A biodegradable laminate for aseptic packaging

Abstract

A biodegradable laminate (1) comprising a base board (2), a tie layer (3), the tie layer (3) comprises PHA, a barrier film (4, 8, 9) is arranged on the tie layer (3). The barrier film comprises a PHA layer (4), which comprises a PHA type selected from the group consisting of PHB, PHBV, PHBH, P(3HB4HB), other co-polymers of PHB, other homopolymers such as PHO, PHH, P3HP, and combinations thereof, and a vacuum deposited layer (8, 9) which is coated on at least one side of the PHA layer. The laminate finally comprises at least one extrusion coated heat-sealable PHA layer (5, 6) which is coated on the first side of the base board and / or on the barrier film, the layer comprises a PHA type selected from the group consisting of PHB, PHBV, PHBH, P(3HB4HB), other co-polymers of PHB, other homopolymers such as PHO, PHH, P3HP, and combinations thereof.

Description

[0001] A BIODEGRADABLE LAMINATE FOR ASEPTIC PACKAGING

[0002] TECHNICAL FIELD

[0003] The present invention relates to a biodegradable laminate for aseptic packaging, said laminate comprising a base board with a first side and a second side the base board is biodegradable and comprises 0-30 wt% filler .

[0004] BACKGROUND - PROBLEM

[0005] Packaging materials for food and liquids including aseptic packages in ambient distribution, chilled distribution, or hot filled products , play an important role in the protection of the packed content . The packages should not only prolong shelf time of the packed content , but also offer a laminate or packaging structure which enables reuse and recycling .

[0006] Fibre-based materials represents a renewable source and sustainable alternative to fossil based or plastic based packaging . Fibre-based substrates such as paper or paperboard are usually extrusion or dispersion coated and / or laminated with thin polymer layers to provide barrier properties as for providing other functions such as sealing properties .

[0007] For more demanding applications , aluminium foil has been used in the laminates to provide barrier properties against particularly aroma, light , and water vapor and gases .

[0008] To offer the market more sustainable solutions , there is a need to find aluminium foil free solution, but also laminate structure which are more sustainable in terms of recycling, reuse and / or compostability .

[0009] OBJECT OF THE INVENTION

[0010] An obj ect with the invention is to provide a laminate with good barrier properties and which is recyclable and reusable .

[0011] Another obj ect is to provide a laminate for which recyclability is improved and especially pre- and postconsumer recyclability .

[0012] SUMMARY OF THE INVENTION

[0013] In accordance with the invention the biodegradable laminate is characterized in that the laminate further comprises :

[0014] - a tie layer which is arranged on the second side of the base board, the tie layer comprises a PHA type selected from the group consisting of PHB, PHBV, PHBH , P ( 3HB4HB ) , other co-polymers of PHB, other homopolymers such as PHO , PHH , P3HP, and combinations thereof ;

[0015] - a barrier film is arranged on the tie layer , the barrier film comprises :

[0016] - a PHA layer, wherein the PHA layer comprises a PHA type selected from the group consisting of PHB, PHBV, PHBH , P ( 3HB4HB ) , other co-polymers of PHB , other homopolymers such as PHO, PHH, P3HP, and combinations thereof , and

[0017] - a vacuum deposited layer which is coated on at least one side of the PHA layer , the vacuum deposited layer has a thickness of 20-500 nm, preferably 20-200 nm, the vacuum deposited layer comprises material selected from the group consisting of aluminum, magnesium, silicon, copper , aluminum oxides , magnesium oxides , silicon oxides and combinations thereof , preferably aluminum oxides ; and

[0018] - at least one extrusion coated heat-sealable PHA layer which is coated on the first side of the base board ( 2 ) and / or on the barrier film, wherein the extrusion coated layer has a coat weight of 5 -25 g / m2, the layer comprises a PHA type selected from the group consisting of PHB, PHBV, PHBH , P ( 3HB4HB ) , other co-polymers of PHB , other homopolymers such as PHO, PHH, P3HP, and combinations thereof .

[0019] DEFINITIONS

[0020] Polyhydroxyalkanoate ( PHA)

[0021] PHAs or polyhydroxyalkanoates shall in the context of the patent application refer to a biopolyester family that has a variety of structures and that are synthesized by a broad range of natural and genetically engineered bacteria and genetically engineered plant crops . PHAs can be synthesized in a wide range of environmental conditions and media by 30% of bacteria that live in soil . The bacteria produce PHAs by fermentation of sugar or lipids with the aim to store carbon and energy . Examples of bacterial strains that can produce PHAs include Alcaligenes eutrophus , Alcaligenes latus , Azotobacter , Aeromonas , Comamonas , Pseudomonads , and other genetically engineered organisms , such as genetically engineered microbes like Pseudomonas , Ralstonia and Escherichia coll . In general , PHAs are formed by enzymatic polymerization of one or more monomer units inside living bacteria or plant cell . Over 100 different types of monomers have been identified and incorporated into the PHA polymers , including 3-hydroxybutanoic acid and 3-hydroxypentanoic acid . PHAs can be classified into homopolymers , such as the well-known polyhydroxybutyrate ( PHB ) , or co-polymers like poly ( 3-hydroxybutyrate-co-3-hydroxyvalerate ) ( PHBV) . Additionally, depending on the size of the carbon chain, they are further categorized into short chain length ( SCL ) , medium chain length (MCL ) or long chain length (LCL ) PHAs . Since they constitute a broad family of biodegradable polymers , PHAs display very versatile properties that can benefit many different industrial applications , including cosmetics , biomedicine , and packaging, to name a few .

[0022] DESCRIPTION OF THE INVENTION

[0023] In the following, the invention will be described further with reference to Figures 1-2 . Note that the drawings in Figures 1-2 are schematical and not to scale .

[0024] Figure 1 shows a first embodiment of the inventive laminate .

[0025] Figure 2 shows a second embodiment of the inventive laminate .

[0026] Laminate

[0027] The inventive is a biodegradable laminate 1 suitable for aseptic packaging, liquid packaging, non-aseptic packaging, cups , lids , trays , etc .

[0028] Base board

[0029] The laminate 1 comprising a base board 2 with a first side 2a and a second side 2b . The base board 2 is biodegradable and comprises 0-30 wt% filler . The base board 2 is both biodegradable and compostable .

[0030] The base board 2 comprises delignified and / or bleached CTMP or HT-CTMP . Which CTMP or HT-CTMP has a low kappa number such as below 60 , preferably below 50 and most preferred below 40 according to ISO 302 : 2015 or TAPPI / ANSI T236 . The delignified and / or bleached CTMP or HT-CTMP ( High temperature CTMP ) can be derived from hardwood or softwood or be a mixture thereof .

[0031] The amount of the delignified and / or bleached CTMP or HT- CTMP in the board is preferably at least 20 wt% , more preferred at least 30 wt% such as 30-90 wt% based on the total fibre content . Also , the delignified or bleached CTMP or HT-CTMP is preferably used in the middle ply for creating a bulky layer .

[0032] Preferably, the base board 2 is a 3-ply paperboard comprising a first ply forming a top ply, a second ply forming a back ply and a third ply forming a middle ply .

[0033] The middle ply having a high bulk with a grammage in the range 30-250 gsm and density less than 850 kg / m3, preferably less than 750 kg / m3and most preferred less than 650 kg / m3.

[0034] At least one of the base board plies have 0-100% recycled fibres , which is defined as pre- or post-consumer waste or recycled pulp .

[0035] The recycled pulp is preferably substantially free from ink residuals , mineral oil hydrocarbons (MOSH / MOAH ) , or / and fluorescent whitening agents. The content of MOAH is less than 3 mg / kg, preferably less than 2 mg / kg and most preferred less than 0.5 mg / kg based on the BfR method of 2009 and DIN EN 16995.

[0036] The base board 2 is repulpable according to PTS RH 021 / 97 test method for Category II products standard (PTS reject <20% and preferably <15%) .

[0037] The base board 2 is recyclable according to DIN EN 13430:2004, biodegradable according to EN 13432:2000.

[0038] The base board 2 is compostable according to at least one of EN 13432:2000, ASTM D6868-21 and AS-4736-2006.

[0039] Tie layer

[0040] The laminate further comprises a tie layer 3 which is arranged on the second side 2b of the base board 2.

[0041] The tie layer 3 comprises a PHA type selected from the group consisting of PHB, PHBV, PHBH, P(3HB4HB) , other copolymers of PHB, other homopolymers such as PHO, PHH, P3HP, and combinations thereof.

[0042] Preferably, the tie layer 3 comprises a PHA type selected from the group selected consisting of PHBV with an HV molar content above 10%, PHBH with an HH molar content above 10%, P(3HB4HB) with a 4HB molar content above 10%, other co-polymers with low crystallinity, other homopolymers such as PHO, PHH, and combinations thereof.

[0043] The crystallinity of the PHA used in the tie layer 3 is 10-45% according to ASTM E794-06 (2018) . The PHA, used in the tie layer 3, has a melting point in the range of 80-140 °C, preferably 90-120 °C determined by differential scanning calorimetry according to standard ASTM D3418-21.

[0044] Barrier film

[0045] The laminate also comprises a barrier film 4, 8, 9, which is attached on the tie layer 3. The barrier film has a thickness of 10-100 pm, preferably 20-50 pm.

[0046] The barrier film comprises a PHA layer 4 with a first side 4a which faces against the tie layer 3 and a second side 4b which faces away from the tie layer 3.

[0047] The PHA layer 4 comprises a PHA type selected from the group consisting of PHB, PHBV, PHBH, P(3HB4HB) , other copolymers of PHB, other homopolymers such as PHO, PHH, P3HP, and combinations thereof.

[0048] The barrier film 4, 8, 9 further comprises at least one vacuum deposited layer 8, 9 which is coated on at least one side 4a, 4b of the PHA layer.

[0049] Figure 1 and Figure 2 discloses an embodiment where the PHA layer 4 is coated with a first vacuum deposited layer 8 on the first side 4a and a second vacuum deposited layer 9 on the second side 4b.

[0050] In a second embodiment (not shown in Figure 1 and Figure

[0051] 2) only the first side 4a of the PHA layer is coated with a vacuum deposited layer 8. In a third embodiment (not shown in Figure 1 and Figure 2) only the second side 4b of the PHA layer is coated with a vacuum deposited layer 9.

[0052] The vacuum deposited layer 8, 9 has a thickness of 20-500 nm, preferably 20-200 nm, the vacuum deposited layer comprises material selected from the group consisting of aluminum, magnesium, silicon, copper, aluminum oxides, magnesium oxides, silicon oxides and combinations thereof, preferably aluminum oxides.

[0053] Example of technologies for applying the thin vacuum deposition layer: plasma enhanced chemical vapor deposition (PECVD) , atomic layer deposition (ALD) , conventional metallization, CCVD or PECVD, or as is otherwise known in the art. In certain embodiments, the alumina and / or silica layer is deposited via CCVD or PECVD at open atmosphere. Other methods are sputtering, chemical vapor deposition (CVD) , combustion chemical vapor deposition (CCVD) , physical vapor deposition (PVD) , plasma enhanced chemical vapor deposition (PECVD) , vacuum deposition, flame deposition, and flame hydrolysis oated heat-sealable layer Moreover, the laminate comprises at least one extrusion coated heat-sealable PHA layer 5, 6 which is coated on the first side 2a of the base board 2 and / or on the barrier film 4, 8, 9. Each extrusion coated layer 5, 6 has a coat weight of 5-25 g / m2.

[0054] The layer comprises a PHA type selected from the group consisting of PHB, PHBV, PHBH, P(3HB4HB) , other co polymers of PHB , other homopolymers such as PHO , PHH, P3HP , and combinations thereof .

[0055] Optionally, at least 5 wt% of the PHA content in the extrusion coated layer 5 , 6 is recycled PHA, wherein up to 20 wt% of the PHA is pre- or post-consumer recycled PHA (mechanical or chemical recycling ) .

[0056] Figure 1 discloses a first embodiment wherein the tie layer 3 is coated directly on the second side 2b of the base board .

[0057] Pre-coating layer

[0058] Figure 2 discloses a second embodiment wherein the laminate further comprises a pre-coating layer 7 which is arranged between the second side 2b of the base board 2 and the tie layer 3 . The pre-coating layer 7 has a grammage of 1-8 gsm .

[0059] The pre-coating layer 7 can be applied single , double or triple coating .

[0060] In a first embodiment the pre-coating layer 7 is PVOH or Polysaccharide such as starch or CMC .

[0061] In a second embodiment the pre-coating layer 7 is nanocrystalline cellulose , microcrystalline cellulose or microf ibrillated cellulose .

[0062] In a third embodiment the pre-coating layer 7 is nanocrystalline cellulose , microcrystalline cellulose or microf ibrillated cellulose in combination with either PVOH or Polysaccharide . The pre-coating layer 7 prevents or at least reduces the migration of MOSH ( (Mineral Oil Saturated Hydrocarbons ) and MOAH (Mineral Oil Aromatic Hydrocarbons ) from the packaging material into food or other products .

[0063] Some advantages with the present invention :

[0064] An advantage with the innovative laminate structure is that it passes the organoleptic test according to the Robinson test DIN EN 1230-1 and DIN EN 1230-2 such that the value is below 0 . 5 .

[0065] The inventive laminate makes it easier to convert board to high barrier laminate based on non-f ossil-based polymer and compostable polymers .

[0066] The inventive laminate is easier to recycle - Plastic fraction can be degraded to raw materials for new plastic whereas fiber fraction can be easier separated and reused .

[0067] Moreover , the laminate structure facilitates sterilization, since PHA film with higher Tm can be used which allows better tolerance to sterilization .

[0068] The inventive laminate structure allows that higher content of recycled fibers can be used .

[0069] In the foregoing, the invention has been described on some specific embodiments . However, a skilled person realizes that other embodiments and variants are possible within the scope of the following claims .

Claims

C L A I M S1. A biodegradable laminate (1) for aseptic packaging, said laminate comprising a base board (2) with a first side (2a) and a second side (2b) the base board is biodegradable and comprises 0-30 wt% filler, characterized in that the laminate further comprises :- a tie layer (3) which is arranged on the second side (2b) of the base board (2) , the tie layer (3) comprises a PHA type selected from the group consisting of PHB, PHBV, PHBH, P(3HB4HB) , other co-polymers of PHB, other homopolymers such as PHO, PHH, P3HP, and combinations thereof;- a barrier film (4, 8, 9) which is arranged on the tie layer (3) , the barrier film comprises:- a PHA layer (4) , wherein the PHA layer comprises a PHA type selected from the group consisting of PHB, PHBV, PHBH, P(3HB4HB) , other co-polymers of PHB, other homopolymers such as PHO, PHH, P3HP, and combinations thereof, and- a vacuum deposited layer (8, 9) which is coated on at least one side of the PHA layer (4) , the vacuum deposited layer has a thickness of 20-500 nm, preferably 20-200 nm, the vacuum deposited layer comprises material selected from the group consisting of aluminum, magnesium, silicon, copper, aluminum oxides, magnesium oxides, silicon oxides and combinations thereof, preferably aluminum oxides; and- at least one extrusion coated heat-sealable PHA layer (5, 6) which is coated on the first side (2a) of the base board (2) and / or on the barrier film, wherein theextrusion coated layer (5, 6) has a coat weight of 5-25 g / m2, the layer comprises a PHA type selected from the group consisting of PHB, PHBV, PHBH, P(3HB4HB) , other copolymers of PHB, other homopolymers such as PHO, PHH, P3HP, and combinations thereof.

2. Laminate according to claim 1, wherein the tie layer (3) is coated directly on the second side (2b) of the base board ( 2 ) .

3. Laminate according to claim 1, wherein the laminate further comprises pre-coating layer (7) , which precoating layer is arranged between the second side (2b) of the base board (2) and the barrier film (4, 8, 9) .

4. Laminate according to claim 3, wherein the pre-coating layer (7) is PVOH or Polysaccharide such as starch or CMC.

5. Laminate according to claim 3, wherein the precoating layer (7) is nanocrystalline cellulose, microcrystalline cellulose or microf ibrillated cellulose.

6. Laminate according to claim 3, wherein the pre-coating layer (7) is nanocrystalline cellulose, microcrystalline cellulose or microf ibrillated cellulose in combination with either PVOH or Polysaccharide.

7. Laminate according to any one of claims 3-6, wherein the pre-coating layer (7) has a grammage of 1-8 gsm.

8. Laminate according to any preceding claim, wherein the crystallinity of PHA in the tie layer (3) is 10-45% according to ASTM E794-06 (2018) .

9. Laminate according to any preceding claim, wherein the PHA, used in the tie layer (3) has a melting point in the range of 80-140 °C, preferably 90-120°C determined by differential scanning calorimetry according to standard ASTM D3418-21.

10. Laminate according to any preceding claim, wherein the crystallinity of PHA in the extrusion coated heat- sealable PHA layer (5, 6) is 30-70% according to ASTM E794-06 (2018) .

11. Laminate according to any preceding claim, wherein the base board 2 is a 3-ply paperboard comprising a first ply forming a top ply, a second ply forming a back ply and a third ply forming a middle ply, which middle having a high bulk with a grammage in the range 30-250 gsm and density less than 850 kg / m3' preferably less than 750 kg / m3and most preferred less than 650 kg / m3.

12. Laminate according to any preceding claim, wherein the base board (2) is repulpable according to PTS RH 021 / 97 test method for Category II products standard (PTS reject <20% and preferably <15%) , recyclable according to DIN EN 13430:2004, biodegradable according to EN 13432:2000 and compostable according to at least one of EN 13432:2000, ASTM D6868-21 and AS-4736-2006.

13. Laminate according to claim 12, wherein the biodegradable and compostable base board comprisesdelignified or bleached CTMP which CTMP has a low kappa number such as below 60, preferably below 50 and most preferred below 40 according to ISO 302:2015 or TAPPI / ANSI T236.

14. Laminate according to any preceding claim, wherein at least one ply of the base board (2) comprises 0-100% of recycled fibres.

Images