  • the coated paper was dried by IR and a drying cylinder.
  • a second coating layer comprising latex and pigment (samples 1-18 & 22-23) or latex but no pigment (samples 20-21) was coated so that the paper was coated on one side with a dual superposed coating.
  • the coating was dried by IR, hot air and a drying cylinder.
  • Table 2 The composition of each coating is presented in Table 2.
  • WVTR water vapour transmission rate
  • HVTR hexane/heptane vapour transmission rate
  • the inventors have realized that the greatest contribution to the barrier properties is provided by the composition of the second barrier coating. It is, thus, fair to assume that other binders in the first coating layer than the ones evaluated herein will provide good barrier properties as long as the second coating layer is according to the present disclosure.
  • the ductility is measured, i.e. how well the formed barrier resists cracking. The methods is described in detail herein.
  • Rape seed oil was mixed with 1 % colorant (Sudan blue II) and stirred on a magnetic stirrer until fully mixed.
  • 3 samples (14 ⁇ 14 cm) of each coated paper were prepared.
  • the samples were one by one arranged in a folding punch with the barrier side downwards.
  • the folding punch has a V-shaped punch and a V-shaped weight is arranged on top so that when the sample is pushed down by the weight, a 90° fold-line along the entire paper is formed.
  • the weight was applied on the opposite side of the paper from the barrier coating pushing the barrier side downwards.
  • Two additional fold-lines were formed on the paper. All three fold-lines were evenly distributed with a distance of about 4 cm. After the third fold-line had been formed, the paper was turned 90° and three additional fold-lines were made in the same way, thereby obtaining a grid pattern.
  • a blotting paper was arranged with one paper sample on top of the blotting paper.
  • the paper sample had the barrier coated side upwards.
  • the coloured rape seed oil (10 ml) was dosed into the ring and evenly distributed over the paper sample immediately. After 2 minutes the paper sample was taken out from the ring and excess oil was removed with additional blotting papers and lint-free drying paper.
  • a high barrier crack resistance in combination with blocking resistance as well as good barrier properties against both water vapour and mineral oil was obtained for both pigmented pre-coating (samples 11-16,18-19 & 23) as well as a pre-coating free of pigments (sample 17).
  • DIM contact angle was measured according to TAPPI T 558 on the surface of the second coating layer to evaluate the wetting of the surface.
  • the surface energy is derived from the contact angle measurements by plotting (1+cos ⁇ )/2 ⁇ ( ⁇ L / ⁇ L d ) 1/2 ) vs ( ⁇ L p / ⁇ L d ) 1/2 , wherein ⁇ is the contact angle formed between the liquid drop and solid surface, ⁇ L is the liquid surface tension, and superscripts d and p stand respectively for dispersive and polar components of the liquid surface tension.
  • the points were fitted to a straight line to calculate ⁇ s p and ⁇ s d from the slope and intersection with the vertical axis, respectively.
  • ⁇ s is the solid surface free energy and the surface energy is the sum of ⁇ s p + ⁇ s d .
  • the contact angle as well as surface energy reflects the ability of the surface to be coated, i.e. wetted, with a sealant layer.
  • the measurement was conducted at the 1.0 s checkpoint. The results are presented in Table 7.
  • a cold-seal (Loctite Liofol CS 22-422, Henkel) was applied onto the second coating by using a lab rod coater. If a uniform coating was formed, i.e. did coating did not form pearls, the surface could be wet by the cold-seal.
  • the total surface energy is the key factor to wetting. Moreover, it is believed by the inventors that it is the top-coating that contributes the most to the total surface energy. A similar top-coat to that in samples 9-11 is therefore fair to assume that such top-coat is also wettable with a cold-seal. Table 7. Water contact angle, Di-iodomethane (DIM) contact angle and surface energy.
  • DIIM Di-iodomethane
  • the show through times of palm kernel oil is a measure of grease resistance and was measured according to Standard ISO 16532-1. Minimum time as well as average time are presented in Table 8. Table 8. Show through time of palm kernel oil. Sample Average show through (min) Minimum show through (min) 1 313 190 2 130 80 3 243 120 4 213 120 5 165 113 6 189 109 7 103 103 8 70 53 9 193 115 10 160 148 11 90 54 12 537 43 13 48 36 14 576 335 15 60 10 16 182 34 17 18 1044 281 19 603 20 21 22 49 37 23 379 93
  • the ash content was calculated according: (3% ash in 48 g/m 2 base paper + X1 % pigment in Y1 g/m 2 in first coating layer + X2 % pigment in Y2 g/m 2 second coating layer) / Z g/m 2 ; wherein

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  • Dispersion Chemistry (AREA)
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EP23164175.4A 2023-03-24 2023-03-24 Beschichtetes barrierepapier Pending EP4435178A1 (de)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP23164175.4A EP4435178A1 (de) 2023-03-24 2023-03-24 Beschichtetes barrierepapier
CN202480021275.5A CN120898041A (zh) 2023-03-24 2024-03-19 涂布阻隔纸
EP24715071.7A EP4689283A1 (de) 2023-03-24 2024-03-19 Beschichtetes barrierepapier
PCT/EP2024/057316 WO2024200118A1 (en) 2023-03-24 2024-03-19 Coated barrier paper

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EP23164175.4A EP4435178A1 (de) 2023-03-24 2023-03-24 Beschichtetes barrierepapier

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019099787A1 (en) * 2017-11-17 2019-05-23 Imerys Usa, Inc. Heat-seal coatings
JP6939976B1 (ja) * 2020-05-27 2021-09-22 王子ホールディングス株式会社 ヒートシール紙、包装袋
EP3929355A1 (de) * 2020-06-23 2021-12-29 Sustainable Carbohydrate Innovation Co., Ltd. Papiermaterial und flexibles verpackungsmaterial mit verwendung davon
JP2022011700A (ja) * 2020-06-30 2022-01-17 王子ホールディングス株式会社 ヒートシール紙
JP2023010964A (ja) * 2020-07-28 2023-01-20 日本製紙株式会社 ヒートシール紙
JP2023027649A (ja) * 2021-08-17 2023-03-02 王子ホールディングス株式会社 バリア性積層体

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB201408675D0 (en) * 2014-05-15 2014-07-02 Imerys Minerals Ltd Coating composition

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019099787A1 (en) * 2017-11-17 2019-05-23 Imerys Usa, Inc. Heat-seal coatings
JP6939976B1 (ja) * 2020-05-27 2021-09-22 王子ホールディングス株式会社 ヒートシール紙、包装袋
EP3929355A1 (de) * 2020-06-23 2021-12-29 Sustainable Carbohydrate Innovation Co., Ltd. Papiermaterial und flexibles verpackungsmaterial mit verwendung davon
JP2022011700A (ja) * 2020-06-30 2022-01-17 王子ホールディングス株式会社 ヒートシール紙
JP2023010964A (ja) * 2020-07-28 2023-01-20 日本製紙株式会社 ヒートシール紙
JP2023027649A (ja) * 2021-08-17 2023-03-02 王子ホールディングス株式会社 バリア性積層体

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