A SHEET-LIKE COMPOSITE, ESPECIALLY FOR CONTAINERS, WITH AN ADHESION-PROMOTING LAYER CHARACTERISED BY DIFFERENT C=O GROUP ABSORPTION MAXIMA

1 . A sheet-like composite ( 100 ), comprising as layers of a layer sequence:

a) an outer polymer layer ( 101 ),

b) a carrying layer ( 102 ) following the outer polymer layer ( 101 ),

c) a barrier layer ( 104 ) following the carrying layer ( 102 ),

d) an adhesion-promoting layer ( 105 ) following the barrier layer ( 104 ), and

e) an inner polymer layer ( 106 ) following the adhesion-promoting layer ( 105 );

wherein the adhesion-promoting layer ( 105 ) comprises an outer surface ( 107 ) of the adhesion-promoting layer and an inner surface ( 108 ) of the adhesion-promoting layer;

wherein the outer surface ( 107 ) of the adhesion-promoting layer

i) is adjacent to the barrier layer ( 104 ), and

ii) is characterised by a first C═O group absorption maximum;

wherein the inner surface ( 108 ) of the adhesion-promoting layer

A) is adjacent to the inner polymer layer ( 106 ),

B) is characterised by a second C═O group absorption maximum, and

C) has a first distance ( 109 ) to the outer surface ( 107 ) of the adhesion-promoting layer;

wherein the first C═O group absorption maximum is higher than the second C═O group absorption maximum.

2 . The sheet-like composite ( 100 ) according to claim 1 , wherein the adhesion-promoting layer ( 105 ) in a first layer level ( 201 ) with a second distance ( 202 ) from the outer surface ( 107 ) of the adhesion-promoting layer has a third C═O group absorption maximum;

wherein the second distance ( 202 ) amounts to 5 to 95% of the first distance ( 109 );

wherein the third C═O group absorption maximum

a) is lower than the first C═O group absorption maximum, and

b) is higher than the second C═O group absorption maximum.

3 . The sheet-like composite ( 100 ) according to claim 1 , wherein the first C═O group absorption maximum is in a range from 0.1 to 5.

4 . The sheet-like composite ( 100 ) according to claim 1 , wherein the second C═O group absorption maximum is in a range of more than 0 to 1.

5 . The sheet-like composite ( 100 ) according to claim 2 , wherein the third C═O group absorption maximum is in a range from 0.015 to 4.5.

6 . The sheet-like composite ( 100 ) according to claim 2 , wherein the second distance ( 202 ) amounts to 5 to 20% of the first distance ( 109 ),

wherein the third C═O group absorption maximum is in a range from 0.05 to 4.5.

7 . The sheet-like composite ( 100 ) according to claim 2 , wherein the second distance ( 202 ) amounts to 50 to 95% of the first distance ( 109 ),

wherein the third C═O group absorption maximum is in a range from 0.015 to 1.2.

8 . The sheet-like composite ( 100 ) according to claim 2 , wherein the adhesive layer ( 105 ) in a further layer plane ( 301 ) with a third distance ( 302 ) of the adhesion-promoting layer outer surface ( 107 ) a fourth C═O group absorption maximum has;

wherein the third distance ( 302 ) is longer than the second distance ( 202 );

wherein the fourth C═O group absorption maximum

a) is lower than the third C═O group absorption maximum, and

b) is higher than the second C═O group absorption maximum.

9 . The sheet-like composite ( 100 ) according to claim 1 , wherein a C═O group absorption maximum of the adhesion-promoting layer ( 105 ) along a straight line ( 501 ) from the outer surface ( 107 ) of the adhesion-promoting layer to the inner surface ( 108 ) of the adhesion-promoting layer decreases in at least two stages ( 500 ).

10 . The sheet-like composite ( 100 ) according to claim 1 , wherein one selected from the group consisting of the first C═O group absorption maximum, the second C═O group absorption maximum, the third C═O group absorption maximum, and the fourth C═O group absorption maximum, or a combination of at least two thereof, is an absorption maximum of C═O groups, wherein the C═O groups comprise functional groups selected from the group consisting of carboxylic acid groups, a salt of the carboxylic acid groups, carboxylic anhydride groups, or a combination of at least two thereof.

11 . The sheet-like composite ( 100 ) according to claim 1 , wherein one selected from the group consisting of the first C═O group absorption maximum, the second C═O group absorption maximum, the third C═O group absorption maximum, and the fourth C═O group absorption maximum, or a combination of at least two thereof is an absorption maximum of a functional group, wherein the functional group is a repeating unit based on a monomer selected from the group consisting of acrylic acid, a salt of acrylic acid, methacrylic acid, a salt of methacrylic acid, an acrylic acid ester, maleic acid, and maleic anhydride, or a combination of at least two thereof.

12 . The sheet-like composite ( 100 ) according to claim 1 , wherein the polymer inner layer ( 106 ) contains at least 30 wt.-%, respective to the total weight of the inner polymer layer ( 106 ) of a polymer produced by means of a metallocene catalyst.

13 . The sheet-like composite ( 100 ) according to claim 1 , wherein the inner polymer layer ( 106 ), is a mixture comprising a polymer produced by means of a metallocene catalyst and an additional polymer.

14 . The sheet-like composite ( 100 ) according to claim 1 , wherein the carrying layer ( 102 ) contains one material selected from the group consisting of cardboard, paperboard, and paper, or a combination of at least two thereof.

15 . The sheet-like composite ( 100 ) according to claim 1 , wherein the barrier layer ( 104 ) comprises one material selected from the group consisting of a plastic, a metal, and a metal oxide, or a combination of at least two thereof.

16 . The sheet-like composite ( 100 ) according to claim 1 , wherein the carrying layer ( 102 ) has at least one hole,

where the hole is covered with at least the barrier layer ( 104 ) and at least the polymer inner layer ( 106 ) as hole covering layers.

17 . The sheet-like composite ( 100 ) according to claim 1 , wherein the first distance ( 109 ) is more than one layer thickness of the inner polymer layer ( 106 ).

18 . The sheet-like composite ( 100 ) according to claim 1 , wherein the sheet-like composite ( 100 ) is rolled up into a coil with at least two layers of the sheet-like composite ( 100 ).

19 . A process ( 1000 ), comprising as process steps ( 1001 , 1002 , 1003 ):

a) the provision of a composite precursor, comprising as layers of a layer sequence:

i) an outer polymer layer ( 101 ),

ii) a carrying layer ( 102 ) following the outer polymer layer ( 101 ), and

iii) a barrier layer ( 104 ) following the carrying layer ( 102 );

b) superimposing an adhesion-promoting layer ( 105 ) on the barrier layer ( 104 ) on a side facing away from the carrying layer ( 102 );

c) superimposing an inner polymer layer ( 106 ) on the adhesion-promoting layer ( 105 ) on a side facing away from the barrier layer ( 104 );

wherein the adhesion-promoting layer ( 105 ) comprises an outer surface ( 107 ) of the adhesion-promoting layer and an inner surface ( 108 ) of the adhesion-promoting layer;

wherein the outer surface ( 107 ) of the adhesion-promoting layer

A) is adjacent to the barrier layer ( 104 ), and

B) is characterised by a first C═O group absorption maximum;

wherein the inner surface ( 108 ) of the adhesion-promoting layer

I) is adjacent to the inner polymer layer ( 106 ),

II) is characterised by a second C═O group absorption maximum, and

III) has a first distance ( 109 ) to the outer surface ( 107 ) of the adhesion-promoting layer;

wherein the first C═O group absorption maximum is higher than the second C═O group absorption maximum.

20 . The process ( 1000 ) according to claim 19 , wherein the adhesion-promoting layer ( 105 ) in a first layer level ( 201 ) with a second distance ( 202 ) from the outer surface ( 107 ) of the adhesion-promoting has a third C═O group absorption maximum;

wherein the second distance ( 202 ) amounts to 5 to 95% of the first distance ( 109 );

wherein the third C═O group absorption maximum

a) is lower than the first C═O group absorption maximum, and

b) is higher than the second C═O group absorption maximum.

21 . The process ( 1000 ) according to claim 19 , wherein in process step b) ( 1002 ) or in process step c) ( 1003 ) or in both, superimposing comprises an extrusion.

22 . The process ( 1000 ) according to claim 21 , wherein the extrusion in process step b) ( 1002 ) comprises a co-extrusion of at least a first polymer melt, a second polymer melt, and a third polymer melt;

wherein prior to process step b) ( 1002 ) the first polymer melt is produced from a first plurality of polymer particles, the second polymer melt is produced from a second plurality of polymer particles, and the third polymer melt is produced from a third plurality of polymer particles;

wherein a C═O group absorption maximum of the first plurality of polymer particles is higher than a C═O group absorption maximum of the third plurality of polymer particles;

wherein the C═O group absorption maximum of the third plurality of polymer particles is higher than a C═O group absorption maximum of the second plurality of polymer particles.

23 . A sheet-like composite, obtainable by the method ( 1000 ) according to claim 19 .

24 . A container precursor ( 800 ) comprising a sheet-like composite ( 100 ) according to claim 1 ,

wherein the sheet-like composite ( 100 ) comprises at least one fold ( 801 ) with at least two adjoining folding surfaces ( 802 , 803 ),

wherein at least one partial section ( 804 ) of the at least two folding surfaces ( 802 , 803 ) is joined by sealing with the respective other partial section ( 804 ).

25 . A process ( 1100 ), comprising as process steps ( 1101 , 1102 , 1103 ):

a) providing the sheet-like composite ( 100 ) according to claim 1 ;

b) folding the sheet-like composite ( 100 ) to form a fold ( 801 ) with at least two adjoining folding surfaces ( 802 , 803 ); and

c) joining at least one partial section ( 804 ) of the at least two folding surfaces ( 802 , 803 ) with the other partial section ( 804 ) by a sealing.

26 . The process ( 1100 ) according to claim 25 , wherein at least a part of the sheet-like composite ( 100 ) has a temperature in a range of 10 to 50° C. during folding.

27 . The process ( 1100 ) according to claim 25 , wherein the sealing is carried out by one selected from the group consisting of irradiation, contact with a hot solid material, inducing a mechanical vibration, and a contact with a hot gas, or a combination of at least two of them.

28 . The process ( 1100 ) according to claim 25 , wherein the sheet-like composite ( 100 ) in process step a) ( 1101 ) comprises at least one crease and in process step b) ( 1102 ) folding is done along the crease.

29 . A container precursor, obtainable by the process ( 1100 ) according to claim 24 .

30 . A closed container ( 900 ) surrounding an interior space ( 901 ), wherein the container ( 900 ) comprises the folded sheet-like composite ( 100 ) according to claim 1 .

31 . A process ( 1200 ), comprising as process steps ( 1201 , 1202 ):

a) providing the container precursor ( 800 ) according to claim 24 ; and

b) closing the container precursor ( 800 ) by means a closing tool.

32 . The process ( 1200 ) according to claim 30 , wherein the container precursor ( 800 ) is filled before closing with a food product.

33 . A container obtainable by the process according to claim 31 .

34 . A use of the sheet-like composite ( 100 ) according to claim 1 , for the production of a container.

35 . A use of the container ( 900 ) according to claim 30 for filling a food product into the container ( 900 ).