Recyclable sheet material and a container thereof

Abstract

The present invention relates to a recyclable sheet material and a container formed of such recyclable sheet material. The recyclable sheet material comprises a paper board coated on at least one uncoated surface with at least one of a water barrier coating and a first surface coating. The water barrier coating provides a surface with a smoothness equal to or less than 500 ml/min. The first surface coating may comprise at least one mineral pigment and at least one polymeric binder and may provide a surface with a smoothness that is 100 ml/min or less. The first surface coating may further be coated with a water barrier coating.

1 . A recyclable sheet material comprising:
 a paper board having a grammage of 170-300 g/m 2 , said paper board being coated on at least one uncoated surface with at least one of:   1a) a water barrier coating to provide said at least one surface with a smoothness equal to or less than 500_ml/min according to Bendtsen, ISO 8791-2 and   1b) a first surface coating based on 70-90 dried wt % of at least one mineral pigment and on 10-30 dried wt % of at least one polymeric binder, wherein said first surface coating has a smoothness of 100_ml/min or less according to Bendtsen, ISO 8791-2, is coated with a water barrier coating,   wherein said water barrier coating is based on at least one polymer component having a melting point of at least 120_° C. and is applied in an amount up to 10 g/m 2  at maximum providing a COBB value of the water barrier coated paper board 1a) and coated paper board 1b) equal to or less than 8 g/m 2  per 600 sec and a surface energy equal to or greater than 38 mJ/m 2  at 20_° C. (test liquid:water), and   wherein an amount of non-cellulosic material is at most 15 wt % of the sheet material.   
     
     
         2 . A recyclable sheet material according to  claim 1  further comprising a sealable coating covering at least partially in designated areas of each of said water barrier coating, wherein said sealable coating is based on at least one polymer having a melting point of at least 10_° C. below the melting point of the polymer component of the water barrier coating. 
     
     
         3 . A recyclable sheet material according to  claim 1 , wherein the water barrier coating amounts up to 10 g/m 2  at maximum, which amount decreases with increasing smoothness of the paper board surface coated with the water barrier coating at a given COBB value. 
     
     
         4 . A recyclable sheet material according to  claim 1 , wherein the first surface coating of the paper board 1b) is based on at least a mineral pigment selected from the group consisting of clay, talc, calcium carbonate, titanium dioxide, kaolin and mixtures thereof, and a polymeric binder. 
     
     
         5 . A recyclable sheet material according to  claim 1 , wherein the polymeric binder of the first surface coating of the paper board 1b) is based on at least one polymer selected from the group consisting of polyacrylates, acrylate copolymers, acrylate/styrene copolymers, polyvinyl acetates, ethylene/vinyl acetate copolymers, styrene copolymers, styrene/butadiene copolymers, styrene/butylacrylate copolymers, and mixtures thereof. 
     
     
         6 . A recyclable sheet material according to  claim 1 , wherein the first surface coating of the paper board 1b) is based on a dried water-based dispersion comprising 75-85 dried wt % of at least one mineral pigment and 15-25 dried wt % of at least one polymeric binder. 
     
     
         7 . A recyclable sheet material according to  claim 1 , wherein the water barrier coating is based on at least one polymer selected from the group consisting of acrylate polymers, acrylate copolymers, methacrylate polymers, methacrylate copolymers, styrene copolymers, styrene/butylacrylate copolymers, ethylene/vinyl acetate copolymers and mixtures thereof, said water barrier coating having a surface energy equal to or greater than 38 mJ/m 2  at 20_° C. (test liquid:water). 
     
     
         8 . A recyclable sheet material according to  claim 1 , wherein the water barrier coating is based on 95-99 dried wt % of the polymer component and 1_-5 dried wt % of auxiliary agents, based on the total weight of the water barrier coating when said water barrier coating is dried. 
     
     
         9 . A recyclable sheet material according to  claim 1 , wherein the water barrier coating provides a COBB value of 1-5 g/m 2  per 600 seconds of the coated paper board 1a), and coated paper board 1b). 
     
     
         10 . A recyclable sheet material according to  claim 2 , wherein the sealable coating is based on at least one polymer selected from the group consisting of acrylate polymers, acrylate copolymers, methacrylate polymers, methacrylate copolymers, styrene copolymers, styrene/acrylate copolymers, ethylene/vinyl acetate copolymers and mixtures thereof. 
     
     
         11 . A recyclable sheet material according to  claim 2 , wherein said sealable coating is coated on the water barrier coating in an amount of 12 g/m 2  at maximum at the designated areas of the water barrier coating. 
     
     
         12 . A recyclable sheet material according to  claim 2 , wherein the sealable coating is based on 95-99 dried wt % of the polymer component and 1-5 dried wt % of auxiliary agents. 
     
     
         13 . A recyclable sheet material according to  claim 1 , wherein the polymer component of the water barrier coating and the sealable coating each have a glass transition temperature T g  of 10_° C.-30_° C. (measured according to DSC). 
     
     
         14 . A recyclable sheet material according to  claim 1 , wherein the water barrier coating also functions as a sealable coating having a melting point equal to or less than 150° C. 
     
     
         15 . A recyclable sheet material according to  claim 1 , wherein a second surface of the paper board is provided with the same sequence of coatings as a first surface of the paper board 1a), and paper board 1b). 
     
     
         16 . A recyclable sheet material according to  claim 1 , wherein the recyclable sheet material is formed as a container, and wherein the water barrier coated surface is arranged as an inwardly directed surface of the container. 
     
     
         17 . A recyclable sheet material according to  claim 16 , wherein the container is adapted for containing at least one of a hot beverage, a cold beverage, ice cream, a hot liquid, a cold liquid, a hot food and a cold food. 
     
     
         18 . A recyclable sheet material according to  claim 16 , wherein the container is adapted for single use.