Method of providing a package with a barrier and the package thus obtained

Abstract

A method of providing a package for pourable food products with an oxygen barrier, which method comprises the step of post-applying a liquid oxygen barrier composition comprising a polymer dispersion or solution, as a coating, onto the entire or a selected part of an outside surface of the package. The invention also relates to the package thus produced.

1 . A method of providing a package for pourable food products with an oxygen barrier, wherein it comprises the step of post-applying a liquid oxygen barrier composition comprising a polymer dispersion or solution, as a coating, onto the entire or a selected part of an outside surface of the package.  
     
     
         2 . A method according to  claim 1 , wherein said oxygen barrier composition is applied by a method in the group that consists of spraying, douching, atomising, brushing and immersion of the selected part of the package.  
     
     
         3 . A method according to  claim 1 , wherein said coating is forcibly dried or cured, preferably by a treatment in the group that consists of hot air, IR, UV and electron beam treatment or combinations thereof.  
     
     
         4 . A method according to  claim 1 , wherein said barrier composition is applied in two or more steps, preferably three or more steps, to yield two or more, preferably three or more part coating layers in the coating, and in that the part coating layers are dried and/or cured between the coating steps.  
     
     
         5 . A method according to  claim 1 , wherein said oxygen barrier composition is applied at a total coating thickness of 1-50 μm, preferably 1-40 μm, even more preferred 1-30 μm, even more preferred 1-20 μm, even more preferred 5-20 μm and most preferred 10-15 μm, measured at dry state.  
     
     
         6 . A method according to  claim 1 , wherein said package is formed mainly of a fibre based packaging laminate.  
     
     
         7 . A method according to  claim 1 , wherein said package is formed mainly of a polymeric packaging material.  
     
     
         8 . A method according to  claim 1 , wherein said selected part of the package is a part in the group that consists of a seal, an opening device, a plastic detail on the package and a plastic part of the package.  
     
     
         9 . A method according to  claim 1 , wherein said polymer dispersion or solution is based on a polymer which has functional hydroxyl groups or functional carboxylic groups.  
     
     
         10 . A method according to  claim 1 , wherein said polymer dispersion or solution is based on a polymer in the group that consists of ethylene acrylic acid copolymers, ethylene methacrylic acid copolymers, ethylene vinyl acetate copolymers, ethylene vinyl alcohol copolymer, modified ethylene copolymer, styrene copolymers and combinations thereof.  
     
     
         11 . A method according to  claim 1 , wherein said oxygen barrier composition also comprises nano-scale particles, preferably particles in the group that consists of clay particles and silica particles, and combinations thereof.  
     
     
         12 . A method according to  claim 11 , wherein said nano-scale particles are present in the oxygen barrier composition at a content of at least 20 weight %, preferably at least 30 weight % and even more preferred at least 40 weight %, but 60 weight %, more preferred 55 weight % and even more preferred 50 weight % at the most, as calculated on dry matter and the remainder essentially being said polymer.  
     
     
         13 . A method according to  claim 11 , wherein said nano-scale particles are clay particles and that said liquid barrier composition has a dry content of 2-20 weight %, preferably 3-16 weight % and even more preferred 5-12 weight %.  
     
     
         14 . A method according to  claim 11 , wherein said nano-scale clay particles have an average widest dimension of at least 0.2 μm, even more preferred 0.4 μm and most preferred 0.6 μm but 9 μm, preferably 8 μm and even more preferred 7 μm at the most, and a smallest dimension in the nano-scale range.  
     
     
         15 . A method according to  claim 11 , wherein said nano-scale clay particles are particles in the group that consists of aluminium magnesium silicate hydrate particles, preferably having an average widest dimension of at least 0.2 μm, even more preferred 0.4 μm and most preferred 0.6 μm, but 5 μm, preferably 4 μm and even more preferred 3 μm at the most and a smallest dimension in the nano-scale range, and synthetic tetrasilisic fluoromica particles, preferably having an average widest dimension of at least 4 μm, even more preferred 5 μm and most preferred 6 μm, but 9 μm, preferably 8 μm and even more preferred 7 μm at the most, and a smallest dimension in the nano-scale range.  
     
     
         16 . A method according to  claim 11 , wherein said nano-scale particles are silica particles and that said liquid barrier composition has a dry content of 15-40 weight %, preferably 20-35 weight % and even more preferred 24-31 weight %.  
     
     
         17 . A method according to  claim 11 , wherein said nano-scale silica particles are colloidal SiO 2  particles exhibiting a particle size of 3-150 nm, preferably 4-100 nm and even more preferred 5-70 nm, which particles are preferably amorphous and/or spherical.  
     
     
         18 . A method according to  claim 4 , wherein a first part coating layer is applied on the entire or selected, uncoated part of the outside surface of the package, which first part coating layer is composed of a polymer dispersion or solution that is essentially free from nanoscale particles, where after said first part coating layer is dried and/or cured and said oxygen barrier composition comprising nano-scale particles is applied as a second part coating that thereafter is dried and/or cured.  
     
     
         19 . A method according to  claim 18 , wherein a third part coating layer is applied on the entire or selected part of the outside surface of the package, that has been coated with the oxygen barrier composition second part coating, which third part coating layer is composed of a polymer dispersion or solution that is essentially free from nano-scale particles, where after said third part coating layer is dried and/or cured.  
     
     
         20 . A method according to  claim 4 , wherein said part coating layers each have a thickness of 1-20 μmm, preferably 1-10 μm, even more preferred 1-5 μm and most preferred 1-3 μm, measured at dry state.  
     
     
         21 . A method according to  claim 1 , wherein it is preceded by the steps of: 
 (a) injection moulding plastic opening devices in opening holes on a packaging material web,    (b) forming the packaging material web to a tube while sealing its longitudinal edges to each other and filling the tube with a pourable food product,    (c) intermittently sealing the tube in transversal seals and cutting the tube in the transversal seals to form cushions,    (d) folding the cushions to form dimension stabile packages, each having one plastic opening device,    where after said liquid oxygen barrier composition is applied onto the outside of said opening devices in said step (e).    
     
     
         22 . A method according to  claim 21 , wherein the packaging material web including the plastic opening devices is sterilised, preferably by a liquid sterilising agent and even more preferred by peroxide, to provide an aseptic package.  
     
     
         23 . A method according to  claim 1 , wherein it is preceded by the steps of: 
 (a) forming a blank of the packaging material into a tubular packaging capsule, while sealing its longitudinal edges to each other,    (b) moulding a top of plastics, including a device for opening of the filled package, to one end of the tubular capsule,    (c) filling the capsule with a pourable food product,    (d) folding the other end of the capsule into a bottom fold and sealing the fold, where after said liquid oxygen barrier composition is applied onto the outside of said opening devices in a step (e).    
     
     
         24 . A method according to  claim 23 , wherein the packaging material capsule and the moulded plastic top including the opening device is sterilised, preferably by a gaseous sterilising agent alone or in combination with irradiation sterilisation, more preferably by gaseous hydrogen peroxide in combination with UV irradiation.  
     
     
         25 . A package for a pourable food, having an oxygen barrier, wherein it exhibits a post-applied coating on the entire or a selected part of an outside surface of the package, which coating is composed of a dried liquid oxygen barrier composition comprising a polymer dispersion or solution.  
     
     
         26 . A package according to  claim 25 , wherein said coating is composed of two or more, preferably three or more part coating layers.  
     
     
         27 . A package according to  claim 25 , wherein said coating has a total thickness of 1-50 μm, preferably 1-40 μm, even more preferred 1-30 μm, even more preferred 1-20 μm, even more preferred 5-20 μm and most preferred 10-15 μm, measured at dry state.  
     
     
         28 . A package according to  claim 25 , wherein said package is formed mainly of a fibre based packaging laminate.  
     
     
         29 . A package according to  claim 25 , wherein said package is formed mainly of a polymeric packaging material.  
     
     
         30 . A package according to  claim 25 , wherein said package is aseptic.  
     
     
         31 . A package according to  claim 25 , wherein said selected part of the package is a part in the group that consists of a seal, an opening device, a plastic detail on the package and a plastic part of the package.  
     
     
         32 . A package according to  claim 25 , wherein said polymer dispersion or solution is based on a polymer that has functional hydroxyl groups or functional carboxylic groups.  
     
     
         33 . A package according to  claim 25 , wherein said polymer dispersion or solution is based on a polymer in the group that consists of ethylene acrylic acid copolymer, ethylene methacrylic acid copolymer, ethylene vinyl acetate copolymer, ethylene vinyl alcohol copolymer, modified ethylene copolymer, styrene copolymers and combinations thereof.  
     
     
         34 . A package according to  claim 25 , wherein said oxygen barrier composition also comprises nano-scale particles, preferably particles in the group that consists of clay particles and silica particles, and combinations thereof.  
     
     
         35 . A package according to  claim 34 , wherein said nano-scale particles are present in the oxygen barrier composition at a content of at least 20 weight %, preferably at least 30 weight % and even more preferred at least 40 weight %, but 60 weight %, more preferred 55 weight % and even more preferred 50 weight % at the most, as calculated on dry matter and the remainder essentially being said polymer.  
     
     
         36 . A package according to  claim 34 , wherein said nano-scale clay particles have an average widest dimension of at least 0.2 μm, even more preferred 0.4 μm and most preferred 0.6 μm but 9 μm, preferably 8 μm and even more preferred 7 μm at the most, and a smallest dimension in the nanoscale range.  
     
     
         37 . A package according to  claim 34 , wherein said nano-scale clay particles are particles in the group that consists of aluminium magnesium silicate hydrate particles, preferably having an average widest dimension of at least 0.2 μm, even more preferred 0.4 μm and most preferred 0.6 μm, but 5 μm, preferably 4 μm and even more preferred 3 μm at the most and a smallest dimension in the nano-scale range, and synthetic tetrasilisic fluoromica particles, preferably having an average widest dimension of at least 4 μm, even more preferred 5 μm and most preferred 6 μm, but 9 μm, preferably 8 μm and even more preferred 7 μm at the most, and a smallest dimension in the nano-scale range.  
     
     
         38 . A package according to  claim 33 , wherein said nano-scale silica particles are colloidal SiO 2  particles exhibiting a particle size of 3-150 nm, preferably 4-100 nm and even more preferred 5-70 nm, which particles are preferably amorphous and/or spherical.  
     
     
         39 . A package according to  claim 26  wherein a first part coating layer in direct contact with the entire or selected part of the outside surface of the package, which first part coating layer is composed of a dried polymer dispersion or solution that is essentially free from nanoscale particles, and in that said oxygen barrier composition coating comprising nanoscale particles constitutes a second part coating on top of the first part coating.  
     
     
         40 . A package according to  claim 39 , wherein a third part coating layer, on top of the oxygen barrier composition coating comprising nano-scale particles on the entire or selected part of the outside surface of the package, which third part coating layer is composed of a dried polymer dispersion or solution that is essentially free from nano-scale particles.  
     
     
         41 . A package according to  claim 26 , wherien said part coating layers each have a thickness of 1-20 μm, preferably 1-10 μm, even more preferred 1-5 μm and most preferred 1-3 μm, measured at dry state.