Laminated structure

Abstract

The invention relates to a laminate (1) comprising an adhesive layer (5) made of a one-component adhesive composition wherein the functional groups of the one-component consist of isocyanate moieties and the composition does not contain any polyurethane having a weight average molecular weight of 20000 g / mol or more. The invention also relates to a laminate comprising an adhesive layer (5) made of a one-component adhesive composition applied at a dry coating weight of less than 1 g / m2. The invention also relates to a laminate comprising an adhesive layer (5) made of a one-component adhesive composition which is curable under moisture-free conditions. The invention also relates to a laminate comprising an adhesive layer (5) made of a one-component adhesive composition having a concentration of isocyanate groups in the range of 0.5 to 10%.

Description

[0001] The present invention relates to a laminate structure comprising an adhesive layer based on a one-component adhesive composition.

[0002] Laminates are common structures and are used in various technical fields, such as in flexible packaging.

[0003] The term "laminate" means a product composed of a stack of layers, wherein one layer (outermost or core layer) is defined as a substrate or substrate layer. On said substrate or substrate layer, at least one layer, preferably a stack of layers, is provided, wherein said layer or stack of layers is typically or comprises a print layer or several print layers. Typically, a further substrate or substrate layer is applied on the distal side of said layer or stack of layers, so that the layer or stack of layers is sandwiched between these substrate layers and is protected from the environment.

[0004] In such laminates, one or more print layers are typically connected to the substrate layer via a primer layer and / or an adhesive layer. Such primer layer and / or adhesive layer in a laminate has to fulfill specific requirements regarding adhesion, reduced brittleness (i.e. increased flexibility), and has to achieve, inter alia, high bond strength values.

[0005] An adhesive layer is prepared from an adhesive composition. Adhesive compositions are typically used to bond together various substrates, for example plastic substrates such as polyethylene, polypropylene, polyester or polyamide, or other kinds of substrates such as metal or paper.

[0006] The use of adhesives in different laminate end-use applications is generally known. For example, adhesives can be used for the manufacture of film / film and film / foil laminates used in the flexible packaging industry, in particular for food packaging.

[0007] For example, a first laminate structure can be formed by applying one or more print ink layers onto a first substrate, preferably by means of a primer layer which is applied first onto said first substrate, followed by the application of one or more print ink layers onto the primer layer. An adhesive layer can then be applied onto the free surface of a second substrate, and the laminate structure can then be joined using conventional lamination methods using a conventional laminator.

[0008] Adhesive compositions for laminate applications are generally known. They can be solvent-borne, water-borne or solvent-free.

[0009] Generally known solvent-borne adhesive compositions for laminate applications comprise polyurethanes. For laminate applications, typically two-component polyurethane-based adhesive compositions are used, which comprise a first component comprising isocyanate and / or a polyurethane prepolymer containing free isocyanate groups, and a second component comprising one or more polyols, such as polyether polyols or polyester polyols.

[0010] The two components of the adhesive composition are formulated separately in common organic solvents such as methyl ethyl ketone, ethyl acetate or toluene, optionally together with one or more additives commonly used in adhesive compositions.

[0011] For use, the two components are mixed in a predetermined ratio, thereby forming the adhesive composition, which is then applied to the desired substrate surface. The other surface is brought into contact with the applied adhesive composition, and after curing of the adhesive composition, the desired laminate structure is formed.

[0012] An example of a suitable adhesive is a typical solvent borne 2K adhesive like Adcote 811 A, preferably in combination with a typical hardener like 9L10 (both raw materials are commercially available from DOW).

[0013] Such two-component adhesive compositions have several disadvantages. The two components must be stored separately to prevent their premature reaction, which would lead to premature curing. This doubles the required storage equipment. Furthermore, it also leads to an increase in raw material costs due to the necessity to use two components.

[0014] When used, the two components must be mixed with each other in the correct ratio. This must be done on site at the manufacturer and is a source of possible dosage errors. Furthermore, it can happen that unused amounts of components can be left over and (due to their limited shelf life) must be disposed of as waste, possibly due to production problems, for example.

[0015] Finally, the cleaning of the equipment required for curing two-component adhesive compositions can be cumbersome.

[0016] While one-component adhesive compositions are known per se, they are not considered suitable for laminate applications.

[0017] In WO 2020 / 117399 A1 it is suggested to use a laminate adhesive composition which is designated as a general one-component adhesive having predominantly isocyanate groups. As an example, the commercial adhesive Adcote 811 A is mentioned. TM 331. Adcote 811 A is an isocyanate-terminated polyether urethane adhesive, i.e. an isocyanate-terminated polyurethane adhesive. According to WO 2020 / 117399 A1, Adcote 811 A contains predominantly isocyanate groups. Further details about Adcote 811 A are unknown. TM 331. Adcote 811 A is an isocyanate-terminated polyether urethane adhesive, i.e. an isocyanate-terminated polyurethane adhesive. According to WO 2020 / 117399 A1, Adcote 811 A contains predominantly isocyanate groups. Further details about Adcote 811 A are unknown. TM 331 contains predominantly isocyanate groups. Further details about Adcote 811 A are unknown. TM 331 contains predominantly isocyanate groups. Further details about Adcote 811 A are unknown.

[0018] WO 2020 / 117399 A1 explicitly discloses the use of the one-component adhesive of the present invention in combination with a functionalized film layer, wherein at least one functionalized film layer comprises a polar-reactive group polyolefin layer. In WO 2020 / 117399 A1, only grafted polyolefin layers are explicitly tested as polar-reactive group polyolefin layers.

[0019] In the examples of WO2020 / 117399A1, it is shown that the corona-treated LLDPE copolymer substrate is suitable for the one-component adhesive Adcote TM The teaching of WO 2020 / 117399 A1 is limited to the use of a one-component isocyanate-terminated polyurethane adhesive in combination with a polyolefin layer functionalized by grafting. Other substrate layers, such as corona-treated substrates, were found to result in insufficient properties of the laminate.

[0020] The problem underlying the present invention is to provide a laminate for packaging applications which overcomes the problems associated with the use of two-component adhesive compositions in the manufacture of said substrates.

[0021] The present invention solves the above-mentioned problems.

[0022] In detail, according to a first aspect, the present invention relates to a laminate for packaging applications, comprising a substrate layer and an adhesive layer present on a surface of the substrate layer, characterized in that the adhesive layer is made of a one-component adhesive composition, wherein the functional groups of the one-component consist of isocyanate moieties and the composition does not contain any polyurethane, the polyurethane having a weight average molecular weight of 20,000 g / mol or more, preferably 15,000 g / mol or more, more preferably 10,000 g / mol or more, even more preferably 5,000 g / mol or more, preferably 2,500 g / mol or more, and most preferably 1,000 g / mol or more.

[0023] Unless otherwise indicated, any weight average molecular weight is determined by GPC (gel permeation chromatography) using polystyrene as a standard.

[0024] It has been found that the disclosed one-component adhesive compositions, wherein the functionality of the one-component consists of isocyanate moieties, can be used in lamination applications in combination with substrates that have not been grafted with any polar component but have only been corona treated or even untreated.

[0025] According to a preferred embodiment, the one-component adhesive composition has an isocyanate group concentration of 0.5 to 10%, preferably 1 to 9%, more preferably 2 to 8%, and particularly preferably 3 to 7%, based on the weight of the total amount of the composition.

[0026] According to the present application, the concentration of isocyanate groups is the amount of isocyanate groups in the composition based on the weight of the total amount of the composition.

[0027] The present application provides a solution which is widely applicable for lamination and overcomes the disadvantages associated with two-component adhesive compositions. There is no mixing error as the individual components do not need to be mixed at the manufacturer's site. There is no problem with any remaining components as there is no mixing of individual components which can result in any remaining unused raw materials. Furthermore, the limited pot life of 2K-adhesive systems caused by the increasing viscosity and decreasing bond strength values during processing due to the reaction of the two components is not a problem for the 1 K-adhesive system as no reaction between the two components occurs. Thus, waste is reduced or avoided. There is no need to provide mixing equipment for mixing the individual components of a two-component adhesive composition, thereby reducing costs and cleaning time. Raw material costs and storage costs can be reduced.

[0028] Furthermore, in the one-component adhesive composition of the present application, there is no polyhydroxy polyol component. This leads to a reduction of the dry coat weight of the adhesive layer made from the one-component adhesive composition according to the present application. Thus, the laminate comprising the adhesive layer made from the one-component adhesive composition according to the present application also has a higher content of recyclable material (percentage of polymer in the packaging structure), which improves the overall recyclability of the laminate, and accordingly the overall recyclability of the flexible package made from said laminate.

[0029] According to a preferred embodiment, the adhesive layer (5) is applied with a dry coat weight of less than 1 g / m2 2 , preferably 0.1 to 0.9 g / m2 2 , more preferably 0.2 to 0.8 g / m2 2 , and especially preferably 0.3 to 0.7 g / m2 2 . The dry coat weight can be determined by known methods, for example based on the amount of adhesive composition used, or by weighing the uncoated article and the dried coated article (i.e. the article to which the adhesive layer is applied), and determining the dry coat weight as the difference between these two weights.

[0030] Compared to conventional two-component adhesive compositions, the one-component adhesive composition according to the present application has lower formulation complexity due to its simpler composition, and also has more robust application properties.

[0031] In particular, it has been found that the use of the one-component adhesive composition according to the present application can result in higher bond strength values at lower dry coat weights compared to conventional two-component adhesive compositions.

[0032] Furthermore, a faster curing is observed using the one-component adhesive composition according to the present application compared to conventional two-component adhesive compositions.

[0033] Preferably, the one-component adhesive composition is curable under moisture-free conditions. By "curable under moisture-free conditions" it is understood that the one-component adhesive composition according to the present application does not require any water for curing. It is not necessary to add any water to the composition for curing or to provide a higher defined air humidity during the process. Furthermore, the one-component adhesive composition according to the present application is curable under very dry conditions of less than 20% RH (relative humidity, preferably less than 10% RH, more preferably less than 5% RH).

[0034] Using the one-component adhesive composition according to the present application, also a very good stability under retort conditions (as usually used for sterilization purposes) is observed.

[0035] The one-component adhesive composition according to the present application is solvent- borne. Thus, the composition comprises at least one organic solvent. Any organic solvent conventionally used in adhesive compositions can be used. Examples are esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, neopentyl acetate, acetone or MEK (methyl ethyl ketone). The one-component adhesive composition according to the present application can also comprise a mixture of any of the above-mentioned organic solvents. Preferably, the one-component adhesive composition according to the present application comprises 10 to 80 wt.-%, more preferably 20 to 70 wt.-%, and particularly preferably 30 to 65 wt.-% of the at least one solvent, based on the weight of the entire adhesive composition.

[0036] The one-component adhesive composition according to the present application this aspect is so constituted that the functional group of the one-component consists of isocyanate moieties. In other words, the one-component does not have any other functional group than isocyanate moieties. By "functional group" it is meant a chemical group which contributes to the curing reaction to obtain an adhesive layer from the one-component adhesive composition. Such functional group is a free (i.e. unreacted) functional group and does not contain internal groups such as ether, ester or carbamate groups derived from the reaction of starting materials such as from two alcohols, an alcohol and an acid, or an alcohol and an isocyanate.

[0037] The one-component adhesive composition according to the present application comprises an isocyanate component, which comprises at least two free isocyanate moieties. The isocyanate component can be a polyisocyanate (i.e. an isocyanate having more than one unreacted isocyanate moiety) or an isocyanate oligomer.

[0038] The isocyanate component can be selected from aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and combinations of two or more thereof. "Aromatic polyisocyanates" are polyisocyanates containing one or more aromatic rings. "Aliphatic polyisocyanates" do not contain aromatic rings. "Alicyclic polyisocyanates" are aliphatic polyisocyanates containing at least one aliphatic ring structure.

[0039] Suitable aromatic polyisocyanates contain 3 to 16 carbon atoms, more preferably 4 to 12 carbon atoms, and 2 to 5, preferably 2 to 4, free, unreacted isocyanate moieties. Preferred polyisocyanates include, but are not limited to, 1,3-phenylene diisocyanate and 1,4-phenylene diisocyanate, 1,5-naphthylene diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate (2,4-TDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 3,3'-dimethyl-4,4'-biphenyl diisocyanate (TODI), polymeric isocyanates, and combinations of two or more thereof.

[0040] Suitable aliphatic polyisocyanates can be straight or branched chain aliphatic hydrocarbons having from 3 to 16 carbon atoms, more preferably from 4 to 12 carbon atoms in the alkylene residue and from 2 to 5, preferably 2 to 4 free, unreacted isocyanate moieties.

[0041] Suitable cycloaliphatic polyisocyanates advantageously have from 4 to 18 carbon atoms, more preferably from 4 to 12 carbon atoms, and from 2 to 5, preferably 2 to 4, free, unreacted isocyanate moieties.

[0042] Examples of suitable aliphatic and cycloaliphatic polyisocyanates include, but are not limited to, cyclohexane diisocyanate, methylcyclohexane diisocyanate, ethylcyclohexane diisocyanate, propylcyclohexane diisocyanate, methyldiethylcyclohexane diisocyanate, propane diisocyanate, butane diisocyanate, pentane diisocyanate, hexane diisocyanate, heptane diisocyanate, octane diisocyanate, nonane diisocyanate, nonane triisocyanate, such as 4-isocyanatomethyl-1,8-octane diisocyanate (TIN), decane diisocyanate and decane triisocyanate, undecane diisocyanate and undecane triisocyanate and dodecane diisocyanate and dodecane triisocyanate, isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), diisocyanatodicyclohexylmethane (H12g MDI), 2-methylpentane diisocyanate (MPDI), 2,2,4-trimethylhexamethylene diisocyanate / 2,4,4-trimethylhexamethylene diisocyanate (TMDI), norbornane diisocyanate (NBDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate, and dimers, trimers (isocyanurate), such as trimers of hexane-1,6 diisocyanate, and mixtures of the above.

[0043] According to a preferred embodiment of the present application, the isocyanate component can also be a compound derived from the reaction of one or more of the above polyisocyanates with a compound having isocyanate-reactive functionality. For example, a mono- or polyhydroxy compound (containing only one or more than one reactive OH group) can be reacted with one or more of the above polyisocyanates to give a urethane. As an example, one can mention the reaction product of ethylene glycol, propylene glycol, neopentyl glycol or trimethylolpropane with, for example, an aliphatic diisocyanate such as hexane-1,6-diisocyanate or an aromatic diisocyanate such as toluene-2,4-diisocyanate. A preferred urethane is the reaction product of trimethylolpropane with toluene-2,4-diisocyanate, wherein all three OH groups of the trimethylolpropane are reacted with toluene-2,4-diisocyanate:

[0044]

[0045] Although this compound contains three urethane moieties, it is not a urethane oligomer or polyurethane, as it is not composed of any repeating units.

[0046] Likewise, a mono- or polyamine compound, or a mono- or polythiol compound, can be reacted with one or more of the above polyisocyanates, which will result in a urea compound or a thiourethane compound.

[0047] According to a preferred embodiment of the present invention, the isocyanate component can also be an oligomer. Oligomers can be obtained by reacting one or more of the above-mentioned polyisocyanates with a compound having at least two isocyanate-reactive functional groups, resulting in multiple repeating units. Such oligomers must contain at least two free isocyanate (NCO) groups. As an example, the reaction of ethylene glycol and hexane-1,6-diisocyanate under such conditions yields an oligomer of the formula:

[0048]

[0049] An oligomer is generally defined as having a small number of repeating units (e.g., in the above formula, n is small), while a polymer is generally defined as having a large number of repeating units (e.g., in the above formula, n is large). However, there is no clear distinction between oligomers and polymers. According to the present invention, an oligomer is defined as having a weight-average molecular weight (Mw) of less than 5000 g / mol.

[0050] The one-component adhesive composition according to the present invention may also contain a combination of the above-mentioned isocyanate components, wherein the isocyanate component contains at least two free isocyanate moieties. Preferably, the one-component adhesive composition according to the present invention contains 90% to 20% by weight, more preferably 80% to 30% by weight, and particularly preferably 30% to 65% by weight of the at least one isocyanate component containing at least two free isocyanate moieties, based on the weight of the entire adhesive composition.

[0051] However, it is important that the composition does not contain any polyurethane having a weight average molecular weight of 20,000 g / mol or more, preferably 15,000 g / mol or more, more preferably 10,000 g / mol or more, even more preferably 5,000 g / mol or more, preferably 2,500 g / mol or more, and most preferably 1,000 g / mol or more.

[0052] Polyurethanes are defined as polymers derived from the reaction of one or more of the above-mentioned polyisocyanates with a compound having at least two isocyanate-reactive hydroxyl groups, resulting in a plurality of repeating units comprising urethane groups. For example, in the formula shown above and reproduced again below, the repeating units (in brackets) comprise urethane groups, and n is set so that the compound has a weight-average molecular weight (Mw) of at least 5000 g / mol:

[0053]

[0054] The one-component adhesive composition according to the present application can additionally comprise one or more additives which are commonly used in adhesive compositions. Examples of such additives include, but are not limited to, tackifiers, plasticizers, rheology modifiers, adhesion promoters, antioxidants, fillers, colorants, surfactants, catalysts, and combinations of two or more thereof. Preferably, the one-component adhesive composition according to the present application comprises 0 to 5 wt.%, more preferably 0.1 to 4 wt.%, particularly preferably 0.5 to 3 wt.% of at least one additive, based on the weight of the entire adhesive composition.

[0055] The one-component adhesive composition according to the present application can be prepared by conventional mixing methods such as mixing the above-mentioned ingredients using a stirrer. Depending on the isocyanate present in the composition, the preparation of the one-component adhesive composition according to the present application can be carried out under inert gas atmosphere, for example under nitrogen.

[0056] According to this aspect, the present application also comprises a method of preparing a laminate, which comprises the step of applying the above-mentioned one-component adhesive composition to the free surface of a substrate layer in a dry coating weight of less than 1 g / m2, 2 , preferably 0.1 to 0.9 g / m2, 2 , more preferably 0.2 to 0.8 g / m2, 2 , especially preferably 0.3 to 0.7 g / m2, 2 , and preferably under conditions free of moisture.

[0057] According to the second aspect, the present application relates to a laminate for packaging applications, which comprises a substrate layer and an adhesive layer present on the surface of said substrate layer, characterized in that the adhesive layer is made of a one-component adhesive composition and is applied in a dry coating weight of less than 1 g / m2, 2 , preferably 0.1 to 0.9 g / m2, 2 , more preferably 0.2 to 0.8 g / m2, 2 , especially preferably 0.3 to 0.7 g / m2, 2 . The dry coating weight can be determined by known methods, for example based on the amount of adhesive composition used, or by weighing the uncoated article and the dried coated article, i.e. the article to which the adhesive layer is applied, and determining the dry coating weight as the difference between these two weights.

[0058] It has been found that according to the present application, an adhesive layer with satisfactory adhesive function can be provided even when the adhesive layer is applied in a low dry coating weight. Preferably, the laminate application of such a low dry coating weight of the adhesive layer can also be combined with a substrate which is not grafted with any polar component, but is only corona treated or even untreated.

[0059] According to a preferred embodiment of this aspect, this can be achieved by using a one-component adhesive composition, wherein the functional groups of the one-component adhesive composition consist of isocyanate moieties and the composition does not comprise any polyurethane having a weight average molecular weight of 20000 g / mol or more, preferably 15000 g / mol or more, more preferably 10000 g / mol or more, even more preferably 5000 g / mol or more, particularly preferably 2500 g / mol or more, and most preferably 1000 g / mol or more.

[0060] According to a preferred embodiment of this aspect, the concentration of isocyanate groups of the one-component adhesive composition is from 0.5 to 10 %, preferably from 1 to 9 %, more preferably from 2 to 8 %, and particularly preferably from 3 to 7 %, based on the weight of the total amount of the composition.

[0061] According to the present application of this aspect, the concentration of isocyanate groups is the amount of isocyanate groups in the composition, based on the weight of the total amount of the composition.

[0062] According to this aspect, the present application is not limited to the use of one-component adhesive compositions, wherein the functional groups of the one-component adhesive composition consist of isocyanate moieties. Other one-component adhesive compositions based on different functional groups can also be suitable. For example, compounds having reactive groups such as epoxy, silane, maleic anhydride, carbodiimide, and aziridine can be used.

[0063] As used herein, the term "epoxy" denotes a cyclic ether functional group, wherein an oxygen atom is attached to two adjacent carbon atoms. The term "compound having an epoxy group" is intended to encompass polyepoxide compounds (having two or more epoxy groups). Suitable epoxy compounds can be saturated or unsaturated, aliphatic, cycloaliphatic, aromatic, or heterocyclic and can be substituted. Furthermore, the epoxy compounds can also be monomeric, oligomeric, or polymeric.

[0064] Suitable polyepoxide compounds can be liquid, solid, or a solution in a solvent. Furthermore, such polyepoxide compounds should have an epoxy equivalent weight of from 100 to 700 g / eq, for example from 120 to 320 g / eq. According to the present application, diepoxide compounds having an epoxy equivalent weight of less than 500 g / eq or even less than 400 g / eq are preferred. Exemplary polyepoxide compounds can be glycidyl ethers of polyhydric alcohols and polyhydric phenols; glycidyl esters of polybasic carboxylic acids; and epoxidized polyethylenically unsaturated hydrocarbons, esters, ethers, and amides.

[0065] Suitable diglycidyl ether compounds can be aromatic, aliphatic or cycloaliphatic, such as diglycidyl ethers of aliphatic and cycloaliphatic diols such as 1,2-ethanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,12-dodecanediol, cyclopentanediol and cyclohexanediol; bisphenol A based diglycidyl ethers; bisphenol F diglycidyl ethers; polyalkylene glycol based diglycidyl ethers, in particular polypropylene glycol diglycidyl ethers; and polycarbonate diol based glycidyl ethers.

[0066] Exemplary polyepoxide compounds are glycerol polyglycidyl ethers; trimethylolpropane polyglycidyl ethers; pentaerythritol polyglycidyl ethers; diglycerol polyglycidyl ethers; polyglycerol polyglycidyl ethers; and sorbitol polyglycidyl ethers.

[0067] The term “compound having silane groups” is intended to encompass any compound containing silane groups, preferably silane-terminated polyethers, silane-terminated polyurethanes such as silanes based on aminoalkyl-functional, diisocyanates and polyethers, and polyesters, polyether and / or polyurethane prepolymers having at least two hydrolysable alkoxysilane groups, wherein the prepolymers have a molecular weight of 2000 to 30000 g / mol.

[0068] The term “compound having maleic anhydride groups” is intended to encompass oligomers and prepolymers having two or more maleic anhydride groups, preferably terminal maleic anhydride groups. For example, maleic anhydride-styrene polymers or alkyl vinyl ether-maleic anhydride type copolymers can be mentioned.

[0069] The term “compound having carbodiimide groups” is intended to encompass compounds containing two or more carbodiimide functional groups, such as CX-300 from Covestro.

[0070] The term “aziridinyl group” is intended to encompass a cyclic amino functional group in which a nitrogen atom is attached to two adjacent carbon atoms. The term “compound having aziridinyl groups” is intended to encompass polyaziridine compounds (having two or more aziridinyl groups). Suitable aziridine compounds can be saturated or unsaturated, aliphatic, cycloaliphatic, aromatic or heterocyclic, and can be substituted. Furthermore, aziridine compounds can also be monomeric, oligomeric or polymeric.

[0071] Preferred compounds include trimethylolpropane tri(3-aziridinyl propionate, trimethylolpropane tri(3-(2-methylaziridinyl) propionate), trimethylolpropane tri[2-aziridinyl butyrate], trimethylolpropane tri-[β-(N-aziridinyl) propionate], tris(1 -aziridinyl) phosphine oxide, tris(2-methyl-1 -aziridinyl) phosphine oxide, pentaerythritol tri[3-(1 -aziridinyl) propionate], pentaerythritol tri[β-(N-aziridinyl) propionate] and pentaerythritol tetra[3-(1 -aziridinyl) propionate].

[0072] The present application provides a solution which is widely applicable to laminating and overcomes the disadvantages associated with two-component adhesive compositions. There is no mixing error as the individual components do not need to be mixed at the site of the manufacturer. There is no problem with any remaining components as there is no mixing of individual components which can result in any remaining unused raw materials. Furthermore, the limited pot life of 2K-adhesive systems caused by the increasing viscosity and decreasing bond strength values during processing due to the reaction of the two components is not a problem for the 1 K-adhesive system as no reaction between the two components occurs. Thus, waste is reduced or avoided. There is no need to provide mixing equipment for mixing the individual components of a two-component adhesive composition, thereby reducing costs and cleaning time. Raw material costs and storage costs can be reduced.

[0073] Furthermore, in the one-component adhesive composition according to this aspect of the present application, there is no polyhydroxyl polyol component. This leads to a reduction of the dry coat weight of the adhesive layer made from the one-component adhesive composition according to the present application. Thus, the adhesive layer made from the one-component adhesive composition according to this aspect of the present application also has a higher content of recyclable material (percentage of polymer in the packaging structure) and improves the overall recyclability of the laminated material made therefrom, and accordingly the overall recyclability of the flexible package made from said laminated material.

[0074] The one-component adhesive composition according to this aspect of the present application has a lower formulation complexity due to its simpler composition and also has more robust application properties compared to conventional two-component adhesive compositions.

[0075] In particular, it has been found that the use of the one-component adhesive composition according to this aspect of the present application can result in higher bond strength values at lower dry coat weights compared to conventional two-component adhesive compositions.

[0076] Furthermore, the use of the one-component adhesive composition according to this aspect of the present application observes faster curing compared to conventional two-component adhesive compositions.

[0077] Preferably, the one-component adhesive composition is curable in the absence of moisture. "Curable in the absence of moisture" is understood to mean that the one-component adhesive composition according to the present invention does not require any water for curing. It is not necessary to add any water to the composition for curing, or to provide a higher defined humidity during the process. Furthermore, the one-component adhesive composition according to the present invention is curable under very dry conditions of less than 20% RH (relative humidity, preferably less than 10% RH, more preferably less than 5% RH).

[0078] Very good stability under retort conditions (as typically used for sterilization purposes) has also been observed with the one-component adhesive compositions according to this aspect of the invention.

[0079] The one-component adhesive composition according to this aspect of the present invention is solvent-based. Therefore, the composition contains at least one organic solvent. Any organic solvent conventionally used in adhesive compositions can be used. Examples include esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, neopentyl acetate, acetone, or MEK (methyl ethyl ketone). The one-component adhesive composition according to the present invention may also contain mixtures of any of the aforementioned organic solvents. Preferably, the one-component adhesive composition according to the present invention contains 10 to 80% by weight, more preferably 20 to 70% by weight, and particularly preferably 30 to 65% by weight of the at least one solvent, based on the weight of the entire adhesive composition.

[0080] The one-component adhesive composition according to this aspect of the invention is preferably constructed such that the functional groups of the one-component consist of an isocyanate moiety. In other words, in a preferred embodiment of this aspect of the invention, the one-component does not have any other functional groups other than the isocyanate moiety. "Functional group" refers to a chemical group that contributes to the curing reaction to obtain an adhesive layer from the one-component adhesive composition. Such functional groups are free (i.e., unreacted) functional groups and do not contain internal groups such as ether, ester, or urethane groups derived from the reaction of starting materials (such as two alcohols, an alcohol and an acid, or an alcohol and an isocyanate).

[0081] The one-component adhesive composition according to this aspect of the invention preferably comprises an isocyanate component comprising at least two free isocyanate moieties. The isocyanate component may be a polyisocyanate (i.e., an isocyanate having more than one unreacted isocyanate moiety) or an isocyanate oligomer.

[0082] The isocyanate component can be selected from aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and combinations of two or more thereof. "Aromatic polyisocyanates" are polyisocyanates containing one or more aromatic rings. "Aliphatic polyisocyanates" do not contain aromatic rings. "Alicyclic polyisocyanates" are aliphatic polyisocyanates containing at least one aliphatic ring structure.

[0083] Suitable aromatic polyisocyanates contain 3 to 16 carbon atoms, more preferably 4 to 12 carbon atoms, and 2 to 5, preferably 2 to 4, free, unreacted isocyanate moieties. Preferred polyisocyanates include, but are not limited to, 1,3-phenylene diisocyanate and 1,4-phenylene diisocyanate, 1,5-naphthylene diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate (2,4-TDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 3,3'-dimethyl-4,4'-biphenyl diisocyanate (TODI), polymeric isocyanates, and combinations of two or more thereof.

[0084] Suitable aliphatic polyisocyanates can be straight or branched chain aliphatic hydrocarbons having from 3 to 16 carbon atoms, more preferably from 4 to 12 carbon atoms in the alkylene residue and from 2 to 5, preferably 2 to 4 free, unreacted isocyanate moieties.

[0085] Suitable cycloaliphatic polyisocyanates advantageously have from 4 to 18 carbon atoms, more preferably from 4 to 12 carbon atoms, and from 2 to 5, preferably 2 to 4, free, unreacted isocyanate moieties.

[0086] Examples of suitable aliphatic and cycloaliphatic polyisocyanates include, but are not limited to, cyclohexane diisocyanate, methylcyclohexane diisocyanate, ethylcyclohexane diisocyanate, propylcyclohexane diisocyanate, methyldiethylcyclohexane diisocyanate, propane diisocyanate, butane diisocyanate, pentane diisocyanate, hexane diisocyanate, heptane diisocyanate, octane diisocyanate, nonane diisocyanate, nonane triisocyanate, such as 4-isocyanatomethyl-1,8-octane diisocyanate (TIN), decane diisocyanate and decane triisocyanate, undecane diisocyanate and undecane triisocyanate and dodecane diisocyanate and dodecane triisocyanate, isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), diisocyanatodicyclohexylmethane (H12g MDI), 2-methylpentane diisocyanate (MPDI), 2,2,4-trimethylhexamethylene diisocyanate / 2,4,4-trimethylhexamethylene diisocyanate (TMDI), norbornane diisocyanate (NBDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate, and dimers, trimers (isocyanurate), such as trimers of hexane-1,6 diisocyanate, and mixtures of the above.

[0087] According to a preferred embodiment of this aspect of the application, the isocyanate component can also be a compound derived from the reaction of one or more of the above polyisocyanates with a compound having isocyanate-reactive functionality. For example, a mono- or polyhydroxy compound (containing one or more reactive OH groups) can be reacted with one or more of the above polyisocyanates to give a urethane. As an example, one can mention the reaction product of ethylene glycol, propylene glycol, neopentyl glycol or trimethylolpropane with, for example, an aliphatic diisocyanate such as hexane-1,6-diisocyanate or an aromatic diisocyanate such as toluene-2,4-diisocyanate. A preferred urethane is the reaction product of trimethylolpropane with toluene-2,4-diisocyanate, wherein all three OH groups of the trimethylolpropane are reacted with toluene-2,4-diisocyanate:

[0088]

[0089] Although this compound contains three urethane moieties, it is not a urethane oligomer or polyurethane, as it is not composed of any repeating units.

[0090] Likewise, a mono- or polyamine compound, or a mono- or polythiol compound, can be reacted with one or more of the above polyisocyanates, which will result in a urea compound or a thiourethane compound.

[0091] According to a preferred embodiment of this aspect of the present application, the isocyanate component can also be an oligomer. Oligomers can be obtained from the reaction of one or more of the above-mentioned polyisocyanates with a compound having at least two isocyanate-reactive functional groups, wherein a plurality of repeating units is generated. Such oligomers must comprise at least two free isocyanate (NCO) groups. As an example, one can mention the reaction of ethylene glycol and hexane-1,6-diisocyanate under such conditions to obtain an oligomer of the following formula:

[0092]

[0093] Oligomers are generally defined as having a small number of repeating units (e.g. in the above formula, n is small), whereas polymers are generally defined as having a large number of repeating units (e.g. in the above formula, n is large). However, there is no clear distinction between oligomers and polymers. According to the present application, oligomers are defined as having a weight average molecular weight (Mw) of less than 5000 g / mol.

[0094] The one-component adhesive composition according to this aspect of the present application can also comprise a combination of the above-mentioned isocyanate components comprising at least two free isocyanate moieties.

[0095] Preferably, the one-component adhesive composition according to this aspect of the present application comprises 90 to 20 wt.%, more preferably 80 to 30 wt.%, and especially preferably 30 to 65 wt.% of the at least one isocyanate component comprising at least two free isocyanate moieties, based on the weight of the entire adhesive composition.

[0096] However, it is preferred that the composition does not comprise any polyurethane having a weight average molecular weight of 20000 g / mol or more, preferably 15000 g / mol or more, more preferably 10000 g / mol or more, even more preferably 5000 g / mol or more, preferably 2500 g / mol or more, and most preferably 1000 g / mol or more.

[0097] Polyurethanes are defined as polymers derived from the reaction of one or more of the above-mentioned polyisocyanates with a compound having at least two isocyanate-reactive hydroxyl groups, wherein a plurality of repeating units comprising urethane groups is generated. For example, in the formula shown above and reproduced again below, the repeating units (in brackets) comprise urethane groups, and n is set such that the compound has a weight average molecular weight (Mw) of at least 5000 g / mol:

[0098]

[0099] The one-component adhesive composition according to this aspect of the present application can additionally comprise one or more additives which are commonly used in adhesive compositions. Examples of such additives include, but are not limited to, tackifiers, plasticizers, rheology modifiers, adhesion promoters, antioxidants, fillers, colorants, surfactants, catalysts, and combinations of two or more thereof. Preferably, the one-component adhesive composition according to this aspect of the present application comprises 0 to 5 wt.-%, more preferably 0.1 to 4 wt.-%, and particularly preferably 0.5 to 3 wt.-%, of at least one additive, based on the weight of the entire adhesive composition.

[0100] The one-component adhesive composition according to this aspect of the present application can be prepared by conventional mixing methods such as mixing the above-mentioned ingredients by stirring using a stirrer. Depending on the isocyanate present in the composition, the preparation of the one-component adhesive composition according to the present application can be carried out under inert gas atmosphere, for example under nitrogen.

[0101] According to this aspect, the present application further comprises a method of preparing a laminate comprising the step of applying a one-component adhesive composition to the free surface of a substrate layer in a dry coat weight of less than 1 g / m2 2 , preferably 0.1 to 0.9 g / m2 2 , more preferably 0.2 to 0.8 g / m2 2 , and particularly preferably 0.3 to 0.7 g / m2 2 , and preferably under moisture-free conditions.

[0102] According to a third aspect, the present application relates to a laminate for packaging applications comprising a substrate layer and an adhesive layer present on the surface of said substrate layer, characterized in that said adhesive layer is made of a one-component adhesive composition which is curable under moisture-free conditions.

[0103] "Curable under moisture-free conditions" is to be understood as meaning that the one-component adhesive composition according to the present application does not require any water for curing. It is not necessary to add any water to the composition for curing, or to provide a higher defined air humidity during the process. Furthermore, the one-component adhesive composition according to the present application is curable under very dry conditions of less than 20% RH (relative humidity, preferably less than 10% RH, more preferably less than 5% RH).

[0104] It has been found that according to this aspect of the present application, it is possible to provide an adhesive layer which has a satisfactory adhesive function under moisture-free conditions. Preferably, the laminate application of such a low dry coat weight adhesive layer can also be combined with a substrate which is not grafted with any polar component, but is only corona treated or even untreated.

[0105] According to a preferred embodiment of this aspect, the adhesive layer is made from a one-component adhesive composition and applied in a dry coating weight of less than 1 g / m2 2 , preferably 0.1 to 0.9 g / m2 2 , more preferably 0.2 to 0.8 g / m2 2 , and especially preferably 0.3 to 0.7 g / m2 2 . The dry coating weight can be determined by known methods, for example based on the amount of adhesive composition used, or by weighing the uncoated article and the dried coated article (i.e. the article to which the adhesive layer is applied) and determining the dry coating weight as the difference between these two weights.

[0106] According to a preferred embodiment of this aspect, this can be achieved by using a one-component adhesive composition, wherein the functional groups of the one-component adhesive composition consist of isocyanate moieties and the composition does not comprise any polyurethane having a weight average molecular weight of 20000 g / mol or more, preferably 15000 g / mol or more, more preferably 10000 g / mol or more, even more preferably 5000 g / mol or more, particularly preferably 2500 g / mol or more, and most preferably 1000 g / mol or more.

[0107] According to a preferred embodiment of this aspect, the concentration of isocyanate groups of the one-component adhesive composition is 0.5 to 10 %, preferably 1 to 9 %, more preferably 2 to 8 %, and especially preferably 3 to 7 %, based on the weight of the total amount of the composition.

[0108] According to the present invention of this aspect, the concentration of isocyanate groups is the amount of isocyanate groups in the composition, based on the weight of the total amount of the composition.

[0109] According to this aspect, the present invention is not limited to the use of one-component adhesive compositions, wherein the functional groups of the one-component adhesive composition consist of isocyanate moieties. Other one-component adhesive compositions based on different functional groups can also be suitable.

[0110] For example, compounds having reactive groups such as epoxy, silane, maleic anhydride, carbodiimide and aziridine can be used.

[0111] As used herein, the term "epoxy" denotes a cyclic ether functional group, wherein an oxygen atom is attached to two adjacent carbon atoms. The term "compound having an epoxy group" is intended to encompass polyepoxide compounds (having two or more epoxy groups). Suitable epoxy compounds can be saturated or unsaturated, aliphatic, cycloaliphatic, aromatic or heterocyclic and can be substituted. Furthermore, the epoxy compounds can also be monomeric, oligomeric or polymeric.

[0112] Suitable polyepoxide compounds can be liquid, solid or in solution in a solvent. Furthermore, such polyepoxide compounds should have an epoxy equivalent weight of 100 to 700 g / eq, for example 120 to 320 g / eq. According to the present application, diepoxide compounds having an epoxy equivalent weight of less than 500 g / eq or even less than 400 g / eq are preferred. Exemplary polyepoxide compounds can be glycidyl ethers of polyhydric alcohols and polyhydric phenols; glycidyl esters of polybasic carboxylic acids; and epoxidized polyethylenically unsaturated hydrocarbons, esters, ethers and amides.

[0113] Suitable diglycidyl ether compounds can be aromatic, aliphatic or cycloaliphatic, such as diglycidyl ethers of aliphatic and cycloaliphatic diols such as 1,2-ethanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,12-dodecanediol, cyclopentanediol and cyclohexanediol; bisphenol A based diglycidyl ethers; bisphenol F diglycidyl ethers; polyalkylene glycol based diglycidyl ethers, in particular polypropylene glycol diglycidyl ethers; and polycarbonate diol based glycidyl ethers.

[0114] Exemplary polyepoxide compounds are glycerol polyglycidyl ethers; trimethylolpropane polyglycidyl ethers; pentaerythritol polyglycidyl ethers; diglycerol polyglycidyl ethers; polyglycerol polyglycidyl ethers; and sorbitol polyglycidyl ethers.

[0115] The term "compound having silane groups" is intended to encompass any compound containing silane groups, preferably silane-terminated polyethers, silane-terminated polyurethanes such as silanes based on aminoalkyl-functional, diisocyanates and polyethers, and polyesters, polyether and / or polyurethane prepolymers having at least two hydrolysable alkoxysilane groups, wherein the prepolymers have a molecular weight of 2000 to 30000 g / mol.

[0116] The term "compound having maleic anhydride groups" is intended to encompass oligomers and prepolymers having two or more maleic anhydride groups, preferably terminal maleic anhydride groups. For example, maleic anhydride-styrene polymers or alkyl vinyl ether-maleic anhydride type copolymers can be mentioned.

[0117] The term "compound having carbodiimide groups" is intended to encompass compounds containing two or more carbodiimide functional groups, such as CX-300 from Covestro.

[0118] The term "aziridine group" is intended to encompass cyclic amino functional groups in which a nitrogen atom is attached to two adjacent carbon atoms. The term "compound having an aziridine group" is intended to encompass polyaziridine compounds (having two or more aziridine groups). Suitable aziridine compounds can be saturated or unsaturated, aliphatic, alicyclic, aromatic, or heterocyclic, and can be substituted. Furthermore, aziridine compounds can also be monomeric, oligomeric, or polymeric.

[0119] Preferred compounds include trimethylolpropane tris(3-aziridinylpropionate, trimethylolpropane tris(3-(2-methylaziridinyl)propionate), trimethylolpropane tris[2-aziridinylbutyrate], trimethylolpropane tris-[β-(N-aziridinyl)propionate], tris(1-aziridinyl)phosphine oxide, tris(2-methyl-1-aziridinyl)phosphine oxide, pentaerythritol tris[3-(1-aziridinyl)propionate], pentaerythritol tris[β-(N-aziridinyl)propionate] and pentaerythritol tetrakis[3-(1-aziridinyl)propionate].

[0120] The present invention provides a solution that is widely applicable to lamination and overcomes the shortcomings associated with two-component adhesive compositions. There is no need to mix the individual components at the manufacturer's site, so mixing errors cannot occur. There is no problem of any remaining components because there is no need to mix the individual components, which may produce any remaining unused raw materials. In addition, the limited pot life of 2K-adhesive systems, which is caused by the reaction of the two components during processing and the increase in viscosity and the decrease in bond strength values, is not a problem for 1K-adhesive systems because no reaction occurs between the two components. Therefore, waste is reduced or avoided. It is not necessary to provide mixing equipment for mixing the individual components of the two-component adhesive composition, thereby reducing costs and cleaning time. Raw material costs and storage costs can be reduced.

[0121] In addition, the one-component adhesive composition of this aspect of the present invention does not contain a polyhydroxy polyol component. This results in a reduction in the dry coating weight of the adhesive layer made from the one-component adhesive composition of the present invention. Therefore, the adhesive layer made from the one-component adhesive composition of this aspect of the present invention also has a higher content of recyclable materials (percentage of polymer in the packaging structure) and improves the overall recyclability of the laminate made therefrom, and accordingly improves the overall recyclability of the flexible packaging made from the laminate.

[0122] The one-component adhesive composition according to this aspect of the invention has lower formulation complexity due to its simpler composition, and also has more robust application properties compared to conventional two-component adhesive compositions.

[0123] In particular, it has been found that the use of the one-component adhesive composition according to this aspect of the present application can result in higher adhesion strength values at lower dry coating weights compared to conventional two-component adhesive compositions.

[0124] Furthermore, faster curing is observed with the use of the one-component adhesive composition according to this aspect of the present application compared to conventional two-component adhesive compositions.

[0125] Very good stability under retort conditions (as are typically used for sterilization purposes) is also observed for the one-component adhesive composition according to this aspect of the present application.

[0126] The one-component adhesive composition according to this aspect of the present application is solvent borne. Thus, the composition comprises at least one organic solvent. Any organic solvent conventionally used in adhesive compositions can be used. Examples are esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, neopentyl acetate, acetone or MEK (methyl ethyl ketone). The one-component adhesive composition according to the present application can also comprise a mixture of any of the above-mentioned organic solvents. Preferably, the one-component adhesive composition according to the present application comprises 10 to 80 wt.%, more preferably 20 to 70 wt.%, and particularly preferably 30 to 65 wt.% of the at least one solvent, based on the weight of the entire adhesive composition.

[0127] The one-component adhesive composition according to this aspect of the present application is preferably so constituted that the functional group of the one-component consists of isocyanate moieties. In other words, in a preferred embodiment of this aspect of the present application, the one-component does not have any other functional group than isocyanate moieties. By "functional group" is meant a chemical group that contributes to the curing reaction to obtain an adhesive layer from the one-component adhesive composition. Such functional group is a free (i.e. unreacted) functional group and does not contain internal groups such as ether, ester or carbamate groups derived from the reaction of starting materials such as from two alcohols, an alcohol and an acid, or an alcohol and an isocyanate.

[0128] The one-component adhesive composition according to this aspect of the present application preferably comprises an isocyanate component comprising at least two free isocyanate moieties. The isocyanate component can be a polyisocyanate (i.e. an isocyanate having more than one unreacted isocyanate moiety) or an isocyanate oligomer.

[0129] The isocyanate component can be selected from the group consisting of aromatic polyisocyanates, aliphatic polyisocyanates, cycloaliphatic polyisocyanates, and combinations of two or more thereof. By "aromatic polyisocyanate" is meant a polyisocyanate containing one or more aromatic rings. By "aliphatic polyisocyanate" is meant a polyisocyanate not containing aromatic rings. By "cycloaliphatic polyisocyanate" is meant an aliphatic polyisocyanate containing at least one aliphatic ring structure.

[0130] Suitable aromatic polyisocyanates include 3 to 16 carbon atoms, more preferably 4 to 12 carbon atoms, and 2 to 5, preferably 2 to 4 free unreacted isocyanate moieties. Preferred polyisocyanates include, but are not limited to, 1,3-phenylene diisocyanate and 1,4-phenylene diisocyanate, 1,5- naphthalene diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate (2,4-TDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 3,3'-dimethyl-4,4'-biphenylene diisocyanate (TODI), polymeric isocyanates, and combinations of two or more thereof.

[0131] Suitable aliphatic polyisocyanates can be straight chain or branched aliphatic hydrocarbons having 3 to 16 carbon atoms, more preferably 4 to 12 carbon atoms, and 2 to 5, preferably 2 to 4 free unreacted isocyanate moieties in the alkylene residue.

[0132] Suitable cycloaliphatic polyisocyanates desirably have 4 to 18 carbon atoms, more preferably 4 to 12 carbon atoms, and 2 to 5, preferably 2 to 4 free unreacted isocyanate moieties.

[0133] Examples of suitable aliphatic and cycloaliphatic polyisocyanates include, but are not limited to, cyclohexane diisocyanate, methylcyclohexane diisocyanate, ethylcyclohexane diisocyanate, propylcyclohexane diisocyanate, methyldiethylcyclohexane diisocyanate, propane diisocyanate, butane diisocyanate, pentane diisocyanate, hexane diisocyanate, heptane diisocyanate, octane diisocyanate, nonane diisocyanate, nonane triisocyanate, such as 4-isocyanatomethyl-1,8-octane diisocyanate (TIN), decane diisocyanate and decane triisocyanate, undecane diisocyanate and undecane triisocyanate, and dodecane diisocyanate and dodecane triisocyanate, isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), diisocyanatodicyclohexylmethane (H12MDI), 2-methylpentane diisocyanate (MPDI), 2,2,4-trimethylhexamethylene diisocyanate / 2,4,4-trimethylhexamethylene diisocyanate (TMDI), norbornane diisocyanate (NBDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate, and dimers, trimers (isocyanurate), such as trimers of hexane-1,6 diisocyanate, and mixtures of the above.

[0134] According to a preferred embodiment of this aspect of the present application, the isocyanate component can also be a compound derived from the reaction of one or more of the above-mentioned polyisocyanates with a compound having isocyanate-reactive functional groups. For example, a mono- (containing only one reactive OH group) or polyhydroxy (containing more than one reactive OH group) compound can be reacted with one or more of the above-mentioned polyisocyanates to give a urethane. As an example, one can mention the reaction product of ethylene glycol, propylene glycol, neopentyl glycol or trimethylolpropane with, for example, an aliphatic diisocyanate such as hexane-1,6-diisocyanate or an aromatic diisocyanate such as toluene-2,4-diisocyanate. A preferred urethane is the reaction product of trimethylolpropane with toluene-2,4-diisocyanate, wherein all three OH groups of the trimethylolpropane are reacted with toluene-2,4-diisocyanate:

[0135]

[0136] Although this compound contains three urethane moieties, it is not a urethane oligomer or a polyurethane, as it is not composed of any repeating units.

[0137] Likewise, a mono- or polyamine compound, or a mono- or polythiol compound can be reacted with one or more of the above-mentioned polyisocyanates, which will result in a urea compound or a thiocarbamate compound.

[0138] According to a preferred embodiment of this aspect of the present application, the isocyanate component can also be an oligomer. Oligomers can be obtained from the reaction of one or more of the above-mentioned polyisocyanates with a compound having at least two isocyanate-reactive functional groups, wherein a number of repeating units is generated. Such an oligomer must contain at least two free isocyanate (NCO) groups. As an example, one can mention the reaction of ethylene glycol and hexane-1,6-diisocyanate under such conditions that an oligomer of the following formula is obtained:

[0139]

[0140] Oligomers are generally defined as having a small number of repeating units (for example in the above formula, n is small), whereas polymers are generally defined as having a large number of repeating units (for example in the above formula, n is large). However, there is no clear distinction between oligomers and polymers. According to the present application, oligomers are defined as having a weight average molecular weight (Mw) of less than 5000 g / mol.

[0141] The one-component adhesive composition according to this aspect of the present application can also comprise a combination of the above-mentioned isocyanate components comprising at least two free isocyanate moieties.

[0142] Preferably, the one-component adhesive composition according to this aspect of the invention comprises 90 to 20 wt %, more preferably 80 to 30 wt %, and particularly preferably 30 to 65 wt % of the at least one isocyanate component comprising at least two free isocyanate moieties, based on the weight of the entire adhesive composition.

[0143] However, it is preferred that the composition does not contain any polyurethane having a weight average molecular weight of 20,000 g / mol or more, preferably 15,000 g / mol or more, more preferably 10,000 g / mol or more, even more preferably 5,000 g / mol or more, preferably 2,500 g / mol or more, and most preferably 1,000 g / mol or more.

[0144] Polyurethanes are defined as polymers derived from the reaction of one or more of the above-mentioned polyisocyanates with a compound having at least two isocyanate-reactive hydroxyl groups, resulting in a plurality of repeating units comprising urethane groups. For example, in the formula shown above and reproduced again below, the repeating units (in brackets) comprise urethane groups, and n is set so that the compound has a weight-average molecular weight (Mw) of at least 5000 g / mol:

[0145]

[0146] The one-component adhesive composition according to this aspect of the present invention can additionally comprise one or more additives that are commonly used in adhesive compositions.The example of such additive includes but is not limited to tackifiers, plasticizers, rheology modifiers, adhesion promoters, antioxidants, fillers, coloring agents, surfactants, catalysts, and two or more combinations thereof.Preferably, based on the weight of the whole adhesive composition, the one-component adhesive composition according to this aspect of the present invention comprises 0 to 5 % by weight, more preferably 0.1 to 4 % by weight, and particularly preferably 0.5 to 3 % by weight of at least one additive.

[0147] The one-component adhesive composition according to this aspect of the present invention can be prepared by conventional mixing methods, such as mixing the above-mentioned ingredients using a stirrer. Depending on the presence of isocyanate in the composition, the preparation of the one-component adhesive composition according to the present invention can be carried out under an inert gas atmosphere (e.g., under nitrogen).

[0148] According to this aspect, the present invention also includes a method for preparing a laminate comprising the steps of applying a one-component adhesive composition to the free surface of a substrate layer, preferably in the absence of moisture, and further preferably by applying the one-component adhesive composition at a rate of less than 1 g / m 2 , preferably 0.1 to 0.9 g / m 2, more preferably 0.2 to 0.8 g / m 2 , particularly preferably 0.3 to 0.7 g / m 2 A dry coating weight of 1000 sq. ft. is applied to the free surface of the substrate layer.

[0149] According to a fourth aspect, the present invention relates to a laminate for packaging applications, comprising a substrate layer and an adhesive layer present on the surface of the substrate layer, characterized in that the adhesive layer is made of a one-component adhesive composition having an isocyanate group concentration in the range of 0.5 to 10%, preferably 1 to 9%, more preferably 2 to 8%, and especially preferably 3 to 7%.

[0150] According to this aspect of the invention, the concentration of isocyanate groups is the amount of isocyanate groups in the composition, based on the weight of the total amount of the composition.

[0151] It has been found that a one-component adhesive composition containing NCO groups in an amount within this range provides the advantages of the present invention, such as application of an adhesive layer with a lower dry coating weight while providing good adhesive properties and curing the adhesive layer in the absence of moisture.

[0152] It has been found that according to this aspect of the invention, an adhesive layer having a satisfactory adhesive function in the absence of moisture can be provided. Preferably, lamination applications applying such low dry coating weight adhesive layers can also be combined with substrates that have not been grafted with any polar component, but have only been corona treated or even untreated.

[0153] "Curing in the absence of moisture" should be understood to mean that the one-component adhesive composition according to the present invention does not require any water for curing, or that a high, defined atmospheric moisture level is provided during the process. It is not necessary to add any water to the composition for curing. Furthermore, the one-component adhesive composition according to the present invention is curable under very dry conditions of less than 20% RH (relative humidity, preferably less than 10% RH, and more preferably less than 5% RH).

[0154] According to a preferred embodiment of this aspect, the adhesive layer is made of a one-component adhesive composition and has a density of less than 1 g / m 2 , preferably 0.1 to 0.9 g / m 2 , more preferably 0.2 to 0.8 g / m 2 , particularly preferably 0.3 to 0.7 g / m 2The dry coating weight can be determined by known methods, for example, based on the amount of adhesive composition used, or by weighing an uncoated article and a dry coated article (i.e., the article to which the adhesive layer is applied) and determining the dry coating weight as the difference between the two weights.

[0155] According to a preferred embodiment of this aspect, this can be achieved by using the one-component adhesive composition, wherein the functional groups of the one-component adhesive composition consist of isocyanate moieties and the composition does not contain any polyurethane having a weight average molecular weight of 20,000 g / mol or more, preferably 15,000 g / mol or more, more preferably 10,000 g / mol or more, even more preferably 5,000 g / mol or more, particularly preferably 2,500 g / mol or more, and most preferably 1,000 g / mol or more.

[0156] The present invention provides a solution that is widely applicable to lamination and overcomes the shortcomings associated with two-component adhesive compositions. There is no need to mix the individual components at the manufacturer's site, so mixing errors cannot occur. There is no problem of any remaining components because there is no need to mix the individual components, which may produce any remaining unused raw materials. In addition, the limited pot life of 2K-adhesive systems, which is caused by the reaction of the two components during processing and the increase in viscosity and the decrease in bond strength values, is not a problem for 1K-adhesive systems because no reaction occurs between the two components. Therefore, waste is reduced or avoided. It is not necessary to provide mixing equipment for mixing the individual components of the two-component adhesive composition, thereby reducing costs and cleaning time. Raw material costs and storage costs can be reduced.

[0157] In addition, the one-component adhesive composition of this aspect of the present invention does not contain a polyhydroxy polyol component. This results in a reduction in the dry coating weight of the adhesive layer made from the one-component adhesive composition of the present invention. Therefore, the adhesive layer made from the one-component adhesive composition of this aspect of the present invention also has a higher content of recyclable materials (percentage of polymer in the packaging structure) and improves the overall recyclability of the laminate made therefrom, and accordingly improves the overall recyclability of the flexible packaging made from the laminate.

[0158] The one-component adhesive composition according to this aspect of the invention has lower formulation complexity due to its simpler composition, and also has more robust application properties compared to conventional two-component adhesive compositions.

[0159] In particular, it has been found that higher bond strength values ​​can be achieved at lower dry coat weights using the one-part adhesive composition according to this aspect of the invention compared to conventional two-part adhesive compositions.

[0160] Furthermore, a faster curing is observed using the one-component adhesive composition according to this aspect of the present application compared to conventional two-component adhesive compositions.

[0161] Using the one-component adhesive composition according to this aspect of the present application, also a very good stability under autoclave conditions (as usually used for sterilization purposes) is observed.

[0162] The one-component adhesive composition according to this aspect of the present application is solvent borne. Thus, the composition comprises at least one organic solvent. Any organic solvent conventionally used in adhesive compositions can be used. Examples are esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, neopentyl acetate, acetone or MEK (methyl ethyl ketone). The one-component adhesive composition according to the present application can also comprise a mixture of any of the above-mentioned organic solvents. Preferably, the one-component adhesive composition according to the present application comprises 10 to 80 wt.%, more preferably 20 to 70 wt.%, and particularly preferably 30 to 65 wt.% of the at least one solvent, based on the weight of the entire adhesive composition.

[0163] The one-component adhesive composition according to this aspect of the present application is so constituted that the functional group of the one-component consists of isocyanate moieties. In other words, in a preferred embodiment of this aspect of the present application, the one-component does not have any other functional group than isocyanate moieties. By "functional group" is meant a chemical group which contributes to the curing reaction to obtain an adhesive layer from the one-component adhesive composition. Such functional group is a free (i.e. unreacted) functional group and does not contain internal groups such as ether, ester or carbamate groups derived from the reaction of starting materials such as from two alcohols, an alcohol and an acid, or an alcohol and an isocyanate.

[0164] The one-component adhesive composition according to this aspect of the present application comprises an isocyanate component comprising at least two free isocyanate moieties. The isocyanate component can be an isocyanate monomer, a polyisocyanate (i.e. an isocyanate having more than one unreacted isocyanate moiety) or an isocyanate oligomer.

[0165] The isocyanate component can be selected from the group consisting of aromatic polyisocyanates, aliphatic polyisocyanates, cycloaliphatic polyisocyanates, and combinations of two or more thereof. By "aromatic polyisocyanate" is meant a polyisocyanate containing one or more aromatic rings. By "aliphatic polyisocyanate" is meant a polyisocyanate not containing aromatic rings. By "cycloaliphatic polyisocyanate" is meant an aliphatic polyisocyanate containing at least one aliphatic ring structure.

[0166] Suitable aromatic polyisocyanates contain 3 to 16 carbon atoms, more preferably 4 to 12 carbon atoms, and 2 to 5, preferably 2 to 4, free, unreacted isocyanate moieties. Preferred polyisocyanates include, but are not limited to, 1,3-phenylene diisocyanate and 1,4-phenylene diisocyanate, 1,5-naphthylene diisocyanate, 2,6-toluene diisocyanate, 2,4-toluene diisocyanate (2,4-TDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 3,3'-dimethyl-4,4'-biphenyl diisocyanate (TODI), polymeric isocyanates, and combinations of two or more thereof.

[0167] Suitable aliphatic polyisocyanates can be straight or branched chain aliphatic hydrocarbons having from 3 to 16 carbon atoms, more preferably from 4 to 12 carbon atoms in the alkylene residue and from 2 to 5, preferably 2 to 4 free, unreacted isocyanate moieties.

[0168] Suitable cycloaliphatic polyisocyanates advantageously have from 4 to 18 carbon atoms, more preferably from 4 to 12 carbon atoms, and from 2 to 5, preferably 2 to 4, free, unreacted isocyanate moieties.

[0169] Examples of suitable aliphatic and cycloaliphatic polyisocyanates include, but are not limited to, cyclohexane diisocyanate, methylcyclohexane diisocyanate, ethylcyclohexane diisocyanate, propylcyclohexane diisocyanate, methyldiethylcyclohexane diisocyanate, propane diisocyanate, butane diisocyanate, pentane diisocyanate, hexane diisocyanate, heptane diisocyanate, octane diisocyanate, nonane diisocyanate, nonane triisocyanate, such as 4-isocyanatomethyl-1,8-octane diisocyanate (TIN), decane diisocyanate and decane triisocyanate, undecane diisocyanate and dodecane triisocyanate. Ester and dodecane triisocyanate, isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), diisocyanatodicyclohexylmethane (H1gMDI), 2-methylpentane diisocyanate (MPDI), 2,2,4-trimethylhexamethylene diisocyanate / 2,4,4-trimethylhexamethylene diisocyanate (TMDI), norbornane diisocyanate (NBDI), xylylenediisocyanate (XDI), tetramethylxylylenediisocyanate, and dimers, trimers (isocyanurates), trimers such as hexane-1,6 diisocyanate, and mixtures thereof.

[0170] According to a preferred embodiment of this aspect of the invention, the isocyanate component may also be a compound derived from the reaction of one or more of the above-mentioned polyisocyanates with a compound having isocyanate-reactive functional groups. For example, a monohydroxy (containing only one reactive OH group) or polyhydroxy (containing more than one reactive OH group) compound may be reacted with one or more of the above-mentioned polyisocyanates to give a carbamate. As examples, the reaction products of ethylene glycol, propylene glycol, neopentyl glycol or trimethylolpropane with, for example, an aliphatic diisocyanate such as hexane-1,6-diisocyanate or an aromatic diisocyanate such as toluene-2,4-diisocyanate may be mentioned. A preferred carbamate is the reaction product of trimethylolpropane with toluene-2,4-diisocyanate, wherein all three OH groups of the trimethylolpropane are reacted with toluene-2,4-diisocyanate:

[0171]

[0172] Although this compound contains three urethane moieties, it is not a urethane oligomer or a polyurethane because it is not composed of any repeating units.

[0173] Likewise, a monoamine or polyamine compound, or a monothiol or polythiol compound can be reacted with one or more of the above-mentioned polyisocyanates, which will produce a urea compound or a thiourethane compound.

[0174] According to a preferred embodiment of this aspect of the invention, the isocyanate component may also be an oligomer. Oligomers can be obtained by reacting one or more of the above-mentioned polyisocyanates with a compound having at least two isocyanate-reactive functional groups, resulting in multiple repeating units. Such oligomers must contain at least two free isocyanate (NCO) groups. As an example, the reaction of ethylene glycol and hexane-1,6-diisocyanate under such conditions yields an oligomer of the formula:

[0175]

[0176] An oligomer is generally defined as having a small number of repeating units (e.g., in the above formula, n is small), while a polymer is generally defined as having a large number of repeating units (e.g., in the above formula, n is large). However, there is no clear distinction between oligomers and polymers. According to the present invention, an oligomer is defined as having a weight-average molecular weight (Mw) of less than 5000 g / mol.

[0177] The one-part adhesive composition according to this aspect of the invention may also comprise a combination of the above-described isocyanate components comprising at least two free isocyanate moieties.

[0178] Preferably, the one-component adhesive composition according to this aspect of the invention comprises 90 to 20 wt %, more preferably 80 to 30 wt %, and especially preferably 30 to 65 wt %, of at least one isocyanate component comprising at least two free isocyanate moieties, based on the weight of the entire adhesive composition.

[0179] However, it is preferred that the composition does not contain any polyurethane having a weight average molecular weight of 20,000 g / mol or more, preferably 15,000 g / mol or more, more preferably 10,000 g / mol or more, even more preferably 5,000 g / mol or more, preferably 2,500 g / mol or more, and most preferably 1,000 g / mol or more.

[0180] Polyurethanes are defined as polymers derived from the reaction of one or more of the above-mentioned polyisocyanates with a compound having at least two isocyanate-reactive hydroxyl groups, resulting in a plurality of repeating units comprising urethane groups. For example, in the formula shown above and reproduced again below, the repeating units (in brackets) comprise urethane groups, and n is set so that the compound has a weight-average molecular weight (Mw) of at least 5000 g / mol:

[0181]

[0182] The one-component adhesive composition according to this aspect of the present invention can additionally comprise one or more additives that are commonly used in adhesive compositions.The example of such additive includes but is not limited to tackifiers, plasticizers, rheology modifiers, adhesion promoters, antioxidants, fillers, coloring agents, surfactants, catalysts, and two or more combinations thereof.Preferably, based on the weight of the whole adhesive composition, the one-component adhesive composition according to this aspect of the present invention comprises 0 to 5 % by weight, more preferably 0.1 to 4 % by weight, and particularly preferably 0.5 to 3 % by weight of at least one additive.

[0183] The one-component adhesive composition according to this aspect of the present invention can be prepared by conventional mixing methods, such as mixing the above-mentioned ingredients using a stirrer. Depending on the presence of isocyanate in the composition, the preparation of the one-component adhesive composition according to the present invention can be carried out under an inert gas atmosphere (e.g., under nitrogen).

[0184] According to this aspect, the present invention also includes a method for producing a laminate, which comprises the step of applying a one-component adhesive composition to the free surface of a substrate layer, wherein the adhesive layer is made from a one-component adhesive composition having an isocyanate group concentration of 0.5 to 10%, preferably 1 to 9%, more preferably 2 to 8%, and particularly preferably 3 to 7%.

[0185] According to this aspect, the method of preparing the laminate preferably comprises applying the one-component adhesive composition at a concentration of less than 1 g / m 2 , preferably 0.1 to 0.9 g / m 2 , more preferably 0.2 to 0.8 g / m 2 , particularly preferably 0.3 to 0.7 g / m 2 The step of applying the coating to the free surface of the substrate layer with a dry coating weight of 1000 nm and preferably in the absence of moisture.

[0186] The laminated material (laminated product) of the present invention is characterized in that an adhesive layer made of the one-component adhesive composition described in any one of the above aspects is present on the surface of the substrate layer.

[0187] According to the present invention, the terms "substrate" and "substrate layer" are used interchangeably.

[0188] According to the present invention, the term "laminate" refers to a product consisting of a stack of layers, wherein one layer (the outermost or core layer) is defined as a substrate or substrate layer. For example, the substrate layer can be a plastic layer, preferably a transparent plastic layer. Laminates may also preferably include more than one substrate layer, most preferably as the outermost layer, and one or more printed layers, as well as other functional layers, may be provided between these substrate layers.

[0189] According to a preferred embodiment, the laminate of the present invention comprises two substrate layers, but may also comprise more than two substrates.

[0190] According to a preferred embodiment of the present invention, on the surface of the adhesive layer away from the substrate layer, there is a laminate comprising a second substrate layer. In other words, on the surface of the substrate layer there is an adhesive layer made of the one-component adhesive composition described in any one of the above aspects, and on the other surface of the adhesive layer, the laminate comprising the second substrate layer is applied.

[0191] The substrate layers of the laminate can be the same or different and can be any substrate, such as a plastic substrate. Preferably, the substrate is a plastic substrate, such as those conventionally used in the field of plastic laminates. Examples of suitable plastic substrates are polyethylene (PE), such as low-density polyethylene (LDPE), polypropylene (PP), such as cast polypropylene (CPP) or oriented polypropylene (OPP), polyamide (PA), or polyethylene terephthalate (PET). These substrates can be coated with a metallized layer. For example, the substrate can be coated with a layer of a metal oxide such as aluminum oxide. An example is PP ALOX, which is a polypropylene substrate that has been coated with an aluminum oxide layer. Typically, such metallization provides barrier properties.

[0192] According to a preferred embodiment of the present application, the substrate layers are each composed of a material selected from the group consisting of polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyamide, polyethylene terephthalate and polylactide.

[0193] According to a preferred embodiment of the present application, at least one of the substrate layers, i.e. the substrate layer on which the adhesive layer is applied, is selected from the group consisting of a non-functional substrate layer, a coated substrate layer and a corona treated substrate layer. It has been found that the adhesive layer according to the present application can be used for lamination applications in combination with substrates which are not grafted with any polar component but are only corona treated or even untreated.

[0194] Corona treatment is the most widely used surface treatment method in the plastics film and other related industries and has been used for a long time. Corona treatment increases the surface energy of plastic films, foils and paper to improve the wettability and adhesion of inks, coatings and adhesives. Corona treatment uses a low temperature (https: / / en.wikipedia.org / wiki / Corona_discharge) plasma to impart changes in surface properties. Corona (https: / / en.wikipedia.org / wiki / Plasma_(physics)) is generated by applying a high voltage to an electrode with a sharp tip. Materials such as plastic or paper can be passed through the corona plasma thus generated in order to change the surface energy of the material. Corona treatment and devices for carrying out corona treatment are well known.

[0195] According to a preferred embodiment of the present application, the stack further comprises at least one further layer between the second substrate layer and the adhesive layer, the further layer being selected from the group consisting of a primer layer and a functional coating, such as an oxygen barrier layer.

[0196] According to a preferred embodiment of the present application, the primer layer is applied to one of the substrates by applying a primer composition to the substrate. The terms “primer composition” and “primer layer” are known in the art and refer to a composition or layer made therefrom which is applied to the surface of a substrate in order to provide the surface with the properties required for the application of a printed layer thereon. These required properties include, for example, good adhesive properties so that the printed ink layer applied thereon does not separate under normal operating conditions. In addition, depending on the substrate, these required properties can include sufficient smoothness so that the printed ink layer applied thereon shows the desired gloss.

[0197] According to one particularly preferred embodiment of the present application, a primer layer suitable for delamination and / or deinking is applied to one of the substrates. This involves properties such as very good solubility in alkaline aqueous media as well as very good overprintability and water resistance. Such a primer layer suitable for deinking is disclosed, for example, in WO 2021 / 165081 A1.

[0198] In this particularly preferred embodiment, a primer layer is first applied to the substrate, and the print layer is applied to the primer layer (directly or indirectly via at least one intermediate layer). This allows for efficient deinking of the substrate by dissolving the primer layer and thus removing the print layer disposed thereon from the substrate.

[0199] The primer layer can be applied to the substrate by any conventional coating technique, preferably by flexographic printing or gravure printing.

[0200] Gravure printing and flexographic printing are the main printing methods used for printing packaging materials. These methods can be used to print a variety of substrates, such as paper, cardboard or plastic substrates. Gravure printing and flexographic printing methods are well known. For example, reference can be made to Leach / Pierce (Eds.), The printing ink manual, Blueprint, London, 5 th ed. 1993, p. 33-53. The properties of gravure and flexographic inks are also known to those skilled in the art. Reference may be made, for example, to Leach / Pierce (Eds.), The printing ink manual, Blueprint, London, 5 th ed. 1993, pp. 473-598. The contents of each of these chapters are incorporated herein by reference.

[0201] The primer layer is preferably formed so as to obtain a 0.2-1.5 g / m 2 , preferably 0.4-1.3 g / m 2 , especially preferably 0.6-1.0 g / m 2 An amount of the dry coating weight is applied to the substrate.

[0202] According to a preferred embodiment of the present invention, the laminate may further include a barrier layer, such that the barrier layer is positioned between the substrate layers. Such barrier layers are known in the art. Preferably, the barrier layer is an air-impermeable or gas-blocking barrier layer. As an example, a barrier coating such as an ethylene vinyl alcohol (EVOH) coating may be used for the purposes of the present invention. Preferred barrier layers are disclosed in WO2023 / 285183 A1.

[0203] Preferably 0.2 g / m 2 Up to 2 g / m 2 , preferably 0.5 g / m 2 Up to 1.5 g / m 2 , more preferably 0.6 g / m 2 Up to 1.2 g / m 2The barrier layer was applied at a dry solids dry coating weight of 1000 nm.

[0204] According to a preferred embodiment of the present invention, the laminate further comprises at least one ink layer between the second substrate layer and the adhesive layer. Preferably, the at least one ink layer is selected from a white layer, a black ink layer, a colored ink layer and a combination thereof.

[0205] According to a preferred embodiment of the invention, at least one printing ink layer is applied to the side of the primer layer that is not in contact with one of the substrate layers. This results in a laminate of printing ink layers provided between the adhesive layer and the primer layer.

[0206] The ink layer(s) used in the laminate of the present invention may be made from any ink conventionally used in flexible packaging applications. Such inks may be applied to the substrate by any standard technique, preferably by flexographic or gravure printing.

[0207] According to a preferred embodiment of the present invention, a first laminate can be formed by applying a primer composition according to the present invention to a second substrate, and then applying one or more printed ink layers to the free surface of the applied primer layer. An adhesive layer according to the present invention is then applied to the free surface of the first substrate, and the laminates can then be bonded by conventional lamination methods using a conventional laminator. Thus, in this embodiment, the adhesive layer in the final laminate is between the first substrate layer and one printed layer.

[0208] According to another preferred embodiment of the present invention, the laminate according to the present invention can be made up of two substrate layers, and these two substrate layers are interconnected with the adhesive layer of the present invention.Such laminate structure is the representative of the window area of ​​article, wherein does not provide color or white.

[0209] The laminated materials according to the present invention have advantageous properties. For example, the laminated materials according to the present invention are stable under retort conditions used for sterilization, preferably at 110-140°C for 45-120 minutes. Such retort conditions are generally known. Retorts are performed in closed containers or other equipment used for the thermal treatment of food products. Examples include static steam or rotary steam retort conditions.

[0210] Preferably, the laminate according to the invention has a bond strength value provided by the adhesive layer of the invention higher than 1.5 N / 15 mm, as measured using an Instron universal device.

[0211] The present invention also relates to an article comprising the laminate as described above.

[0212] According to the present invention, the article is preferably a flexible packaging.

[0213] Many products, such as food products, are stored in flexible packaging, ie packaging made of a material that exhibits some flexibility and can therefore undergo certain modifications of its shape.

[0214] Flexible packaging is widely used in areas such as food packaging (e.g., retortable pouches, frozen food packaging, frozen food packaging, shelf-stable food packaging, dry goods packaging, liquid food packaging, fast food wrappers and bags), pharmaceutical packaging (e.g., primary packaging, secondary packaging, brochures and instructions), personal hygiene packaging (e.g., soap packaging, hair care packaging, baby care packaging, feminine care packaging, men's care packaging), home care packaging (e.g., detergent packaging, cleaner packaging), agricultural packaging (e.g., herbicide packaging, pest control packaging, fertilizer bags), industrial packaging (e.g., shopping bags, construction wrappers and bags), and pet care packaging (e.g., pet food bags, pet medicine packaging, pet hygiene packaging).

[0215] The present invention also relates to a method for preparing the above-mentioned laminate, which comprises the step of applying a polyurethane-free one-component adhesive composition to the free surface of the substrate layer, the functional groups of the one-component adhesive composition consisting of isocyanate moieties.

[0216] The invention will now be described in more detail with reference to the accompanying non-limiting figures and examples.

[0217] Figure 1 A diagrammatic representation of a laminate according to one embodiment of the present invention is shown.

[0218] exist Figure 1 , a laminate 1 according to one embodiment of the present invention is shown. The laminate 1 includes a first substrate 2 made of a plastic substrate such as PE or OPP, and a second substrate 2' made of a plastic substrate such as PE, PET, metOPP. The first substrate 2 and the second substrate 2' can be the same or different materials.

[0219] On one surface of the second substrate 2', a primer layer 3 according to the invention is applied. On one surface of the primer layer 3 facing away from the substrate 2', a printing ink layer 4 is provided.

[0220] According to any aspect of the present invention, one surface of the other substrate 2 is bonded to the stack of substrate 2 ′, primer layer 3 and print layer 4 via an adhesive layer 5 . Example

[0221] Example 1

[0222] A one-part adhesive composition according to any of the above aspects of the invention was prepared by mixing polyisocyanate and ethyl acetate in the amounts given in Table 1.

[0223] Table 1

[0224]

[0225] For printing, the composition was adjusted to a viscosity of 14-16 mm (DIN cup 4 mm) using ethyl acetate.

[0226] Example 2a

[0227] In the corona treatment (Softal device, maximum power 1.6 kW, at 20 W / m 2 On a PET film (processed at a line speed of 200 m / min), a color ink layer was printed using the following conventional ink composition:

[0228]

[0229] The ink composition was adjusted to a viscosity of 28" / 3 mm DIN cup and printed using a Kochsiek press at 0.8-2 GSM (g / m 2 ) dry coat weight for gravure printing.

[0230] On the free surface of the colored ink layer, a white ink layer was printed using the following conventional ink composition:

[0231]

[0232] The ink composition was adjusted to a viscosity of 28" / 3 mm DIN cup and printed using a Kochsiek press at 0.8-2 GSM (g / m 2 ) dry coat weight for gravure printing.

[0233] Using the one-component adhesive composition according to Example 1a, an anilox roller was used to prepare the adhesive at 1.5 GSM (g / m 2 ) dry coating weight, the adhesive layer was applied to a corona treated (as described above, at 20 W / m 2 , 200 m / min line speed) on a PE film.

[0234] The PE film coated with the adhesive layer was then laminated with the stack comprising the PET film, the colored ink layer and the white ink layer. The lamination was performed using a Labo Combi 400 device (from Nordmecccanica).

[0235] Example 2b

[0236] Example 2a was repeated, but using color and white ink compositions having the following compositions:

[0237] Color ink composition:

[0238]

[0239] White ink composition:

[0240]

[0241] Example 2c

[0242] Example 2a was repeated, but using color and white ink compositions having the following compositions:

[0243] Color ink composition:

[0244]

[0245] White ink composition:

[0246]

[0247] Example 2d

[0248] Example 2a was repeated, but using the one-part adhesive composition according to Example lb.

[0249] Example 2e

[0250] Example 2b was repeated, but using the one-part adhesive composition according to Example lb.

[0251] Example 2f

[0252] Example 2c was repeated, but using the one-part adhesive composition according to Example lb.

[0253] Examples 2g-i

[0254] Examples 2d-2f were repeated, but the one-part adhesive composition according to Example lb was applied at a dry coating weight of 1.2 GSM (g / m 2 ).

[0255] Comparative Example 2j

[0256] Example 2a was repeated, but using a commercial two-part adhesive composition (Morchem CF744 / PL278A, combination of polyol and polyisocyanate components) applied at a dry coating weight of 2.2 GSM (g / m 2 ).

[0257] Comparative Examples 2k-l

[0258] Examples 2b and 2c were repeated, but using a commercial two-part adhesive composition (Morchem CF744 / PL278A, combination of polyol and polyisocyanate components) applied at a dry coating weight of 3 GSM (g / m 2A commercial two-component adhesive composition (COIM 272 / CA 12, a combination of polyol and polyisocyanate components) was applied at a dry coating weight of 100 ng / min.

[0259] Bond Strength Value (BSV)

[0260] The bond strength values ​​were measured using an Instron 3365. The peel was measured at a 90° angle.

[0261] The following results were obtained:

[0262]

[0263] Film splitting indicates bond strength values ​​so high that they cannot be measured because the entire polymer film is torn before the layers can be separated.

[0264] It can be seen that in the examples according to the present invention using the one-component adhesive of the present invention, higher bond strength values ​​can be achieved between the adhesive layer and the ink layer at lower dry coating weights than with commercial two-component adhesives.

[0265] Example 3

[0266] To demonstrate the suitability of a one-component adhesive for the window area of ​​a flexible packaging (where no colored or white ink layer is present), an anilox roller was used to apply a 1.5 GSM (g / m 2 ) was laminated to a PE film as described in Example 2a, the PE film having a stack consisting of a corona-treated PE film and an adhesive layer applied thereto, the adhesive layer being made from a one-component adhesive composition according to Example 1b (as used in Example 2d).

[0267] The resulting laminate was non-separable under the aforementioned bond strength test conditions. Furthermore, no separation was observed under sealing conditions of 120°C and 3 bar for 1 second. The examples demonstrate that high bond strength values ​​can be achieved in the window area and the corresponding sealing area.

[0268] Example 4

[0269] Example 2d was repeated, but using an OPP substrate instead of a PET substrate. The ink composition described in Example 2c was printed on the OPP substrate. Lamination with a corona-treated PE film provided with an adhesive layer made from the composition according to Example 1b was carried out as in Example 2d.

[0270] Also in this example, excellent bond strength values ​​were observed (as was the film split in Example 2).

[0271] Example 5a

[0272] Example 2f was repeated, but using a PE substrate instead of a PET substrate as the substrate, to which the ink layer was applied.

[0273] The bond strength values were measured after one and two days, as described above.

[0274] After one day (under storage conditions of 15 N pressure and room temperature), the BSV measured was 1.5 N / 15 mm. After two days under the same storage conditions, film splitting occurred as in Example 2f.

[0275] Comparative Example 5b

[0276] Example 5a was repeated, but using a commercially available two-component adhesive composition (Henkel LA 3644 / LA 6055 in a mixing ratio of 20:1). After one day, a BSV of 1.2 N / 15 mm was measured. After two days, a BSV of 1.5 N / 15 mm was measured.

[0277] This example shows that faster curing can be achieved using a one-component adhesive composition compared to using a conventional two-component adhesive composition.

[0278] Example 6a

[0279] To test the stability under retort conditions, Example 2c was repeated, but using an aluminum / CPP film as the substrate, to which the one-component adhesive composition according to Example la was applied in a dry coating weight of 1.2 GSM. The BSV before applying the retort conditions was 1.8 N / 15 mm.

[0280] In a Varioklav 75T RG device, retort conditions of 131 °C for 45 minutes in distilled water were applied to the product. Thereafter, the BSV measured was 1.8 N / 15 mm, i.e. unchanged.

[0281] Example 6b

[0282] Example 2f was repeated, but using an aluminum / CPP film as the substrate, to which the one-component adhesive composition according to Example lb was applied in a dry coating weight of 1.2 GSM. The BSV before applying the retort conditions was 2.0 N / 15 mm.

[0283] In a Varioklav 75T RG device, retort conditions of 131 °C for 45 minutes in distilled water were applied to the product. Thereafter, the BSV measured was 2.0 N / 15 mm, i.e. unchanged.

[0284] Examples 6a and 6b show that using the one-component adhesive composition according to the present invention, there is no change in BSV and no channel-like lamination failure occurs under retort conditions.

[0285] Example 7

[0286] Example 4 was repeated, once with an ink layer (Example 7a) and once without an ink layer (Example 7b).The corresponding one-component adhesive composition was applied at a dry coating weight of 0.5 gsm.

[0287] Comparative Example 7

[0288] Example 7 was repeated but using a commercial two-component adhesive composition (Henkel LA7735 / 6159 at a mix ratio of 20:1), which was also applied at a dry coat weight of 0.5 GSM.

[0289] The bond strength values ​​were measured using an Instron 3365. The peel was measured at a 90° angle.

[0290] The following results were obtained:

[0291]

[0292] It can be seen that using the one-component adhesive composition of the present invention, excellent BSV values ​​can be achieved even at a low dry coating weight of 0.5 GSM, whereas the commercial two-component adhesive compositions according to Comparative Examples 7a and 7b fail.

[0293] Example 8

[0294] In this example, the curing of a one-part adhesive composition of the present invention was tested under different humidity conditions.

[0295] Example 7 was repeated, once with an ink layer (Example 8a) and once without an ink layer (Example 8b). The corresponding one-component adhesive composition was applied at a dry coating weight of 1.0 gsm.

[0296] Curing was performed in a desiccator at 0% RH / 20-25°C or 50-75% RH / 20-25°C.

[0297] Comparative Example 8

[0298] Example 8 was repeated, but using a commercially available two-component adhesive composition (Henkel 3644 / 6229 with a 20:1 mix ratio), also applied at a dry coat weight of 1.0 gsm. Curing was performed in a desiccator at either 0% RH / 20-25°C or 50-75% RH / 20-25°C.

[0299] The following results were obtained:

[0300]

[0301] It can be seen that using the one-component adhesive composition of the present invention, excellent BSV values ​​can be achieved even under moisture-free curing conditions, which are comparable to or even better than the BSV values ​​of commercially available 2K adhesive compositions (which are moisture-insensitive due to their 2K composition). It is also noted that the one-component adhesive composition of the present invention exhibits even better BSV values ​​when cured under moisture-free curing conditions.

Claims

1. A laminate material (1) for packaging applications, comprising a substrate layer (2) and an adhesive layer (5) present on a surface of the substrate layer (2), characterized in that The adhesive layer (5) is made of a one-component adhesive composition, wherein the functional groups of the one-component consist of isocyanate moieties, and the composition does not contain any polyurethane, and the polyurethane has a weight average molecular weight of 20,000 g / mol or more, preferably 15,000 g / mol or more, more preferably 10,000 g / mol or more, even more preferably 5,000 g / mol or more, particularly preferably 2,500 g / mol or more, and most preferably 1,000 g / mol or more.

2. The laminate according to claim 1, wherein The one-component adhesive composition has an isocyanate group concentration in the range of 0.5 to 10%, preferably 1 to 9%, more preferably 2 to 8%, and particularly preferably 3 to 7%.

3. The laminate according to claim 1 or 2, characterized in that The one-component adhesive composition is curable in the absence of moisture.

4. Laminate according to any one of the preceding claims, characterized in that The adhesive layer (5) is made of a one-component adhesive composition and has a thickness of less than 1 g / m 2 , preferably in the range of 0.1 to 0.9 g / m 2 in the range of 0.2 to 0.8 g / m 2 In the range of 0.3 to 0.7 g / m 2 A range of dry coating weights are applied.

5. Laminate according to any one of the preceding claims, characterized in that The one-component adhesive composition comprises a mixture of polyisocyanates.

6. Laminate according to any one of the preceding claims, characterized in that The one-component adhesive composition is solvent-based.

7. Laminate according to any one of the preceding claims, characterized in that The substrate layer (2) is selected from a non-functional substrate layer, a coated substrate layer and a corona-treated substrate layer.

8. Laminate material according to any one of the preceding claims, characterized in that The substrate layer (2) is composed of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyamide, polyethylene terephthalate and polylactide.

9. Laminate according to any one of the preceding claims, characterized in that On the surface of the adhesive layer (5) remote from the substrate layer (2), there is a laminate comprising a second substrate layer (2').

10. The laminate according to claim 9, characterized in that The second substrate layer (2') is made of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyamide, polyethylene terephthalate and polylactide.

11. The laminate according to claim 9 or 10, characterized in that The laminate further comprises at least one ink layer (4) between the second substrate layer (2') and the adhesive layer (5).

12. The laminate according to claim 11, characterized in that The at least one ink layer (4) is selected from a white layer, a black ink layer, a color ink layer and a combination thereof.

13. The laminate material according to any one of claims 9 to 12, characterized in that The laminate further comprises at least one further layer between the second substrate layer (2') and the adhesive layer (5), the further layer being selected from a primer layer (3) and a functional coating, such as an oxygen barrier layer.

14. Laminate material according to any one of the preceding claims, characterized in that The laminate (1) is stable under retort conditions for sterilization, preferably at 110-140°C for 45-120 minutes.

15. An article comprising the laminate (1) according to any one of claims 1 to 14.

16. The product according to claim 15, characterized in that The article is a flexible package.

17. A method for preparing a laminated material (1) according to any one of claims 1 to 14, comprising the following steps: A polyurethane-free one-component adhesive composition whose functional groups consist of isocyanate moieties is applied to the free surface of the substrate layer (2), preferably in the absence of moisture.

18. The method according to claim 17, characterized in that The substrate layer (2) is composed of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyamide, polyethylene terephthalate and polylactide, and is preferably selected from a non-functional substrate layer and a corona-treated substrate layer.

19. The method according to claim 17 or 18, characterized in that The adhesive layer (5) has a thickness of less than 1 g / m 2 , preferably in the range of 0.1 to 0.9 g / m 2 in the range of 0.2 to 0.8 g / m 2 In the range of 0.3 to 0.7 g / m 2 A range of dry coating weights are applied.

20. A laminate material (1) for packaging applications, comprising a substrate layer (2) and an adhesive layer (5) present on a surface of the substrate layer (2), characterized in that The adhesive layer (5) is made of a one-component adhesive composition and has a thickness of less than 1 g / m 2 , preferably 0.1 to 0.9 g / m 2 In the range of 0.2 to 0.8 g / m 2 In the range of 0.3 to 0.7 g / m 2 A range of dry coating weights are applied.

21. The laminate according to claim 20, characterized in that The functional groups of the one-component adhesive composition consist of isocyanate moieties, and the composition does not contain any polyurethane having a weight average molecular weight of 20,000 g / mol or more, preferably 15,000 g / mol or more, more preferably 10,000 g / mol or more, even more preferably 5,000 g / mol or more, particularly preferably 2,500 g / mol or more, and most preferably 1,000 g / mol or more.

22. The laminate according to claim 20 or 21, characterized in that The one-component adhesive composition has an isocyanate group concentration in the range of 0.5 to 10%, preferably 1 to 9%, more preferably 2 to 8%, and particularly preferably 3 to 7%.

23. The laminate material according to any one of claims 20 to 22, characterized in that The one-component adhesive composition is curable in the absence of moisture.

24. The laminate material according to any one of claims 20 to 23, characterized in that The one-component adhesive composition comprises a mixture of polyisocyanates.

25. The laminate material according to any one of claims 20 to 24, characterized in that The one-component adhesive composition is solvent-based.

26. The laminate material according to any one of claims 20 to 25, characterized in that The substrate layer (2) is selected from a non-functional substrate layer, a coated substrate layer and a corona-treated substrate layer.

27. The laminate material according to any one of claims 20 to 26, characterized in that The substrate layer (2) is composed of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyethylene terephthalate and polylactide.

28. The laminate material according to any one of claims 20 to 27, characterized in that On the surface of the adhesive layer (5) remote from the substrate layer (2), there is a laminate comprising a second substrate layer (2').

29. The laminate according to claim 28, characterized in that The second substrate layer (2') is made of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyethylene terephthalate and polylactide.

30. The laminate according to claim 28 or 29, characterized in that The laminate further comprises at least one ink layer (4) between the second substrate layer (2') and the adhesive layer (5).

31. The laminate material of claim 309, wherein: The at least one ink layer (4) is selected from a white layer, a black ink layer, a color ink layer and a combination thereof.

32. The laminate material according to any one of claims 28 to 31, characterized in that The laminate further comprises at least one further layer between the second substrate layer (2') and the adhesive layer (5), the further layer being selected from a primer layer (3) and a functional coating, such as an oxygen barrier layer.

33. The laminate material according to any one of claims 20 to 32, characterized in that The laminate (1) is stable under retort conditions for sterilization, preferably at 110-140°C for 45-120 minutes.

34. An article comprising the laminate (1) according to any one of claims 20 to 33.

35. The article of claim 34, wherein: The article is a flexible package.

36. A method for preparing a laminate (1) according to any one of claims 20 to 33, comprising the following steps: The single-component adhesive composition is less than 1 g / m 2 , preferably 0.1 to 0.9 g / m 2 In the range of 0.2 to 0.8 g / m 2 In the range of 0.3 to 0.7 g / m 2 The dry coating weight is within the range of , and is preferably applied to the free surface of the substrate layer (2) in the absence of moisture.

37. The method according to claim 36, wherein The substrate layer (2) is composed of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyethylene terephthalate and polylactide, and is preferably selected from a non-functional substrate layer and a corona-treated substrate layer.

38. A laminate material (1) for packaging applications, comprising a substrate layer (2) and an adhesive layer (5) present on a surface of the substrate layer (2), characterized in that The adhesive layer (5) is made of a one-component adhesive composition that is curable in the absence of moisture.

39. The laminate according to claim 38, characterized in that The functional groups of the one-component adhesive composition consist of isocyanate moieties, and the composition does not contain any polyurethane having a weight average molecular weight of 20,000 g / mol or more, preferably 15,000 g / mol or more, more preferably 10,000 g / mol or more, even more preferably 5,000 g / mol or more, particularly preferably 2,500 g / mol or more, and most preferably 1,000 g / mol or more.

40. The laminate material according to claim 38 or 39, characterized in that The adhesive layer (5) is made of a one-component adhesive composition and has a thickness of less than 1 g / m 2 , preferably in the range of 0.1 to 0.9 g / m 2 In the range of 0.2 to 0.8 g / m 2 In the range of 0.3 to 0.7 g / m 2 A range of dry coating weights are applied.

41. The laminate material according to any one of claims 38 to 40, characterized in that The one-component adhesive composition has an isocyanate group concentration in the range of 0.5 to 10%, preferably 1 to 9%, more preferably 2 to 8%, and particularly preferably 3 to 7%.

42. The laminate material according to any one of claims 38 to 41, characterized in that The one-component adhesive composition comprises a mixture of polyisocyanates.

43. The laminate material according to any one of claims 38 to 42, characterized in that The one-component adhesive composition is solvent-based.

44. The laminate material according to any one of claims 38 to 43, characterized in that The substrate layer (2) is selected from a non-functional substrate layer and a corona-treated substrate layer.

45. The laminate material according to any one of claims 38 to 44, characterized in that The substrate layer (2) is composed of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyethylene terephthalate and polylactide.

46. ​​The laminate material according to any one of claims 38 to 45, characterized in that On the surface of the adhesive layer (5) remote from the substrate layer (2), there is a laminate comprising a second substrate layer (2').

47. The laminate according to claim 46, characterized in that The second substrate layer (2') is made of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyethylene terephthalate and polylactide.

48. The laminate according to claim 46 or 47, characterized in that The laminate further comprises at least one ink layer (4) between the second substrate layer (2') and the adhesive layer (5).

49. The laminate according to claim 48, characterized in that The at least one ink layer (4) is selected from a white layer, a black ink layer, a color ink layer and a combination thereof.

50. The laminate material according to any one of claims 38 to 49, characterized in that The laminate further comprises at least one further layer between the second substrate layer (2') and the adhesive layer (5), the further layer being selected from a primer layer (3) and a functional coating, such as an oxygen barrier layer.

51. The laminate material according to any one of claims 38 to 50, characterized in that The laminate (1) is stable under retort conditions for sterilization, preferably at 110-140°C for 45-120 minutes.

52. An article comprising the laminate (1) according to any one of claims 38 to 51.

53. The article of claim 52, wherein: The article is a flexible package.

54. A method for preparing a laminate material (1) according to any one of claims 38 to 51, comprising the following steps: The one-component adhesive composition is applied to the free surface of the substrate layer (2), preferably in the absence of moisture.

55. The method according to claim 54, characterized in that The substrate layer (2) is composed of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyethylene terephthalate and polylactide, and is preferably selected from a non-functional substrate layer and a corona-treated substrate layer.

56. The method according to claim 54 or 55, characterized in that The single-component adhesive composition has a density of less than 1 g / m 2 , preferably in the range of 0.1 to 0.9 g / m 2 in the range of 0.2 to 0.8 g / m 2 In the range of 0.3 to 0.7 g / m 2 A range of dry coating weights are applied.

57. A laminate material (1) for packaging applications, comprising a substrate layer (2) and an adhesive layer (5) present on a surface of the substrate layer (2), characterized in that The adhesive layer (5) is made of a one-component adhesive composition having an isocyanate group concentration in the range of 0.5 to 10%, preferably 1 to 9%, more preferably 2 to 8%, and particularly preferably 3 to 7%.

58. The laminate according to claim 57, wherein The functional groups of the one-component adhesive composition consist of isocyanate moieties, and the composition does not contain any polyurethane having a weight average molecular weight of 20,000 g / mol or more, preferably 15,000 g / mol or more, more preferably 10,000 g / mol or more, even more preferably 5,000 g / mol or more, particularly preferably 2,500 g / mol or more, and most preferably 1,000 g / mol or more.

59. The laminate according to claim 57 or 58, characterized in that The one-component adhesive composition is curable in the absence of moisture.

60. The laminate material according to any one of claims 57 to 59, characterized in that The adhesive layer (5) has a thickness of less than 1 g / m 2 , preferably 0.1 to 0.9 g / m 2 In the range of 0.2 to 0.8 g / m 2 In the range of 0.3 to 0.7 g / m 2 A range of dry coating weights are applied.

61. The laminate material according to any one of claims 57 to 60, characterized in that The one-component adhesive composition comprises a mixture of polyisocyanates.

62. The laminate material according to any one of claims 57 to 61, characterized in that The one-component adhesive composition is solvent-based.

63. The laminate material according to any one of claims 57 to 62, characterized in that The substrate layer (2) is selected from a non-functional substrate layer and a corona-treated substrate layer.

64. The laminate material according to any one of claims 57 to 63, characterized in that The substrate layer (2) is composed of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyethylene terephthalate and polylactide.

65. A laminate according to any one of claims 57 to 64, characterised in that On the surface of the adhesive layer (5) remote from the substrate layer (2), there is a laminate comprising a second substrate layer (2').

66. The laminate according to claim 65, characterized in that The second substrate layer (2') is made of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyethylene terephthalate and polylactide.

67. The laminate according to claim 65 or 66, characterized in that The laminate further comprises at least one ink layer (4) between the second substrate layer (2') and the adhesive layer (5).

68. The laminate according to claim 67, characterized in that The at least one ink layer (4) is selected from a white layer, a black ink layer, a color ink layer and a combination thereof.

69. The laminate material according to any one of claims 57 to 68, characterized in that The laminate further comprises at least one further layer between the second substrate layer (2') and the adhesive layer (5), the further layer being selected from a primer layer (3) and a functional coating, such as an oxygen barrier layer.

70. The laminate material according to any one of claims 57 to 69, characterized in that The laminate (1) is stable under retort conditions for sterilization, preferably at 110-140°C for 45-120 minutes.

71. An article comprising the laminate (1) according to any one of claims 57 to 70.

72. The article of claim 71, wherein The article is a flexible package.

73. A method of preparing a laminate (1) according to any one of claims 57 to 70, comprising the steps of: A one-component adhesive composition is applied to the free surface of the substrate layer (2), wherein the adhesive layer (5) is made of a one-component adhesive composition having an isocyanate group concentration in the range of 0.5 to 10%, preferably 1 to 9%, more preferably 2 to 8%, and particularly preferably 3 to 7%.

74. The method according to claim 73, characterized in that The substrate layer (2) is composed of a material selected from polyethylene, polypropylene, preferably oriented polypropylene or metallized oriented polypropylene, polyethylene terephthalate and polylactide, and is preferably selected from a non-functional substrate layer and a corona-treated substrate layer.

75. The method according to claim 73 or 74, characterized in that The single-component adhesive composition has a density of less than 1 g / m 2 , preferably in the range of 0.1 to 0.9 g / m 2 in the range of 0.2 to 0.8 g / m 2 In the range of 0.3 to 0.7 g / m 2 The coating is applied in a dry coating weight range of 100 to 200 nm and preferably in the absence of moisture.

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