An adhesive composition containing polyethylene based ionomers

Abstract

The invention relates to an adhesive composition comprising an ethylene polymer. The invention further relates to an adhesive composition comprising specific type of ethylene polymer obtained by ethylene and ion pair compounds polymerization. In addition, the invention relates to a multi- layer article having an adhesive layer comprising the adhesive composition positioned between the layers of the article and to the use of the adhesive composition in the adhesion of the layers of a multi-layer article.

Description

23POLY0061-WO-ORD 1 AN ADHESIVE CONTAINING POLYETHYLENE BASED IONOMERS FIELD OF INVENTION

[0001] The invention relates to an ethylene polymer based adhesive composition. The invention further relates to an adhesive composition comprising an ethylene polymer comprising polymeric units derived from ethylene and ion pair compounds. In addition, the invention relates to the use of adhesive composition in the adhesion of the layers of a multi-article. BACKGROUND

[0002] Due to the high hydrophobic nature of ethylene polymers, are not suited for certain applications, such as heat sealing or adhesive bonding. Unless such polymers are surface treated, polyolefins as adhesives are hardly effective especially while boding different metal surfaces. Surface treatment for example can be used for improving the adhesive properties of ethylene polymers. These techniques typically involve ways to chemically alter very thin surface layers without altering the bulk polymer properties and typically involves processes such as of corona discharge, flame treatment, oxidation by acids and chlorination. Although these processes can be effective, they are expensive, energy intensive and therefore often not sustainable from cost and environmental point of view. As an additional consideration, there is always a chance of damaging the polymer itself during the process of surface treatment.

[0003] On the other hand, structural adhesives, such as rubber and epoxy adhesives, have certain properties that make them suitable for use in a variety of applications that require adhesion to metal or polymer components for various applications such as use in the automotive or electronic industry. However, for such adhesives, recycling or reprocessing such structural adhesives render handling and recycling such adhesives are difficult. Besides longer to cure, will require surface preparation, and can carry health and safety concerns. Further, in the past, crosslinking agents are added to a polymer system to improve its adhesive properties. Addition of such crosslinking agents not only make recycling of the polymer difficult but also may result in the generation of by-products which are difficult to purify.

[0004] Therefore, it is an object of the present invention, to provide an adhesive composition comprising an ethylene polymer having excellent adhesive properties without the need for surface treating the adhesive composition for joining metal and plastic parts. Yet another23POLY0061-WO-ORD 2 object of the present invention is to have layer articles having different layers adhered together with excellent adhesion while providing the desired structural properties. Yet another object of the present invention is to have multi-layer articles which can be recycled with relative ease. DESCRIPTION

[0005] Accordingly, the one or more objectives of the present invention is achieved by adhesive composition, comprising > 90.0 wt.%, preferably ≥ 95.0 wt.%, of an ethylene polymer with regard to the total weight of the adhesive composition, wherein the ethylene polymer comprises or consists of: (a) polymeric units derived from ethylene; and (b) polymeric units derived from a cationic monomer represented by formula (I) ^hydrogen or an alkyl group having 1-10 carbon atoms, preferably 1-5 carbon atoms; ^ ‘X’ is independently selected from ‘O’ or ‘NH’, preferably ‘X’ is ‘O’; ^ R2 is an alkyl group having 1-40 carbon atoms, preferably 1-5 carbon atoms; ^ R3and R4are each independently selected from hydrogen or an alkyl group having 1-10 carbon atoms, preferably 1-5 carbon atoms; and ^ R5is independently selected from hydrogen or an alkyl group having 1-20 carbon atoms, preferably 1-5 carbon atoms, ^ preferably wherein each of R3 and R4 is an alkyl group having 1-5 carbon atoms and R5is hydrogen; and (c) polymeric units derived from at least one anionic monomer selected from the formula below,23POLY0061-WO-ORD 3 ^ wherefrom hydrogen or an alkyl group having 1-10 carbon atoms; ^ R8and R10are each independently selected from alkyl group having 1-40 carbon atoms; ^ ‘Y’, ‘V’ and ‘W’ is independently selected from ‘O’ or ‘NH’; ‘n’ is a number ranging from 1 to 20; ‘Z’ is independently selected from -SO3or -C(O)O; ^ preferably wherein the anionic monomer is (II) where R6is an alkyl group having 1-5 carbon atoms, and23POLY0061-WO-ORD 4 ^ the cationic monomer is where ‘X’ is ‘O’, and eachof R2, R3and R4is an and R5is hydrogen; (i) wherein the total content (IPC) of polymeric units derived from the cationic monomer and the anionic monomer ranges from ≥ 1.0 and ≤ 30.0 wt.%, preferably ≥ 1.5 and ≤ 20.0 wt.%, preferably ≥ 3.0 and ≤ 15.0 wt.%, preferably ≥ 3.0 and ≤ 12.0 wt.%, preferably ≥ 6.0 and ≤ 12.0 wt.% with regard to the total weight of the ethylene polymer; and (ii) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 0.1 and ≤ 100 dg / min, preferably ≥ 0.45 and ≤ 40.0 dg / min, preferably ≥ 1.0 and ≤ 30.0 dg / min, preferably ≥ 5.0 and ≤ 30.0 dg / min, preferably ≥ 5.0 and ≤ 25.0 dg / min, preferably ≥ 5.0 and ≤ 15.0 dg / min, preferably ≥ 5.0 and ≤ 14.0 dg / min, preferably ≥ 5.0 and ≤ 10.0 dg / min where MFI2is the melt flow index determined in accordance with ISO1133- 1:2011 at 190 ºC and measured at 2.16 kg; and (iii) wherein the value of MFI2 / IPC is > 0 and ≤ 3.3, preferably > 0 and ≤ 3.0, preferably > 0 and ≤ 2.5, preferably > 0 and ≤ 1.5, preferably ≥ 0.2 and ≤ 1.5, preferably > 0.5 and ≤ 1.0, where IPC and MFI2 are as defined herein.

[0006] Preferably, the adhesive composition, comprises > 90.0 wt.%, preferably ≥ 95.0 wt.%, of the ethylene polymer with regard to the total weight of the adhesive composition, wherein the ethylene polymer comprises or consists of: (a) polymeric units derived from ethylene; and (b) polymeric units derived from a cationic monomer represented by formula (I)POLY0061-WO-ORD 5 ^hydrogen or an alkyl group having 1-10 carbon atoms, preferably 1-5 carbon atoms; ^ ‘X’ is independently selected from ‘O’ or ‘NH’, preferably ‘X’ is ‘O’; ^ R2 is an alkyl group having 1-40 carbon atoms, preferably 1-5 carbon atoms; ^ R3and R4are each independently selected from hydrogen or an alkyl group having 1-10 carbon atoms, preferably 1-5 carbon atoms; and ^ R5 is independently selected from hydrogen or an alkyl group having 1-20 carbon atoms, preferably 1-5 carbon atoms, ^ preferably wherein each of R3 and R4 is an alkyl group having 1-5 carbon atoms and R5 is hydrogen; and (c) polymeric units derived from at least one anionic monomer selected from the formula below,23POLY0061-WO-ORD 6 ^ wherefrom hydrogen or an alkyl group having 1-10 carbon atoms; ^ R8 and R10 are each independently selected from alkyl group having 1-40 carbon atoms; ^ ‘Y’, ‘V’ and ‘W’ is independently selected from ‘O’ or ‘NH’; ‘n’ is a number ranging from 1 to 20; ‘Z’ is independently selected from -SO3 or -C(O)O; ^ preferably wherein the anionic monomer is (II) where R6 is an alkyl group having 1-5 carbon atoms, and^ the cationic monomer is where ‘X’ is ‘O’, and eachof R2, R3and R4is an and R5is hydrogen; (i) wherein the total content (IPC) of polymeric units derived from the cationic monomer and the anionic monomer ranges from ≥ 1.0 and ≤ 30.0 wt.%, with regard to the total weight of the ethylene polymer; and23POLY0061-WO-ORD 7 (ii) wherein the melt flow index of the ethylene polymer ranges from ≥ 0.1 and ≤ 100 dg / min, preferably ≥ 0.45 and ≤ 40.0 dg / min, where MFI2 is the melt flow index determined in accordance with ISO1133-1:2011 at 190 ºC and measured at 2.16 kg; and (iii) wherein the value of MFI2 / IPC is > 0 and ≤ 3.3 where IPC and MFI2 are as defined herein

[0007] Accordingly, the selection of the MFI2and the content of cationic monomer and the anionic monomer (IPC) has to be selected such that the value of MFI2 / IPC is between > 0 and ≤ 3.3, preferably > 0 and ≤ 3.0, preferably > 0 and ≤ 2.5, preferably > 0 and ≤ 1.5, preferably ≥ 0.2 and ≤ 1.5, preferably > 0.5 and ≤ 1.0.

[0008] The polymeric units derived from the cationic monomer and the anionic monomer may be derived from specific ion pair compounds, which is copolymerized with ethylene. It is particularly preferred that the adhesive composition and / or the ethylene polymer is free of cross- linking. Preferably the adhesive composition is substantially free of additives selected from cross- linking agents, talc, carbon black, reinforcing fibers. Surprisingly, the inventors found that even without adding any of such additives, the adhesive composition demonstrated excellent adhesive properties. The term substantially free as used herein means that the concentration of fillers such as talc, carbon black, reinforcing fibers is less than 100 ppm by weight, preferably 50 ppm by weight, preferably 0 ppm by weight of the ethylene polymer.

[0009] Preferably, the adhesive composition, comprises > 90.0 wt.%, preferably ≥ 95.0 wt.%, of the ethylene polymer with regard to the total weight of the adhesive composition, wherein the ethylene polymer comprises or consists of: (a) polymeric units derived from ethylene; (b) polymeric units derived from the anionic monomer represented by formula:23POLY0061-WO-ORD 8 where R6is an alkyl group having 1-5 atoms; and (c) polymeric units derived from the cationic monomer represented by formula: where ‘X’ is ‘O’, and each of R2, R3and R4is an alkyl groupatoms (i) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 1.0 and ≤ 30.0 wt.%, preferably ≥ 1.5 and ≤ 20.0 wt.%, preferably ≥ 3.0 and ≤ 15.0 wt.%, preferably ≥ 3.0 and ≤ 12.0 wt.%, preferably ≥ 6.0 and ≤ 12.0 wt.% with regard to the total weight of the ethylene polymer; and (ii) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 0.1 and ≤ 100 dg / min, preferably ≥ 0.45 and ≤ 40.0 dg / min, preferably ≥ 1.0 and ≤ 30.0 dg / min, preferably ≥ 5.0 and ≤ 30.0 dg / min, preferably ≥ 5.0 and ≤ 15.0 dg / min, preferably ≥ 5.0 and ≤ 14.0 dg / min, preferably ≥ 5.0 and ≤ 10.0 dg / min where MFI2is the melt flow index determined in accordance with ISO1133-1:2011 at 190 ºC and measured at 2.16 kg; and (iii) wherein the value of MFI2 / IPC is > 0 and ≤ 3.3, preferably > 0 and ≤ 3.0, preferably > 0 and ≤ 2.5, preferably > 0 and ≤ 1.5, preferably ≥ 0.2 and ≤ 1.5, preferably > 0.5 and ≤ 1.0, where IPC and MFI2 are as defined herein.

[0010] Preferably, the adhesive composition, comprises > 90.0 wt.%, preferably ≥ 95.0 wt.%, of the ethylene polymer with regard to the total weight of the adhesive composition, wherein the ethylene polymer comprises or consists of: (a) polymeric units derived from ethylene; (b) polymeric units derived from the anionic monomer represented by formula:23POLY0061-WO-ORD 9atoms; and (c) polymeric units derived from the cationic monomer represented by formula: where ‘X’ is ‘O’, and each of R2, R3 and R4 is an alkyl group(i) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 1.0 and ≤ 30.0 wt.%, preferably ≥ 1.5 and ≤ 20.0 wt.%, preferably ≥ 3.0 and ≤ 15.0 wt.%, preferably ≥ 3.0 and ≤ 12.0 wt.%, preferably ≥ 6.0 and ≤ 12.0 wt.% with regard to the total weight of the ethylene polymer; and (ii) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 0.1 and ≤ 100 dg / min, preferably ≥ 0.45 and ≤ 40.0 dg / min, preferably ≥ 1.0 and ≤ 30.0 dg / min, preferably ≥ 5.0 and ≤ 30.0 dg / min, preferably ≥ 5.0 and ≤ 15.0 dg / min, preferably ≥ 5.0 and ≤ 14.0 dg / min, preferably ≥ 5.0 and ≤ 10.0 dg / min where MFI2is the melt flow index determined in accordance with ISO1133-1:2011 at 190 ºC and measured at 2.16 kg; and (iii) wherein the value of MFI2 / IPC is > 0 and ≤ 3.3, preferably > 0 and ≤ 3.0, preferably > 0 and ≤ 2.5, preferably > 0 and ≤ 1.5, preferably ≥ 0.2 and ≤ 1.5, preferably > 0.5 and ≤ 1.0, where IPC and MFI2 are as defined herein23POLY0061-WO-ORD 10

[0011] Preferably, the adhesive comprises > 90.0 wt.%, preferably ≥ 95.0 wt.%, of the ethylene polymer with regard to the total weight of the adhesive composition, wherein the ethylene polymer comprises or consists of: (a) polymeric units derived from ethylene; (b) polymeric units derived from the anionic monomer represented by formula:having 1-5 carbon atoms; and (c) polymeric units derived from the cationic monomer represented by formula: where ‘X’ is ‘O’, and each of R2, R3and R4is an alkyl groupatoms (i) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 3.0 and ≤ 15.0 wt.%, preferably ≥ 3.0 and ≤ 12.0 wt.%, preferably ≥ 6.0 and ≤ 12.0 wt.% with regard to the total weight of the ethylene polymer; and (ii) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 30.0 dg / min, preferably ≥ 5.0 and ≤ 15.0 dg / min, preferably ≥ 5.0 and ≤ 14.0 dg / min, preferably ≥ 5.0 and ≤ 10.0 dg / min where MFI2is the melt flow index determined in accordance with ISO1133-1:2011 at 190 ºC and measured at 2.16 kg; and23POLY0061-WO-ORD 11 (iii) wherein the value of MFI2 / IPC is and ≤ 3.0, preferably > 0 and ≤ 2.5, preferably > 0 and ≤ 1.5, preferably ≥ 0.2 and ≤ 1.5, preferably > 0.5 and ≤ 1.0, where IPC and MFI2 are as defined herein.

[0012] Preferably, the adhesive composition, comprises > 90.0 wt.%, preferably ≥ 95.0 wt.%, of the ethylene polymer with regard to the total weight of the adhesive composition, wherein the ethylene polymer comprises or consists of: (a) polymeric units derived from ethylene; (b) polymeric units derived from the anionic monomer represented by formula:having 1-5 carbon atoms; and (c) polymeric units derived from the cationic monomer represented by formula: where ‘X’ is ‘O’, and each of R2, R3and R4is an alkyl group(i) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 3.0 and ≤ 12.0 wt.%, preferably ≥ 6.0 and ≤ 12.0 wt.% with regard to the total weight of the ethylene polymer; and (ii) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 14.0 dg / min, preferably ≥ 5.0 and ≤ 10.0 dg / min where MFI2is the melt flow index23POLY0061-WO-ORD 12 determined in accordance with 1:2011 at 190 ºC and measured at 2.16 kg; and (iii) wherein the value of MFI2 / IPC is ≥ 0.2 and ≤ 1.5, preferably > 0.5 and ≤ 1.0, where IPC and MFI2are as defined herein.

[0013] Preferably, R2 is ethyl, R5 is hydrogen and R3 and R4 are methyl group. Preferably, R2 is ethyl, R5 is hydrogen and R3 and R4 are methyl group. Preferably, R2 is ethyl, R5 is hydrogen and R3is t-butyl and R4is a hydrogen. Preferably, R2is ethyl and R3, R4and R5are hydrogen.

[0014] Advantageously, the adhesive composition demonstrates excellent adhesive properties to different substrate surfaces while retaining desired mechanical stress properties. As a further advantage, the adhesive strength is particularly suitable to provide the necessary adhesion and ensuring structural integrity of an article is maintained but also suitable for the layers adhered together in a multi-layer article to be delaminated during recycling with relative ease. As a further advantage, the adhesive composition demonstrates excellent adhesion without the need of using crosslinking the ethylene polymer.

[0015] As a further advantage, the adhesive composition of the present invention is particularly suitable for adhering different surfaces or substrates especially in a multi-layer article, especially under high temperature conditions.

[0016] In an aspect of the invention, the invention relates to the use of the adhesive composition according to according to the present invention, for improving the adhesion between two substrate layers of a multi-layered article even when exposing the substrate layers at a temperature of > 60oC while retaining the tensile stress property of the multilayered article, preferably wherein each of the substrate layer is a metal, preferably aluminum. In another aspect of the invention, the invention relates to the use of the ethylene polymer as described in the present invention for making an adhesive composition.

[0017] The value of MFI2 / IPC is indicative of the fact that a suitable selection of an ethylene polymer needs to be made having a desired combination of melt flow index the amount of polymeric units derived the anionic and cationic monomer.

[0018] The ethylene polymer has (i) total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranging from ≥ 1.0 and ≤ 30.0 wt.%, preferably ≥ 1.5 and ≤ 20.0 wt.%, preferably ≥ 3.0 and ≤ 15.0 wt.%, preferably ≥ 3.0 and ≤ 12.0 wt.%,23POLY0061-WO-ORD 13 preferably ≥ 6.0 and ≤ 12.0 wt.%, with regard the total weight of the ethylene polymer; and (ii) a total content of polymeric units derived from ethylene ranging from ≥ 70.0 and ≤ 99.0 wt.%, preferably ≥ 80.0 and ≤ 98.5 wt.%, preferably ≥ 85.0 and ≤ 97.0 wt.%, preferably ≥ 88.0 and ≤ 97.0 wt.%, preferably ≥ 88.0 and ≤ 94.0 wt.%, with regard to the total weight of the ethylene polymer.

[0019] Preferably the ethylene polymer has (i) total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranging from ≥ 3.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (ii) a total content of polymeric units derived from ethylene ranging from ≥ 88.0 and ≤ 97.0 wt.%, with regard to the total weight of the ethylene polymer.

[0020] Preferably the ethylene polymer has (i) total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranging from ≥ 6.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (ii) a total content of polymeric units derived from ethylene ranging from ≥ 88.0 and ≤ 94.0 wt.%, with regard to the total weight of the ethylene polymer.

[0021] Preferably, the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 15.0 dg / min, preferably ≥ 5.0 and ≤ 14.0 dg / min; and (b) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 3.0 and ≤ 15.0 wt.%, preferably ≥ 6.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (c) wherein the value of MFI2 / IPC is > 0 and ≤ 2.0, preferably ≥ 0 and ≤ 1.5, preferably > 0 and ≤ 1.0, preferably ≥ 0.3 and ≤ 1.0, preferably > 0.5 and ≤ 1.0, where IPC and MFI2 are as defined herein.

[0022] Preferably, the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 14.0 dg / min, preferably ≥ 5.0 and ≤ 10.0 dg / min; and (b) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 6.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (c) wherein the value of MFI2 / IPC is > 0 and ≤ 1.0, preferably ≥ 0.3 and ≤ 1.0, preferably > 0.5 and ≤ 1.0, where IPC and MFI2 are as defined herein.

[0023] Preferably, the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 10.0 dg / min; and (b) wherein the total content of polymeric units derived from the cationic23POLY0061-WO-ORD 14 monomer and the anionic monomer (IPC) from ≥ 6.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (c) wherein the value of MFI2 / IPC is ≥ 0.3 and ≤ 1.0, where IPC and MFI2are as defined herein.

[0024] Preferably, the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 10.0 dg / min; and (b) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 6.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (c) wherein the value of MFI2 / IPC is > 0.5 and ≤ 1.0, where IPC and MFI2 are as defined herein.

[0025] The purposeful combination of the features of the ethylene polymer of (i) the total content of polymeric units that are derived from the cationic monomer and the anionic monomer (IPC) and (ii) the melt flow index (MFI2) of the ethylene polymer, such that the value of MFI2 / IPC is > 0 and ≤ 3.3, – imparts the desired adhesive and mechanical properties of the adhesive composition.

[0026] It is particularly preferred that the anionic monomer is where R6is an alkyl group having 1-5 carbon atoms, andthe cationic monomer is where ‘X’ is ‘O’, and each of R2, R3and R4 is an alkyl group hydrogen, wherein (a) the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 10.0 dg / min; and (b) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 6.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (c) wherein the value of MFI2 / IPC is > 0 and ≤ 1.0, preferably ≥ 0.3 and ≤ 1.0, preferably > 0.5 and ≤ 1.0, where IPC and MFI2are as defined herein.23POLY0061-WO-ORD 15

[0027] The adhesive composition comprise > 90.0 wt.%, preferably ≥ 95.0 wt.%, preferably ≥ 97.0 wt.%, preferably 100 wt.% of the ethylene polymer with regard to the total weight of the adhesive composition. Preferably the adhesive composition comprises 100 wt.% of the ethylene polymer.

[0028] Preferably, the adhesive composition comprises ≥ 95.0 and ≤ 100 wt.% of the ethylene polymer and ≥ 0.0 wt.% and ≤ 5.0 wt.% of additives. Non-limiting examples of additives include stabilisers, color pigments, anti-oxidants and combinations thereof. Cationic monomer

[0029] The cationic monomer represented by formula (I) may be derived from the quaternarized form of a free base selected from the group consisting of: 2-(dimethylamino)ethyl acrylate, 2-(diethylamino)ethyl acrylate, 2-(diethylamino)ethyl methacrylate, 2-(dimethylamino)ethyl methacrylate, 2-(tert-butylamino)ethyl methacrylate, N-[3-(hexahydro-1 H-azepin-1 -yl)-1,1-dimethylpropyl]-2-propenamide, N-[2-(tetrahydro-1 ,4-oxazepin-4(5H)-yl)ethyl]- 2-propenamide, N-[2-[methyl(tetrahydro-2H-pyran-4-yl)amino]ethyl]- 2-propenamide, N-[3-(hexahydro-4-methyl-1 H-1 ,4-diazepin-1 -yl)propyl]- 2-propenamide, N-[1 -methyl-2-(methylamino)propyl]- 2-propenamide, N-[2-(methylamino)propyl]- 2-propenamide, N-[2-methyl-2-(methylamino)propyl]- 2-propenamide, N-[1 -methyl-2-(methylamino)ethyl]- 2-propenamide, N-[1 -methyl-3-(methylamino)butyl]- 2-propenamide, and N-[1 -methyl-2-(methylamino)propyl]- 2-propenamide.

[0030] Preferably wherein the cationic monomer of formula (I) is derived from the quaternarized form of the free base selected from the group consisting of 2-(dimethylamino)ethyl acrylate, 2-(diethylamino)ethyl acrylate, 2-(diethylamino)ethyl methacrylate, 2- (dimethylamino)ethyl methacrylate, and 2-(tert-butylamino)ethyl methacrylate.23POLY0061-WO-ORD 16

[0031] The term “quaternarized form the free base” means the quaternary compound formed from the free base. Anionic monomer

[0032] The anionic monomer may be derived from the deprotonated form of a free acid selected from the group consisting of: acrylic acid, methacrylic acid, 2-methyl-2-[(1 -oxo-2-propen-1 -yl)amino]- 1 -propanesulfonic acid, 2-methyl-1 -[(1 -oxo-2-propen-1 -yl)amino]- 1 -propanesulfonic acid, 1 -[(1 -oxo-2-propen-1 -yl)amino]-2-butanesulfonic acid 2-[(2-methyl-1 -oxo-2-propen-1 -yl)amino]-2-propanesulfonic acid, 1 -[(1 -oxo-2-propen-1 -yl)amino]-ethanesulfonic acid, 2-(phosphonooxy)ethylester-2-propenoic acid, 2-propenoic acid, 2-methyl-, 2-(phosphonooxy)ethyl ester, 2-methyl-, 1 -methyl-3-(phosphonooxy)propyl ester-2-propenoic acid, 2-methyl-, 1 -[(phosphonooxy)methyl]propyl ester-2-propenoic acid, 2-methyl-N-[7-(phosphonooxy)heptyl]- 2-propenamide, 4-(phosphonooxy)butyl ester-2-propenoic acid, 2-methyl-, 12-(phosphonooxy)dodecyl ester-2-propenoic acid, 2-methyl-, 10-(phosphonooxy)decyl ester-2-propenoic acid, 2-methyl-, 6-(phosphonooxy)hexyl ester-2-propenoic acid, 2-methyl-, 3-(phosphonooxy)propyl ester-2-propenoic acid, 2-methyl-, 1 -methyl-2-(phosphonooxy)ethyl ester-2-propenoic acid, 3-(phosphonooxy)propyl ester-2-propenoic acid, 2-methyl-, 4-(phosphonooxy)butyl ester-2-propenoic acid, 2-oxo-2-[[[(1 -oxo-2-propen-1 -yl)amino]methyl]amino]-ethanesulfonic acid, and 2-[[[(2-methyl-1 -oxo-2-propen-1 -yl)amino]methyl]amino]-2-oxo-ethanesulfonic acid;

[0033] Preferably, the anionic monomer is derived from the deprotonated form of any one of acrylic acid, or methacrylic acid.23POLY0061-WO-ORD 17

[0034] Preferably, the anionic is derived from the deprotonated form of any one of acrylic acid, or methacrylic acid; and wherein the cationic monomer is derived from the quaternarized form of the free base selected from the group consisting of 2-(dimethylamino)ethyl acrylate, 2-(diethylamino)ethyl acrylate, 2-(diethylamino)ethyl methacrylate, 2- (dimethylamino)ethyl methacrylate, and 2-(tert-butylamino)ethyl methacrylate.

[0035] Preferably, the cationic monomer is derived from the quaternarized form of 2- (dimethylamino)ethyl methacrylate and the anionic monomer is derived from the deprotonated form of methacrylic acid.

[0036] Preferably, the cationic monomer is derived from the quaternarized form of 2- (dimethylamino)ethyl methacrylate and the anionic monomer is derived from the deprotonated form of methacrylic acid (a) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 10.0 dg / min; and (b) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 6.0 and ≤ 12.0 wt.%; and (c) wherein the value of MFI2 / IPC is > 0.5 and < 1.0, where IPC and MFI2are as defined herein. Preparation of the ethylene polymer

[0037] The ethylene polymer is obtained by copolymerizing ethylene with cationic monomer and the anionic monomer. It is preferred that the cationic monomer and the anionic monomer is in the form of ion pair compound, with the opposite charges counter balancing each other. The term “ion pair compound” as used herein means ion pair compound according to patent application WO2021009274A1.

[0038] For example, the cationic monomer and the anionic monomer can be of the form given as the form below: with the cationic monomer is represented by themethacrylate and the anionic monomer is represented by the deprotonated form of methacrylic acid.

[0039] The ionic pair compound may also be represented by the formula below:23POLY0061-WO-ORD 18 monomer represented by the quaternary formthe anionic monomer is represented by the deprotonated form of methacrylic acid.

[0040] The ionic pair compound may also be represented by the formula below: with the cationic monomer represented by themethacrylate and the anionic monomer is represented by the deprotonated form of methacrylic acid.

[0041] The ion pair compound may be denoted as: OOOO OO

[0043] Preferably the ethylene polymer used in the present application is obtained by copolymerizing ethylene and an ion pair compound consisting of a cation of formula (I) and an acid anion of formula (II).

[0044] It is preferred that the cationic monomer and the anionic monomer are present in the ethylene polymer in a stoichiometric amount. Preferably the cationic monomer and the anionic23POLY0061-WO-ORD 19 monomer are present in a stoichiometric a stoichiometric ratio of 1:1 or 1:2 depending on the ion pair formed. Preferably, the cationic monomer and the anionic monomer is present in a stoichiometric ratio of 1:1.

[0045] The ion pair compound according to the invention can be dissolved in various types of common polar organic solvents such as isopropanol, acetonitrile, ethyl acetate and injected in the polymerization reactor as a solution.

[0046] The copolymerization may be performed under known processes. The present inventors found that the ethylene polymer as used in the adhesive composition according to the invention is obtained when the polymerization is carried out using a combination of suitable amounts of free-radical initiator, optionally chain transfer agent (CTA) and conducting the polymerization at a suitable temperature.

[0047] Preferably, the ethylene polymer according to the invention are produced in a high- pressure free-radical polymerization process. An advantage of polymerization in such high-pressure free-radical process is that the polymerisation may be performed without the need for a catalyst being present. This allows for the use of certain comonomers such as polar comonomers which are not suitable as comonomers in the production of ethylene copolymers via catalytic processes such as using Ziegler-Natta type catalysts because of the interference with such catalyst.

[0048] A further advantage of preparation of the ethylene polymer according to the invention in a high-pressure free-radical polymerisation process is that such polymerisation results in ethylene polymers having a certain degree of long-chain branching. In order to qualify for certain applications, including extrusion coating application, ethylene polymers are required to have a certain degree of such long-chain branching. The presence of such long-chain branching is understood to contribute to the desired melt processing properties. Accordingly, it is preferred that the ethylene copolymer according to the present invention is prepared via a high-pressure free- radical polymerisation process.

[0049] The pressure in such high-pressure free-radical polymerization process preferably is in the range of ≥ 180 MPa and ≤ 350 MPa, preferably ≥ 190 MPa and ≤ 310 MPa, preferably ≥ 190 MPa and ≤ 310 MPa, preferably ≥ 200 MPa and ≤ 300 MPa. The temperature in such high- pressure free-radical polymerisation process preferably is in the range of ≥ 150 ºC and ≤ 310 ºC,23POLY0061-WO-ORD 20 preferably ≥ 170 ºC and ≤ 290 ºC, preferably ≥ ºC and ≤ 220 ºC, preferably ≥ 170 ºC and ≤ 210 ºC.

[0050] In an aspect of the present invention, the invention relates to an article comprising the adhesive composition comprising the ethylene polymer obtained or obtainable by the process of the present invention.

[0051] Such high-pressure free-radical polymerization process may for example be performed in a tubular reactor or an autoclave reactor. The tubular reactor may for example be a reactor such as described in Nexant PERP Report 2013-2, ’Low Density Polyethylene’, pages 31- 48.

[0052] Such tubular reactor may for example be operated at pressures ranging from 150 to 300 MPa. The tubular reactor may have a tube length of for example ≥ 1000 m and ≤ 5000 m. The tubular reactor may for example have a ratio of length to inner diameter of ≥ 1000:1, alternatively ≥ 10000:1, alternatively ≥ 25000:1, such as ≥ 10000:1 and ≤ 50000:1, alternatively ≥ 25000:1 and ≤ 35000:1. The residence time in the tubular reactor may for example be ≥ 30 s and ≤ 300 s, alternatively ≥ 60 s and ≤ 200 s.

[0053] Such tubular reactors may for example have an inner tubular diameter of ≥ 0.01 m and ≤ 0.20 m, alternatively ≥ 0.05 m and ≤ 0.15 m. The tubular reactor may for example have one or more inlet(s) and one or more outlet(s). The feed composition may for example be fed to the tubular reactor at the inlet of the tubular reactor. The stream that exits the tubular reactor from the outlet may for example comprise the ethylene copolymer. The stream that exits the tubular reactor from the outlet may for example comprise unreacted feed composition. Such unreacted feed compositions may be recycled back into the tubular reactor via one or more inlet.

[0054] The high-pressure free-radical polymerisation process is performed in the presence of one or more free-radical initiator. Preferably, the free-radical initiator is selected from organic peroxides and / or azo compounds.

[0055] Preferably the free radical initiator composition is selected from 2,5-dimethyl-2,5- di(tert-butylperoxy)hexane, t-butyl peroxy pivalate (t-BPP) and / or t-butyl peroxy benzoate (t-BPB).

[0056] Such initiators may for example be fed to the tubular reactor in a pure form or as a solution in a solvent. As solvent, for example a C2-C20 normal paraffin or C2-C20 isoparaffin may be used. For example, such solution may comprise ≥ 2.0% and ≤ 65.0 % by weight of initiator,23POLY0061-WO-ORD 21 alternatively ≥5.0% and ≤40.0% by weight, ≥10.0% and ≤30.0% by weight, compared to the total weight of the solution.

[0057] In addition, further modifiers may be fed to the tubular reactor. Examples of such modifiers may include inhibitors, scavengers and / or chain transfer agents, such as alcohols, aldehydes, ketones and aliphatic hydrocarbons. Such modifiers may for example be fed to the tubular reactor in a pure form or as a solution in a solvent.

[0058] Preferably, the polymerization is performed in the presence of a chain transfer agent selected from the group consisting of methanol, propionaldehyde, n-heptane, propanal, isopropanol and acetone.

[0059] Preferably, the invention relates a process of preparing the adhesive composition, wherein the process comprises the step of polymerizing in a high pressure reactor, ethylene with the cationic monomer represented by formula (I) and with the one or more anionic monomer represented by formula (II), (III), (IV) and (V) to obtain the ethylene polymer and optionally mixing the ethylene polymer and additives to obtain the adhesive composition; and wherein the polymerization is carried out in a high pressure reactor: ^ at a temperature of ≥ 150 ºC and ≤ 310 ºC, preferably ≥ 170 ºC and ≤ 290 ºC, preferably ≥ 170 ºC and ≤ 220 ºC, preferably ≥ 170 ºC and ≤ 210 ºC; and ^ at a pressure of ≥ 180 MPa and ≤ 350 MPa, preferably ≥ 190 MPa and ≤ 310 MPa, preferably ≥ 190 MPa and ≤ 310 MPa, preferably ≥ 200 MPa and ≤ 300 MPa; and ^ in presence of one or more free-radical initiator present in an amount of ≥ 0.3 milli mol.% and ≤ 1.1 milli mol.%, with regard to total amount of ethylene monomer in the high pressure reactor; and ^ optionally in presence of one or more chain transfer agent (CTA) present in an amount of > 0.01 and < 0.1 mol%, preferably ≥ 0.05 and ≤ 0.1 mol%, with regard to total amount of ethylene monomer in the high pressure reactor.

[0060] It is preferred that the temperature is ≥ 170 ºC and ≤ 220 ºC, preferably ≥ 170 ºC and ≤ 210 ºC and pressure ≥ 190 MPa and ≤ 210 MPa. Article - Multi-layer article -23POLY0061-WO-ORD 22

[0061] In an aspect of the invention invention is related to an article comprising a substrate layer and an adhesive layer in contact with at least a portion of the substrate layer, wherein the adhesive layer comprises ≥ 95.0 wt.% preferably 100. wt.%, with regard to the total weight of the adhesive layer, of the adhesive composition according to the invention.

[0062] Preferably the article is a multi-layer article comprising a first substrate layer, a second substrate layer and an adhesive layer comprising ≥ 95.0 wt.%, preferably 100 wt.%, with regard to the total weight of the adhesive layer, of the adhesive composition according to the present invention, wherein adhesive layer is in contact with at least a portion of the first substrate layer and at least a portion of the second substrate layer and wherein the adhesive layer is positioned between the first substrate layer and the second substrate layer.

[0063] The adhesive layer may have a thickness of 1 nm to 1 cm, preferably 100 nm to 200 mm, preferably 200 nm to 1 cm.

[0064] Preferably, the adhesive layer comprises the adhesive composition comprising > 90.0 wt.%, preferably ≥ 95.0 wt.%, of the ethylene polymer with regard to the total weight of the adhesive composition, wherein the ethylene polymer comprises or consists of: (a) polymeric units derived from ethylene; and (b) polymeric units derived from the cationic monomer represented by formula (I) ^hydrogen or an alkyl group having 1-10 carbon atoms, preferably 1-5 carbon atoms; ^ ‘X’ is independently selected from ‘O’ or ‘NH’, preferably ‘X’ is ‘O’; ^ R2 is an alkyl group having 1-40 carbon atoms, preferably 1-5 carbon atoms; ^ R3and R4are each independently selected from hydrogen or an alkyl group having 1-10 carbon atoms, preferably 1-5 carbon atoms; and23POLY0061-WO-ORD 23 ^ R5 is independently selected hydrogen or an alkyl group having 1-20 carbon atoms, preferably 1-5 carbon atoms, ^ preferably wherein each of R3and R4is an alkyl group having 1-5 carbon atoms and R5 is hydrogen; and (c) polymeric units derived from at least one anionic monomer selected from the formula below, ^ wherefrom hydrogen or an alkyl group having 1-10 carbon atoms; ^ R8 and R10 are each independently selected from alkyl group having 1-40 carbon atoms; ^ ‘Y’, ‘V’ and ‘W’ is independently selected from ‘O’ or ‘NH’; ‘n’ is a number ranging from 1 to 20; ‘Z’ is independently selected from -SO3or -C(O)O;23POLY0061-WO-ORD 24 ^ preferably wherein the anionic monomer is alkyl group having 1-5 carbon atoms, and^ the cationic monomer is where ‘X’ is ‘O’, and each of R , R and R is a2 3 4 n and R5 is hydrogen; (i) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 1.0 and ≤ 30.0 wt.%, preferably ≥ 1.5 and ≤ 20.0 wt.%, preferably ≥ 3.0 and ≤ 15.0 wt.%, preferably ≥ 3.0 and ≤ 12.0 wt.%, preferably ≥ 6.0 and ≤ 12.0 wt.% with regard to the total weight of the ethylene polymer; (ii) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 0.1 and ≤ 100 dg / min, preferably ≥ 0.45 and ≤ 40.0 dg / min, preferably ≥ 1.0 and ≤ 30.0 dg / min, preferably ≥ 5.0 and ≤ 30.0 dg / min, preferably ≥ 5.0 and ≤ 15.0 dg / min, preferably ≥ 5.0 and ≤ 14.0 dg / min, preferably ≥ 5.0 and ≤ 10.0 dg / min where MFI2is the melt flow index determined in accordance with ISO1133-1:2011 at 190 ºC and measured at 2.16 kg; and (iii) wherein the value of MFI2 / IPC is > 0 and ≤ 3.3, preferably > 0 and ≤ 3.0, preferably > 0 and ≤ 2.5, preferably > 0 and ≤ 1.5, preferably ≥ 0.2 and ≤ 1.5, preferably > 0.5 and ≤ 1.0, where IPC and MFI2 are as defined herein.

[0065] The adhesive layer is positioned between the first substrate layer and the second substrate layer. The adhesive layer can be added by any suitable method such as spray coating or by extrusion coating between the substrate layers.23POLY0061-WO-ORD 25

[0066] Preferably, the first substrate is identical or different from the second substrate layer and wherein first substrate layer and / or second layer is a selected from any one of metal, glass, ceramic or plastic.

[0067] It is particularly preferred that the first substrate layer and the second layer is a metal.

[0068] Preferably the article is a multi-layered article and wherein the first substrate layer and / or second layer is a plastic selected from polypropylene, polyethylene, polystyrene, polycarbonate, polyvinylchloride, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyphenylene sulfide, polyvinyl alcohol, polyester, polyether, polyvinyl acetate, polyethylene glycol, polyvinylidene fluoride, polytetrafluoroethylene, styrene butadiene rubber, polyisoprene, chloroprene rubber, acrylic rubber, polymer having cyano group, urethane rubber, ethylene propylene rubber, epichlorohydrin rubber, butadiene rubber, fluorine rubber, acrylic-vinyl alcohol copolymer, epoxy resin, oxetane resin, urethane resin, acrylic resin, polysaccharide, polyimide, polyamideimide, silicone, cellulose based or a combination thereof. The term polyethylene and ethylene polymer may be used interchangeably.

[0069] Preferably, the first substrate layer and / or second layer is a plastic selected from any one of polypropylene or polyethylene.

[0070] Preferably the article is a multi-layered article and wherein the first substrate layer and / or second substrate layer is a metal selected from Iron, Aluminum, Cobalt, Nickel, Copper, Zinc, Tungsten, Tin, Gold, Silver, Magnesium, Titanium, steel, metal alloy and combination thereof, preferably wherein the first substrate layer and / or second layer is a metal selected from any one of aluminum, or steel, preferably, wherein the first substrate layer and / or second layer is aluminum.

[0071] Preferably, the article is an extrusion coated article, a film, an automobile component, a high pressure pipe, a moulded article, a 3D printed article, a metal article or a polymer alloy and combinations thereof.

[0072] The invention will now be demonstrated with the following non-limiting examples.23POLY0061-WO-ORD 26

[0073] Purpose: To evaluate the adhesion performance of specific ethylene polymers against various substrate surfaces.

[0074] Material: The ethylene polymer were prepared involving copolymerizing ethylene and an ion pair compound of a quaternary compound derived from 2-(dimethylamino)ethyl methacrylate (cationic monomer) and deprotonated methacrylic acid (MA). The properties of the ethylene polymer samples were modified with the amount of polymeric units derived from ethylene and the ion pair compound (IPC) i.e cationic monomer and anionic monomer.

[0075] The samples IE1-IE3 represents the inventive adhesive compositions, in accordance with the present invention while samples CE1 and CE2 were adhesive compositions derived from the ethylene polymer having properties outside the scope of the invention. CE3 represents commercial Low Density Polyethylene (LDPE) polymer procured from SABIC. Preparation of the ion pair compound comprising the cationic monomer an anionic monomer:

[0076] In a round bottom flask having an ice bath, which contained methacrylic acid (510.9 g, 5.935 mol), 2-(dimethylamino)ethyl methacrylate (1000 mL, 5.935 mol) was added dropwise to it while maintaining the temperature below 20 °C. No purification was required and the ion pair compound was obtained at a quantitative yield (1.44 kg, 100%). Preparation of ethylene polymer

[0077] For each of the samples of ion pair compounds the following process was followed The ion pair compound sample so obtained, was dissolved in methanol (50 wt%) and mixed under high-pressure (2000 bars or 200 MPa) with ethylene through a static mixer. Consequently, the peroxide initiator, Luperox®11M75 (1.5 g / L), and propanal as chain transfer agent CTA were added to the mixture and the mixture was heated at 60 °C before being injected in a reactor set at a temperature between 180 °C to 270 °C to obtain the ethylene polymer having polymeric units derived from ethylene and ion pair compound i.e. cationic and anionic monomeric units. The total content of polymeric units (IPC) derived from the cationic monomer and the anionic monomer and melt flow index (MFI2) for the ethylene polymer was determined.

[0078] The reaction scheme may be shown by the diagram below -23POLY0061-WO-ORD 27and the anionic monomer IPC and present in the ethylene polymer were determined using known techniques such as elemental analysis and1H NMR.

[0080] The ethylene polymer obtained was prepared to form an adhesive composition. To prepare the adhesive composition, 10 g of the ethylene polymer powder was pressed in a mold of 10 cm x 10 cm x 0.5 mm at 180 °C, to obtain a sample strip containing the adhesive composition. Three rectangular stripes (12.5 mm x 25 mm x 0.5 mm) were cut and cleaned with EtOH. Table 1 Sample Amount of ion Amount of Total amount of Temperature Total Reference pair compound chain transfer polymeric units (°C) concentration dissolved in agent CTA derived from of Peroxide methanol in the added in the the cationic and Initiator reactor feed reactor feed anionic added (mol%) (mol%) monomer (IPC) (mmol%) (wt.%) with regard to total weight of the ethylene polymer IE1 (P12) 0.1 0.07 6.0 220 0.445 IE2 (P17) 0.2 0 10.0 200 1.07 IE3 (P18) 0.2 0.07 10.5 200 0.7323POLY0061-WO-ORD 28 CE1 (P14) 0.1 0.07 2.8 250 0.839 CE2 (P20) 0.2 0.07 6.1 250 1.494 Adhesion Performance

[0081] To study the adhesion properties of ethylene polymers, lap shear tests were performed according to ASTM D3163-01 involving plastic substrates while ASTM D1002 was followed for metal substrates. For each of the samples the following test procedure was followed:

[0082] For ASTM D3163-01, for preparing the adhesively bonded rigid plastic, two plastic substrates were bonded together with the adhesive compositions prepared from the inventive and comparative samples, and subsequently cured.

[0083] The plastic substrates itself were prepared from SABIC® PP576P homopolymer grade. The polypropylene SABIC® PP576P were used in powder form and pressed at 190 °C with a force of 100 kN (dimensions. 10 x 2.5 cm, thickness 1 mm) and their surfaces were cleaned with EtOH.

[0084] The plastic substrates were placed so that they overlapped with the appropriate area and the strip containing the adhesive composition (with a dimension of: 12.5x25x1 mm) were placed between plastic substrates. The entire setup was placed inside the compression molding machine, and then a force of 100 N and at a temperature of 120 °C was applied for 5 minutes and the lap shear test was performed with a Zwick type Z020 tensile tester equipped with a 1 kN load cell. A grip-to-grip separation of 195 mm was used. The samples were pre-stressed to 0.1 N and with a test speed of 100 mm^min-1.

[0085] For ASTM D1002, two metal substrates (dimensions of 100 mm x 25 mm x 1 mm) was used and their surfaces were cleaned with EtOH. Subsequently, the metal substrates were bonded together with the strip containing the adhesive composition and thereafter cured The metal slabs were placed so that they overlapped with the appropriate area and the polymer films (as described in 0066) were placed between them. The entire setup was placed inside the compression molding machine, and then a force of 100 N and a temperature of 180 °C were applied for 5 minutes. Lap shear tests were performed with a Zwick type Z020 tensile tester equipped with a 123POLY0061-WO-ORD 29 kN load cell. A grip-to-grip separation of was used. The samples were pre-stressed to 0.1 N and with a test speed of 100 mm^min-1.

[0086] For the metal substrate, aluminum and steel bars were used as substrate surfaces, and the surface was carefully cleaned with EtOH. Aging test:

[0087] Initial conditions: 168 hours at (23 ± 2) °C and (50 ± 6) % relative humidity (RH). After initial conditions, the joints exposed to the following aging test: The samples were completely wrapped with cotton. Then the wrapped samples were wetted evenly with demineralized water. The sample were wrapped completely in aluminum foil before placing in a polyethylene bag. Subsequently, the air taken out from the bag by hand and the polyethylene bag sealed airtight. The package sample is stored at (70 ± 2) °C and (100 – 6) %RH for 168 hours (7 days) and immediately exposed to (-20 ± 2) °C for 16 hours. Thereafter, the sample were thawed at room temperature, the package removed and the test piece reconditioned for 2 hours at (23 ± 2) °C and (50 ± 6) %RH.

[0088] For each strip containing the adhesive composition, the stress at break for the strips was determined from tensile tests which were performed with a Zwick type Z020 tensile tester equipped with a 1 kN load cell. The tests were performed on film strips with dimensions of 40 mm (length) x 5 mm (height) x 0.05 mm (width). A grip-to-grip separation of 20 mm was used. The samples were pre-stressed to 0.1 N and then loaded with a constant crosshead speed of 500 mm^min-1.

[0089] The results from the above tests are reported below - Table 2. Adhesion performance of ethylene polymer (RT- Room Temperature) CE1 CE2 CE3 Sample No. IE1 (P12) IE2 (P17) IE3 (P18) (P14) (P20) (LD) MFI2(dg / min) 13 8.3 25 25.3 52.5 2223POLY0061-WO-ORD 30 Total amount of polymeric units derived from the 6.0 10.0 10.5 2.8 6.1 0 cationic and anionic monomer IPC (wt.%) Value of MFI2 / IPC 2.17 0.83 2.38 9.03 8.61 NA Stress @break (Mpa) 136 172 14013193 33Adhesion to RT 7.2 >8.2 7 6 6.8 3 Aluminum substrate RTage 7.9 >8.2 >8 7.2 7.9 - based on lap 80oC 4.1 5 3.4 2.4 2.5 0.8 shear test (MPa) 100oC 1.4 1 0.5 0.6 0.3 0.2 Adhesion to RT 9.9 11.8 9 9.6 9.9 0.8 Steel substrate 80oC 5.0 3.5 2.8 2.6 3.1 0.8 based on lap shear test 100oC 1.3 1.1 0.7 0.6 0.2 0.6 (MPa) Adhesion to PP substrate based on lap RT 1.3 2.5 1.6 2 1.9 0 shear test (MPa) Adhesion to combination RT - 3.0 - 2.2 2.2 0.1 of Aluminum23POLY0061-WO-ORD 31 substrate and a PP (MPa)

[0090] For each of the strips IE1, IE2 and IE3 containing the adhesive composition in accordance with the present invention, the stress at break was much higher than that of the comparative example – indicative of the fact that these strips can be used as adhesive layers in preparing multi-layer articles and imparting the desired mechanical integrity to such articles when used as adhesive layers.

[0091] From the results as shown in Table 2, it is also evident that the even though all the adhesive composition, both inventive as well as comparative samples, contained the ethylene polymer derived from methacrylic acid and 2-(dimethylamino)ethyl methacrylate, the purposeful selection of ethylene polymers having a specific combination of melt flow index and IPC content, provided the desired adhesive strength to metal surfaces.

[0092] For example, sample IE2 at room temperature as well as at elevated temperature or even after aging, showed excellent adhesive strength compared to the adhesion strength of the sample CE1 and CE2, to both aluminum and steel. This is particularly surprising even though all the samples (IE2, CE1 and CE2) were based on an ethylene ionomers. The adhesion property of samples IE1-IE3 containing the ethylene polymer in accordance with the present invention, showed significantly improved adhesion performance over that of samples CE3, which was an adhesive composition derived from ordinary LDPE. Further, for the sample IE1 and IE2, adhesion to aluminum showed particularly improved from that of the comparative samples.

[0093] With regard to the polypropylene adhesion, the adhesion strength demonstrated by the inventive sample were sufficient to provide the necessary mechanical integrity while being comparable to the comparative samples- indicative of the fact that the plastic substrates can be dismantled from each other during recycling.

Claims

23POLY0061-WO-ORD 32 1. An adhesive composition, comprising > 90.0 wt.%, preferably ≥ 95.0 wt.%, of an ethylene polymer with regard to the total weight of the adhesive composition, wherein the ethylene polymer comprises or consists of: (a) polymeric units derived from ethylene; and (b) polymeric units derived from a cationic monomer represented by formula (I) ^hydrogen or an alkyl group having 1-10 carbon atoms, preferably 1-5 carbon atoms; ^ ‘X’ is independently selected from ‘O’ or ‘NH’, preferably ‘X’ is ‘O’; ^ R2 is an alkyl group having 1-40 carbon atoms, preferably 1-5 carbon atoms; ^ R3and R4are each independently selected from hydrogen or an alkyl group having 1-10 carbon atoms, preferably 1-5 carbon atoms; and ^ R5 is independently selected from hydrogen or an alkyl group having 1-20 carbon atoms, preferably 1-5 carbon atoms, ^ preferably wherein each of R3 and R4 is an alkyl group having 1-5 carbon atoms and R5 is hydrogen; and (c) polymeric units derived from at least one anionic monomer selected from the formula below,23POLY0061-WO-ORD 33 ^ wherefrom hydrogen or an alkyl group having 1-10 carbon atoms; ^ R8and R10are each independently selected from alkyl group having 1-40 carbon atoms; ^ ‘Y’, ‘V’ and ‘W’ is independently selected from ‘O’ or ‘NH’; ‘n’ is a number ranging from 1 to 20; ‘Z’ is independently selected from -SO3or -C(O)O; ^ preferably wherein the anionic monomer is alkyl group having 1-5 carbon atoms, and23POLY0061-WO-ORD 34 ^ the cationic monomer is where ‘X’ is ‘O’, and eachof R2, R3and R4is an and R5is hydrogen; (i) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 1.0 and ≤ 30.0 wt.%, preferably ≥ 1.5 and ≤ 20.0 wt.%, preferably ≥ 3.0 and ≤ 15.0 wt.%, preferably ≥ 3.0 and ≤ 14.0 wt.%, preferably ≥ 6.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (ii) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 0.1 and ≤ 100 dg / min, preferably ≥ 0.45 and ≤ 40.0 dg / min, preferably ≥ 1.0 and ≤ 30.0 dg / min, preferably ≥ 5.0 and ≤ 30.0 dg / min, preferably ≥ 5.0 and ≤ 25.0 dg / min, preferably ≥ 5.0 and ≤ 15.0 dg / min, preferably ≥ 5.0 and ≤ 14.0 dg / min, preferably ≥ 5.0 and ≤ 10.0 dg / min where MFI2is the melt flow index determined in accordance with ISO1133- 1:2011 at 190 ºC and measured at 2.16 kg; and (iii) wherein the value of MFI2 / IPC is > 0 and ≤ 3.3, preferably > 0 and ≤ 3.0, preferably > 0 and ≤ 2.5, preferably > 0 and ≤ 1.5, preferably ≥ 0.2 and ≤ 1.5, preferably > 0.5 and ≤ 1.0, where IPC and MFI2 are as defined herein.

2. The adhesive composition according to claim 1, (a) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 15.0 dg / min, preferably ≥ 5.0 and ≤ 14.0 dg / min; and (b) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 3.0 and ≤ 15.0 wt.%, preferably ≥ 6.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (c) wherein the value of MFI2 / IPC is > 0 and ≤ 2.0, preferably ≥ 0 and ≤ 1.5, preferably > 0 and ≤ 1.0, preferably ≥ 0.3 and ≤ 1.0, preferably > 0.5 and ≤ 1.0, where IPC and MFI2are as defined herein.23POLY0061-WO-ORD 35 3. The adhesive composition according to any one of claims 1-2, (a) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 14.0 dg / min, preferably ≥ 5.0 and ≤ 10.0 dg / min; and (b) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 6.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (c) wherein the value of MFI2 / IPC is > 0 and ≤ 1.0, preferably ≥ 0.3 and ≤ 1.0, preferably > 0.5 and ≤ 1.0, where IPC and MFI2 are as defined herein.

4. The adhesive composition according to any one of claims 1-3, wherein the anionic monomer is (II) where R6 is an alkyl group having 1-5 carbon atoms, andthe cationic monomer is where ‘X’ is ‘O’, and eachof R2, R3and R4is an R5is hydrogen, (a) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 10.0 dg / min; and (b) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 6.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (c) wherein the value of MFI2 / IPC is > 0 and ≤ 1.0, preferably ≥ 0.3 and ≤ 1.0, preferably > 0.5 and ≤ 1.0, where IPC and MFI2 are as defined herein.23POLY0061-WO-ORD 36 5. The adhesive composition any one of claims 1-4, wherein the cationic monomer represented by formula (I) is derived from the quaternarized form of a free base selected from the group consisting of: 2-(dimethylamino)ethyl acrylate, 2-(diethylamino)ethyl acrylate, 2-(diethylamino)ethyl methacrylate, 2-(dimethylamino)ethyl methacrylate, 2-(tert-butylamino)ethyl methacrylate, N-[3-(hexahydro-1 H-azepin-1 -yl)-1,1-dimethylpropyl]-2-propenamide, N-[2-(tetrahydro-1 ,4-oxazepin-4(5H)-yl)ethyl]- 2-propenamide, N-[2-[methyl(tetrahydro-2H-pyran-4-yl)amino]ethyl]- 2-propenamide, N-[3-(hexahydro-4-methyl-1 H-1 ,4-diazepin-1 -yl)propyl]- 2-propenamide, N-[1 -methyl-2-(methylamino)propyl]- 2-propenamide, N-[2-(methylamino)propyl]- 2-propenamide, N-[2-methyl-2-(methylamino)propyl]- 2-propenamide, N-[1 -methyl-2-(methylamino)ethyl]- 2-propenamide, N-[1 -methyl-3-(methylamino)butyl]- 2-propenamide, and N-[1 -methyl-2-(methylamino)propyl]- 2-propenamide, preferably wherein the cationic monomer of formula (I) is derived from the quaternarized form of the free base selected from the group consisting of 2-(dimethylamino)ethyl acrylate, 2-(diethylamino)ethyl acrylate, 2-(diethylamino)ethyl methacrylate, 2- (dimethylamino)ethyl methacrylate, and 2-(tert-butylamino)ethyl methacrylate.

6. The adhesive composition according to any one of claims 1-5, wherein the anionic monomer is derived from the deprotonated form of a free acid selected from the group consisting of: acrylic acid, methacrylic acid, 2-methyl-2-[(1 -oxo-2-propen-1 -yl)amino]- 1 -propanesulfonic acid, 2-methyl-1 -[(1 -oxo-2-propen-1 -yl)amino]- 1 -propanesulfonic acid,23POLY0061-WO-ORD 37 1 -[(1 -oxo-2-propen-1 -yl)amino]- acid 2-[(2-methyl-1 -oxo-2-propen-1 -yl)amino]-2-propanesulfonic acid, 1 -[(1 -oxo-2-propen-1 -yl)amino]-ethanesulfonic acid, 2-(phosphonooxy)ethylester-2-propenoic acid, 2-propenoic acid, 2-methyl-, 2-(phosphonooxy)ethyl ester, 2-methyl-, 1 -methyl-3-(phosphonooxy)propyl ester-2-propenoic acid, 2-methyl-, 1 -[(phosphonooxy)methyl]propyl ester-2-propenoic acid, 2-methyl-N-[7-(phosphonooxy)heptyl]- 2-propenamide, 4-(phosphonooxy)butyl ester-2-propenoic acid, 2-methyl-, 12-(phosphonooxy)dodecyl ester-2-propenoic acid, 2-methyl-, 10-(phosphonooxy)decyl ester-2-propenoic acid, 2-methyl-, 6-(phosphonooxy)hexyl ester-2-propenoic acid, 2-methyl-, 3-(phosphonooxy)propyl ester-2-propenoic acid, 2-methyl-, 1 -methyl-2-(phosphonooxy)ethyl ester-2-propenoic acid, 3-(phosphonooxy)propyl ester-2-propenoic acid, 2-methyl-, 4-(phosphonooxy)butyl ester-2-propenoic acid, 2-oxo-2-[[[(1 -oxo-2-propen-1 -yl)amino]methyl]amino]-ethanesulfonic acid, and 2-[[[(2-methyl-1 -oxo-2-propen-1 -yl)amino]methyl]amino]-2-oxo-ethanesulfonic acid; preferably wherein the anionic monomer is derived from the deprotonated form of any one of acrylic acid, or methacrylic acid.

7. The adhesive composition according to any one of claims 1-6, wherein the anionic monomer is derived from the deprotonated form of any one of acrylic acid, or methacrylic acid; and wherein the cationic monomer is derived from the quaternarized form of the free base selected from the group consisting of 2-(dimethylamino)ethyl acrylate, 2- (diethylamino)ethyl acrylate, 2-(diethylamino)ethyl methacrylate, 2- (dimethylamino)ethyl methacrylate, and 2-(tert-butylamino)ethyl methacrylate.23POLY0061-WO-ORD 38 8. The adhesive composition any one of claims 1-7, wherein the cationic monomer is derived from the quaternarized form of 2-(dimethylamino)ethyl methacrylate and the anionic monomer is derived from the deprotonated form of methacrylic acid.

9. The adhesive composition according to any one of claims 1-8, wherein the cationic monomer is derived from the quaternarized form of 2-(dimethylamino)ethyl methacrylate and the anionic monomer is derived from the deprotonated form of methacrylic acid; (a) wherein the melt flow index (MFI2) of the ethylene polymer ranges from ≥ 5.0 and ≤ 10.0 dg / min; and (b) wherein the total content of polymeric units derived from the cationic monomer and the anionic monomer (IPC) ranges from ≥ 6.0 and ≤ 12.0 wt.%, with regard to the total weight of the ethylene polymer; and (c) wherein the value of MFI2 / IPC is > 0.5 and < 1.0, where IPC and MFI2 are as defined herein.

10. A process of preparing the adhesive composition according to any one of claims 1-9, wherein the process comprises the step of polymerizing in a high pressure reactor, ethylene with the cationic monomer represented by formula (I) and with the one or more anionic monomer represented by formula (II), (III), (IV) and (V) to obtain the ethylene polymer and optionally mixing the ethylene polymer and additives to obtain the adhesive composition; and wherein the polymerization is carried out in a high pressure reactor: ^ at a temperature of ≥ 150 ºC and ≤ 310 ºC, preferably ≥ 170 ºC and ≤ 290 ºC, preferably ≥ 170 ºC and ≤ 220 ºC, preferably ≥ 170 ºC and ≤ 210 ºC; and ^ at a pressure of ≥ 180 MPa and ≤ 350 MPa, preferably ≥ 190 MPa and ≤ 310 MPa, preferably ≥ 190 MPa and ≤ 310 MPa, preferably ≥ 200 MPa and ≤ 300 MPa; and ^ in presence of one or more free-radical initiator present in an amount of ≥ 0.3 milli mol.% and ≤ 1.1 milli mol.%, with regard to total amount of ethylene monomer in the high pressure reactor; and23POLY0061-WO-ORD 39 ^ optionally in presence of or more chain transfer agent (CTA) present in an amount of > 0.01 and < 0.1 mol%, preferably ≥ 0.05 and ≤ 0.1 mol%, with regard to total amount of ethylene monomer in the high pressure reactor.

11. An article comprising a substrate layer and an adhesive layer in contact with at least a portion of the substrate layer, wherein the adhesive layer comprises ≥ 95.0 wt.% with regard to the total weight of the adhesive layer, of the adhesive composition according to any one of claims 1-9, preferably the article is a multi-layer article comprising a first substrate layer, a second substrate layer and an adhesive layer comprising ≥ 95.0 wt.% with regard to the total weight of the adhesive layer, of the adhesive composition according to any one of claims 1-9, wherein adhesive layer is in contact with at least a portion of the first substrate layer and at least a portion of the second substrate layer and wherein the adhesive layer is positioned between the first substrate layer and the second substrate layer.

12. The article according to claim 11, wherein the article is a multi-layered article and wherein the first substrate layer is identical or different from the second substrate layer and wherein first substrate layer and / or second layer is a selected from any one of metal, glass, ceramic or plastic.

13. The article according to any one claims 11-12, wherein the article is a multi-layered article and wherein the first substrate layer and / or second layer is a plastic selected from polypropylene, polyethylene, polystyrene, polycarbonate, polyvinylchloride, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyphenylene sulfide, polyvinyl alcohol, polyester, polyether, polyvinyl acetate, polyethylene glycol, polyvinylidene fluoride, polytetrafluoroethylene, styrene butadiene rubber, polyisoprene, chloroprene rubber, acrylic rubber, polymer having cyano group, urethane rubber, ethylene propylene rubber, epichlorohydrin rubber, butadiene rubber, fluorine rubber, acrylic-vinyl alcohol copolymer, epoxy resin, oxetane resin, urethane resin, acrylic resin, polysaccharide, polyimide, polyamideimide, silicone, cellulose based or a combination23POLY0061-WO-ORD 40 thereof, preferably wherein the first layer and / or second layer is a plastic selected from any one of polypropylene or polyethylene.

14. The article according to any one claims 11-12, wherein the article is a multi-layered article and wherein the first substrate layer and / or second substrate layer is a metal selected from Iron, Aluminum, Cobalt, Nickel, Copper, Zinc, Tungsten, Tin, Gold, Silver, Magnesium, Titanium, steel, metal alloy and combination thereof, preferably wherein the first substrate layer and / or second layer is a metal selected from any one of aluminum, or steel, preferably, wherein the first substrate layer and / or second layer is aluminum; preferably wherein the article is an extrusion coated article, a film, an automobile component, a high pressure pipe, a moulded article, a 3D printed article, a metal article or a polymer alloy and combinations thereof.

15. Use of the ethylene polymer defined in any one of claims 1-9 for making an adhesive composition.

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