Two-component composition

Abstract

The invention relates to a two-component composition comprising:-a component A comprising the reaction product obtained by reacting at least:-an aliphatic polyisocyanate, and-a crystalline polyester polyol having a number average molecular weight of less than 3000 g / mol; and-a component B comprising:-at least one polyester polyol,-a chain extender, and-a silane coupling agent. Furthermore, the invention relates to the use of a composition according to the invention as an adhesive for producing articles, which adhesive has an adhesive strength value of greater than or equal to 3.5 N / 15 mm after sterilization. The invention also relates to a multilayer film comprising at least two substrate layers bonded together by a continuous layer, the continuous layer consisting of a two-component composition according to the invention. The invention also relates to the use of a multilayer film according to the invention for producing flexible packaging intended for a sterilization process.

Description

Technical Field

[0001] The invention relates to a two-component composition and its use, as well as a multilayer film and its use. Background Art

[0002] Flexible packaging, in particular for food packaging, generally consists of a plurality of thin layers (in the form of sheets or films) which may be obtained from different materials such as paper, metals (e.g. aluminium) or also thermoplastic polymers. These thin layers are bonded together by adhesive layers, whereas corresponding multilayer films make it possible to combine the properties of the different individual layers of material (also described as “supports”) and thus provide the consumer with a set of characteristics suitable for the final flexible packaging, such as:

[0003] - its visual appearance (in particular printed elements presenting information intended for the consumer regarding the packaged product, or its transparency),

[0004] - barrier effect to light or to atmospheric moisture or to gases, especially to oxygen,

[0005] - come into contact with food without risk of toxicity or alteration of the organoleptic properties of the packaged food,

[0006] - chemical resistance for certain products such as ketchup, and

[0007] -Suitable heat resistance.

[0008] Such heat resistance is understood to mean that the cohesion of the multilayer film is maintained when the multilayer film is exposed to high temperatures and in particular there is no separation between the thin layers bonded by the adhesive layer. Such separation is generally indicated by the term "delamination".

[0009] This heat resistance is necessary for closing packages (eg around food).Such closing generally comprises a heat-sealing step during which the film of the package is subjected to a temperature between 120° C. and 250° C. for a few seconds.

[0010] This heat resistance is also necessary for packaging that undergoes a sterilization process, especially for food packaging. In fact, such a process exposes the multilayer film of the packaging to temperatures between 100°C and 135°C for a period of time that is generally greater than the heat sealing time and can range up to one hour.

[0011] Two-component polyurethane type compositions are widely used as adhesives for the manufacture of multilayer films intended for use in the field of flexible packaging. These two-component compositions comprise:

[0012] - an -NCO component comprising a chemical entity carrying an isocyanate (i.e. -NCO) group, and

[0013] - -OH components, which contain chemical entities carrying hydroxyl (ie -OH) groups.

[0014] After mixing the two components, the isocyanate groups of the -NCO component react with the hydroxyl groups of the -OH component according to a reaction known as crosslinking to form a polyurethane in the form of a three-dimensional network containing urethane groups, providing cohesion of the adhesive layer between the layers of the multilayer film.

[0015] The chemical entities present in the -NCO component are generally polymeric chemical compounds called prepolymers because they are precursors to the final cross-linked polyurethane composition of the adhesive layer. These prepolymers containing -NCO groups are themselves generally polyurethanes produced by the polyaddition reaction of a molar excess of polyisocyanate monomers, which are generally aromatic, such as diphenylmethane diisocyanate (MDI) or toluene diisocyanate (TDI), with one or more polyols.

[0016] However, due to the specificity of the polyaddition reaction and due to the presence of a molar excess of polyisocyanate, a certain amount of unreacted polyisocyanate monomers remains in the -NCO component thus obtained. After use of the two-component composition, these residual amounts ("free") of aromatic polyisocyanate monomers are able to migrate through the multilayer film and thus through the final packaging. Thus, the monomers can form aromatic primary amines (PAAs) by hydrolysis when in contact with water or, in particular, moisture present in the air or in the packaged food. These PAAs are considered to be very harmful to human health and the environment.

[0017] It was therefore an object of the present invention to provide two-component compositions which can be implemented in multilayer films without the risk of subsequent formation of aromatic primary amines.

[0018] In addition, there is an increasing demand for solvent-free adhesives for environmental protection, efficiency and cost reasons. Furthermore, GLYMO ((3-glycidyloxypropyl)trimethoxysilane) and epoxysilanes in general are also regarded as harmful to human health.

[0019] It was therefore a further object of the present invention to provide a two-component composition which is free of solvents and / or free of GLYMO, more generally free of epoxy silanes.

[0020] A further object of the present invention was to provide two-component compositions which can be used as adhesive layer in multilayer films and which can lead to multilayer films having good thermal properties, in particular high bond strength values ​​after sterilization.

[0021] It has now been found that these objects can be achieved by the two-component composition described below. Summary of the invention

[0022] The present invention relates to a two-component composition comprising:

[0023] - Component A, comprising a reaction product obtained by reacting at least:

[0024] - aliphatic polyisocyanates, and

[0025] - a crystalline polyester polyol having a number average molecular weight of less than 3000 g / mol; and

[0026] - Component B comprising:

[0027] - at least one polyester polyol,

[0028] - a chain extender, and

[0029] -Silane coupling agent.

[0030] The invention furthermore relates to articles, in particular multilayer films, comprising at least one surface coated with a two-component composition according to the invention.

[0031] The invention furthermore relates to the use of a composition according to the invention as an adhesive for producing articles, in particular multilayer films, which adhesive has an adhesive strength value after sterilization of greater than or equal to 3.5 N / 15 mm.

[0032] The present invention is also directed to providing a multilayer film comprising at least two substrate layers bonded together by a continuous layer, wherein the continuous layer consists of the two-component composition according to the invention.

[0033] Finally, the invention relates to the use of the multilayer film according to the invention for producing flexible packaging intended for sterilization processes such as the sterilization of food placed in said flexible packaging.

[0034] The present invention makes it possible to solve the needs mentioned above. In particular, the two-component composition according to the invention surprisingly provides multilayer films with good thermal properties, especially high bond strength values ​​after sterilization, while avoiding the risk of forming aromatic primary amines. In addition, the two-component composition according to the invention can advantageously be implemented without the need for solvents or epoxy silanes. DETAILED DESCRIPTION

[0035] The present invention relates to a two-component composition comprising:

[0036] - Component A, comprising a reaction product obtained by reacting at least:

[0037] - aliphatic polyisocyanates, and

[0038] - a crystalline polyester polyol having a number average molecular weight of less than 3000 g / mol; and

[0039] - Component B comprising:

[0040] - at least one polyester polyol,

[0041] - a chain extender, and

[0042] -Silane coupling agent.

[0043] Component A

[0044] Aliphatic polyisocyanate

[0045] "Aliphatic polyisocyanate" is intended to be a compound having at least two isocyanate (i.e. -NCO) groups, wherein the nitrogen atoms of the -NCO groups are not directly connected to a carbon atom as part of an aromatic ring by a covalent bond. For example, m-xylylene diisocyanate (m-xylylene diisocyanate) (m-XDI) is an aliphatic polyisocyanate according to the present invention. In addition, aliphatic polyisocyanates do not contain carbamate groups.

[0046] Thus, "aromatic polyisocyanate" is intended to be a compound having at least two isocyanate (ie, -NCO) groups, wherein at least one nitrogen atom of the -NCO groups is directly attached by a covalent bond to a carbon atom that is part of an aromatic hydrocarbon ring.

[0047] The aliphatic polyisocyanate has a functionality of at least 2, meaning that the number of -NCO groups per molecule of the polyisocyanate is at least 2. Preferably, the aliphatic polyisocyanate has a functionality equal to 2, meaning that the aliphatic polyisocyanate is a diisocyanate.

[0048] Advantageously, the aliphatic polyisocyanate is selected from isophorone diisocyanate (IPDI), dicyclohexylmethane 4,4'-diisocyanate (H12MDI), 1,4-cyclohexylene diisocyanate, 1,2-cyclohexylene diisocyanate, 2,4-diisocyanato-1-methylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, m-xylylene diisocyanate (m-XDI), hydrogenated meta ... diisocyanate, hydrogenated meta-xylyl diisocyanate) (m-H6XDI), tetramethylxylene diisocyanate (TMXDI), 1,2-ethylene diisocyanate, 1,3-propylene diisocyanate, 1,4-butylene diisocyanate, 1,5-pentamethylene diisocyanate (PDI), 1,6-hexamethylene diisocyanate (HDI), and mixtures thereof.

[0049] Preferably, the aliphatic polyisocyanate is selected from isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, 1,4-cyclohexylene diisocyanate, 2,4-diisocyanate-1-methylcyclohexane, 1,3-diisocyanate-2-methylcyclohexane, and mixtures thereof, more preferably isophorone diisocyanate.

[0050] The content of aliphatic polyisocyanate implemented to obtain the reaction product in component A can vary from 30 to 90% by dry weight, preferably from 40 to 80% by dry weight, more preferably from 50 to 70% by dry weight, relative to the total dry weight of component A.

[0051] "Dry weight of X" is intended to be the weight of X without taking into account the weight of possible solvents that may be contained in X. Solvents are well known to those skilled in the art and include, for example, water, ethanol, isopropanol, ethyl acetate, butyl acetate, acetone, butanone, methyl isobutyl ketone, tetrahydrofuran, cyclohexane, benzene, toluene, xylene, and the like.

[0052] In the context of the present invention, ranges of values ​​are understood to be inclusive. For example, a range "between 0% and 25%" specifically includes the values ​​0% and 25%.

[0053] Advantageously, no aromatic polyisocyanate is used to obtain the reaction product in component A. Furthermore, component A is advantageously free of aromatic polyisocyanates.

[0054] Crystalline polyester polyol in component A

[0055] "Crystalline polyester polyol" is intended to be a polyester polyol having a crystallinity of at least 20%, whereas "non-crystalline polyester polyol" is a polyester polyol having a crystallinity of less than 20%. Crystallinity refers to the degree of regularity and structural order in a material or molecular structure. In the present patent application, crystallinity is preferably measured by wide angle X-ray diffraction (WAXD) and according to the following calculation formula known in the art:

[0056]

[0057] in:

[0058] - Xcw is the crystallinity determined by X-ray diffraction;

[0059] -Ic is the crystal diffraction peak intensity;

[0060] -Iw is the amorphous dispersion peak intensity.

[0061] For example, crystallinity can be automatically determined by a Rigaku SmartLab X-ray diffractometer.

[0062] "Polyester polyol" is intended to be a polymer comprising at least two hydroxyl (-OH) groups and at least two ester groups. Preferably, the polyester polyol comprises a backbone comprising ester linkages and terminal ends comprising hydroxyl groups. More preferably, the polyester polyol comprises primary hydroxyl groups, i.e., hydroxyl groups bonded to carbon atoms having exactly one substituent other than a hydrogen atom (and in addition to said hydroxyl groups).

[0063] The crystalline polyester polyol in component A can be obtained by reacting at least one polyol with at least one polycarboxylic acid or an ester-forming derivative thereof, such as anhydride or halide thereof, which is capable of forming an ester bond after reacting with a hydroxyl group.

[0064] The molar ratio of the at least one polyol relative to the at least one polycarboxylic acid may be equal to 1, preferably comprised between 1.02 and 1.7, more preferably between 1.05 and 1.5.

[0065] The polycarboxylic acid may be aliphatic or may contain one or more aromatic rings, preferably the polycarboxylic acid is aliphatic.

[0066] Advantageously, the polycarboxylic acid is selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, fumaric acid or a dimer thereof, maleic acid or a dimer thereof, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, phthalic acid, terephthalic acid, ester-forming derivatives thereof, and mixtures thereof.

[0067] Preferably, the polycarboxylic acid is selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, fumaric acid or its dimer, maleic acid or its dimer, 1,4-cyclohexanedicarboxylic acid, its ester-forming derivatives, and mixtures thereof.

[0068] More preferably, the polycarboxylic acid is selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, ester-forming derivatives thereof, and mixtures thereof.

[0069] Even more preferably, the polycarboxylic acid is selected from adipic acid, suberic acid, sebacic acid, 1,12-dodecanedioic acid, ester-forming derivatives thereof, and mixtures thereof, in particular adipic acid.

[0070] The polyol may be aliphatic or may contain one or more aromatic rings, preferably the polyol is aliphatic.

[0071] The polyol may be selected from ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol (propylene glycol), 1,3-propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 3-ethyl-2-methyl-1,5-pentanediol, 2-ethyl-3-propyl-1,5-pentanediol, 2,4-dimethyl-3-ethyl-1,5-pentanediol, 2-ethyl-4-methyl-3-propyl-1,5-pentanediol, 2,3-diethyl-4-methyl-1,5-pentanediol, 3-ethyl-2,2,4-trimethyl-1,5-pentanediol, 2,2-dimethyl-4-ethyl-3-propyl-1 ,5-pentanediol, 2-methyl-2-propyl-1,5-pentanediol, 2,4-dimethyl-3-ethyl-2-propyl-1,5-pentanediol, 2,3-dipropyl-4-ethyl-2-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,5-pentanediol, 2-butyl-2,3-diethyl-4-methyl-1,5-pentanediol, 2-butyl-2,4-diethyl-3-propyl-1,5-pentanediol, 3-butyl-2-propyl-1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-pentanediol, 2,2-dimethyl-1,5-pentanediol, 3,3-dimethyl-1,5-pentanediol, 2,3-dimethyl-1, 5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-benzyloxy-1,3-propanediol, 2,2-dibenzyl-1,3-propanediol, 2,2-dibutyl-1,3-propanediol, 2,2-diisobutyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,6-hexanediol, 2,5-dimethyl-1,6-hexanediol, 5-methyl-2-(1-methylethyl)-1,3-hexanediol, 1,4-dimethyl-1,4-butanediol, 1,5-hexanediol, 3-methyl-1,6-hexanediol, 3-tert-butyl-1,6-hexanediol, 1,3-heptanediol, 1,2-octanediol, 1,3-octanediol, 2,2,7,7-tetramethyl-1,8-octanediol, 2-methyl-1,8-octanediol, 2,6-dimethyl-1,8-octanediol, 1,7-octanediol, 4,4,5,5-tetramethyl-3,6-dioxa-1,8-octanediol, 2,2,8,8-tetramethyl-1,9-nonanediol, 1,2-nonanediol, 2,8-dimethyl-1,9-nonanediol, 1,5-nonanediol, 2,9-dimethyl-2,9-dipropyl-1,10-decanediol, 2,9-dibutyl-2,9-dimethyl-1,10-decanediol, 2,9-dimethyl-2,9-dipropyl-1,10-decanediol, 2,9-diethyl-2,9-dimethyl-1,10-decanediol, 2,2,9,9-tetramethyl-1,10-decanediol, 2-nonyl-1,10-decanediol, 1,9-decanediol, 2,2,6,6,10,10-hexamethyl-4,8-dioxa-1,11-undecanediol, 2-octyl-1,11-undecanediol, 2,10-diethyl-2,10-dimethyl-1,11-undecanediol, 2,2,10,10-tetramethyl-1,11-undecanediol, 1-phenyl-1,11-undecanediol, 1,2-undecanediol, 1,2-dodecanediol, 2,11-dodecanediol, 2,11-diethyl- 2,11-dimethyl-1,12-dodecanediol, 2,11-dimethyl-2,11-dipropyl-1,12-dodecanediol, 2,11-dibutyl-2,11-dimethyl-1,12-dodecanediol, 2,2,11,11-tetramethyl-1,12-dodecanediol, 1,11-dodecanediol, 11-methyl-1,7-dodecanediol, 1,4-dodecanediol, 1,3-dodecanediol, 1,10-dodecanediol, 2,11-dimethyl-2,11-dodecanediol, 1,5-dodecanediol, 6,7-dodecanediol, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and mixtures thereof.

[0072] Advantageously, the polyol is selected from ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, bisphenol A, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and mixtures thereof.

[0073] Preferably, the polyol is selected from ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, and mixtures thereof.

[0074] More preferably, the polyol is selected from ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and mixtures thereof, especially 1,4-butanediol.

[0075] According to an embodiment, the crystalline polyester polyol in component A is obtained by reacting:

[0076] - a polycarboxylic acid selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, fumaric acid or its dimer, maleic acid or its dimer, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, phthalic acid, terephthalic acid, their ester-forming derivatives, and mixtures thereof, and

[0077] - a polyol selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, bisphenol A, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and mixtures thereof.

[0078] Preferably, the crystalline polyester polyol in component A is obtained by reacting:

[0079] - a polycarboxylic acid selected from the group consisting of adipic acid, suberic acid, sebacic acid, 1,12-dodecanedioic acid, their ester-forming derivatives, and mixtures thereof, and

[0080] - a polyol selected from the group consisting of ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and mixtures thereof.

[0081] More preferably, the crystalline polyester polyol in component A is obtained by reacting adipic acid (or an ester-forming derivative thereof) and 1,4-butanediol.

[0082] Advantageously, the crystalline polyester polyol in component A has a number average molecular weight of from 400 g / mol to 2500 g / mol, preferably from 500 g / mol to 2200 g / mol, more preferably from about 700 g / mol to about 2000 g / mol.

[0083] The number average molecular weight can be measured by size exclusion chromatography (or SEC), also referred to by the term "gel permeation chromatography" (or GPC), preferably calibrated with polystyrene.

[0084] The crystalline polyester polyol in component A may have a functionality comprised between 2 and 4, preferably between 2 and 3, more preferably 2; the "functionality" of the crystalline polyester polyol means the number (or average number) of hydroxyl groups per molecule of the crystalline polyester polyol. The functionality (f) may be determined by measuring the number average molecular weight (Mn) and hydroxyl (OH) value of the crystalline polyester polyol according to the formula: f=(Mn*OH value) / (56.1*1000), wherein Mn is in g / mol and OH value is in mg KOH / g.

[0085] The crystalline polyester polyol used in component A may have a hydroxyl value comprised between 45 and 300 mg KOH / g (milligrams of KOH per gram of crystalline polyester polyol), and preferably from 50 to 200 mg KOH / g. The hydroxyl value is preferably measured according to ISO 14900-17 (method A).

[0086] The crystalline polyester polyol in component A can be obtained by reacting at least one polyol with at least one polycarboxylic acid (or its ester-forming derivative) as described above, preferably in the presence of a catalyst (e.g. a titanium-based or zinc-based catalyst, such as tetra-n-butyl titanate), and heating at a temperature ranging up to 250° C., preferably ranging from 120° C. to 240° C., to eliminate the water formed (or the alcohol obtained from the transesterification if the ester-forming derivative is carried out). When most of the water has been eliminated (such as at least 95% of the theoretical amount), the pressure is reduced to less than 95 kPa, preferably between about 80 kPa and about 90 kPa. The reaction is preferably stopped when the acid value is less than 2 mg KOH / g (milligrams of KOH per gram of reaction mixture).

[0087] The acid value can be measured according to ISO 2114-2000 (Method A).

[0088] In order to obtain the reaction product, the content of the crystalline polyester polyol implemented in component A can vary from 1 to 40 dry weight%, preferably from 2 to 20 dry weight%, more preferably from 5 to 15 dry weight%, such as about 9 dry weight%, relative to the total dry weight of component A.

[0089] "About X" is intended to be more than 10% of the value of X or less than 10% of the value of X.

[0090] Polyether polyol in component A

[0091] Advantageously, the reaction product in component A is obtained by reacting an aliphatic polyisocyanate and a crystalline polyester polyol at least also with a polyether polyol.

[0092] "Polyether polyol" is intended to be a polymer comprising at least two hydroxyl (-OH) groups and at least two ether groups, the polymer comprising at least three repeating units. Preferably, the polyether polyol comprises a backbone comprising ether linkages and terminal ends comprising hydroxyl groups. More preferably, the polyether polyol comprises secondary hydroxyl groups, i.e. hydroxyl groups bonded to carbon atoms having exactly two substituents other than hydrogen atoms (and in addition to said hydroxyl groups).

[0093] The polyether polyols in component A are obtainable by polymerization of one or more epoxides. Such epoxides may be ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide and / or epichlorohydrin.

[0094] Thus, the polyether polyol may be selected from polyethylene glycol, polypropylene glycol, polybutylene oxide, poly(tetramethylene ether) glycol (PTMEG), poly(styrene oxide), poly(epichlorohydrin), and copolymers thereof such as block copolymers of polyethylene glycol and polypropylene glycol.

[0095] Advantageously, the polyether polyol is selected from polyethylene glycol, polypropylene glycol, PTMEG, and copolymers thereof such as block copolymers of polyethylene glycol and polypropylene glycol.

[0096] Preferably, the polyether polyol is selected from polyethylene glycol and polypropylene glycol.

[0097] More preferably, the polyether polyol is polypropylene glycol.

[0098] The polyether polyol in component A may have a number average molecular weight of from 250 g / mol to 2500 g / mol, preferably from 300 g / mol to 2000 g / mol, more preferably from about 400 g / mol to about 1000 g / mol, such as about 400 g / mol.

[0099] Additionally, the polyether polyol in component A may have a functionality comprised between 2 and 4, preferably between 2 and 3, more preferably 2; the “functionality” of the polyether polyol means the number (or average number) of hydroxyl groups per molecule of the polyether polyol.

[0100] To obtain the reaction product, the content of polyether polyol implemented in component A can vary from 5 to 50 % by dry weight, preferably from 15 to 40 % by dry weight, more preferably from 20 to 35 % by dry weight, relative to the total dry weight of component A.

[0101] Low molecular weight polyol in component A

[0102] Advantageously, the reaction product in component A is obtained by reacting an aliphatic polyisocyanate and a crystalline polyester polyol at least also with a low molecular weight polyol.

[0103] "Low molecular weight polyol" means a polyol other than the crystalline polyester polyols and polyether polyols described above and having a molecular weight below 300 g / mol. In particular, the low molecular weight polyol does not contain more than two repeating units.

[0104] Advantageously, the low molecular weight polyol has a molecular weight comprised between 50 and 250 g / mol, preferably between 60 and 200 g / mol, more preferably between 80 and 200 g / mol.

[0105] The low molecular weight polyol may be selected from 1,4-butanediol, ethylene glycol, diethylene glycol, 1,6-hexanediol, 1,2,3-propanetriol, trimethylolethane, trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, diethanolamine, and mixtures thereof.

[0106] Advantageously, the low molecular weight polyol is selected from 1,4-butanediol, ethylene glycol, diethylene glycol, 1,6-hexanediol, and mixtures thereof, in particular 1,4-butanediol.

[0107] The low molecular weight polyol in component A may have a functionality comprised between 2 and 4, preferably between 2 and 3, more preferably 2; the "functionality" of the low molecular weight polyol means the number of hydroxyl groups per molecule of the low molecular weight polyol.

[0108] To obtain the reaction product, the content of low molecular weight polyol implemented in component A can vary from 0.1 to 15 % by dry weight, preferably from 0.5 to 10 % by dry weight, more preferably from 0.5 to 5 % by dry weight, relative to the total dry weight of component A.

[0109] Silane coupling agent in component A

[0110] Advantageously, component A further comprises a silane coupling agent. Preferably, the silane coupling agent is used to obtain the reaction product in component A by reacting the aliphatic polyisocyanate and the crystalline polyester polyol at least with the silane coupling agent. Silane coupling agents are well known to those skilled in the art and are generally used as adhesion promoters.

[0111] "Silane coupling agent" is intended to be a compound containing at least one alkoxysilane group (silicon atom attached to at least one alkoxy group), wherein the silicon atom is attached to a hydrocarbon group which may contain one or more heteroatoms. Preferably, the silane coupling agent implemented in component A is not an epoxysilane compound, such as (3-glycidyloxypropyl)trimethoxysilane (GLYMO).

[0112] The silane coupling agent in component A may contain between 1 and 5 alkoxysilane groups, preferably one or two alkoxysilane groups. Each silicon atom is connected to at least one alkoxy group, preferably at least 2 alkoxy groups, more preferably 3 alkoxy groups. The alkoxy group may contain from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, more preferably it may be selected from methoxy groups and ethoxy groups.

[0113] Advantageously, the silane coupling agent in component A is an aminosilane compound. Such compounds are particularly useful for obtaining the reaction product in component A.

[0114] "Aminosilane compound" means a compound containing at least one alkoxysilane group, in which the silicon atom is connected to at least one amino group via a hydrocarbon chain. The amino group should have at least one hydrogen atom. Therefore, the amino group is a primary amino group or a secondary amino group in component A, preferably a secondary amino group.

[0115] Additionally, the aminosilane compound may contain between 1 and 5 amino groups, preferably one or two amino groups. In the event that more than one amino group is present on the aminosilane compound, one amino group may be, for example, a primary amine while another amino group may be a secondary amine.

[0116] The amino group is connected to the silicon atom via a hydrocarbon chain. The hydrocarbon chain may contain from 1 to 20 carbon atoms, preferably from 2 to 10 carbon atoms. One or more amino groups may be part of the hydrocarbon chain (two of the amine substituents are part of the hydrocarbon chain) and / or may be the terminal group (terminus) of the hydrocarbon chain.

[0117] According to an embodiment, the silane coupling agent in component A is selected from 1,2-bis(triethoxysilyl)ethane, n-octyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, (3-aminopropyl)triethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, bis(3-(triethoxysilyl)propyl)amine, bis(trimethoxysilylpropyl)amine, (3-aminopropyl)trimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, and mixtures thereof.

[0118] Preferably, the silane coupling agent in component A is selected from 3-aminopropylmethyldiethoxysilane, (3-aminopropyl)triethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, bis(3-(triethoxysilyl)propyl)amine, bis(trimethoxysilylpropyl)amine, (3-aminopropyl)trimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, and mixtures thereof.

[0119] More preferably, the silane coupling agent in component A is selected from bis(3-(triethoxysilyl)propyl)amine, bis(trimethoxysilylpropyl)amine, and mixtures thereof, especially bis(trimethoxysilylpropyl)amine.

[0120] In particular, in order to obtain a reaction product, the content of the silane coupling agent implemented in component A can vary from 0.01 to 5 wt. %, preferably from 0.1 to 3 wt. %, more preferably from 0.5 to 2 wt. %, relative to the total dry weight of component A.

[0121] Other characteristics of component A

[0122] Component A may further comprise one or more additives. Such additives may be selected from catalysts, fillers, plasticizers, tackifying resins, UV stabilizers, moisture absorbers, rheological additives, and mixtures thereof. These additives may be introduced into component A before, simultaneously with, or after obtaining the reaction product in component A. In particular, it is preferred to add a catalyst before or simultaneously with the ingredients implemented to obtain the reaction product in component A.

[0123] The catalyst may be selected from tetra-n-butyl titanate, titanium glycolate, antimony trioxide, tetraisopropyl titanate, and zinc acetate, preferably tetra-n-butyl titanate.

[0124] When a catalyst is added to component A, the catalyst content in component A may vary from 0.01 dry weight % to 0.05 dry weight % relative to the total dry weight of component A.

[0125] The total content of additives in component A may range up to 10% by dry weight, preferably up to 5% by dry weight, more preferably up to 2% by dry weight, relative to the total dry weight of component A.

[0126] Component A may further comprise a solvent, but component A preferably contains no solvent.

[0127] The "solvent" is intended to be a solvent used in the field of adhesives, in particular water, ethanol, isopropanol, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, cyclohexane, benzene, toluene, xylene and the like.

[0128] According to a preferred embodiment, the reaction product in component A is obtained by reacting aliphatic polyisocyanate and crystalline polyester polyol with polyether polyol and / or low molecular weight polyol, preferably at least with polyether polyol, more preferably with polyether polyol and low molecular weight polyol.

[0129] According to an embodiment, component A comprises:

[0130] - a reaction product obtained by reacting:

[0131] - from 30 to 90% by dry weight of aliphatic polyisocyanates,

[0132] - from 1 to 40% by dry weight of a crystalline polyester polyol having a number average molecular weight of less than 3000 g / mol,

[0133] - from 5 to 50% by dry weight of polyether polyols, and

[0134] - from 0.1 to 15% by dry weight of low molecular weight polyols,

[0135] - optionally from 0.01 to 5% by dry weight of a silane coupling agent, and

[0136] - up to 10% by dry weight of one or more additives selected from catalysts, fillers, plasticizers, tackifying resins, UV stabilizers, moisture absorbers, rheological additives, and mixtures thereof,

[0137] The percentages are relative to the total dry weight of component A.

[0138] Advantageously, a silane coupling agent is used to obtain the reaction product in component A.

[0139] Preferably, component A consists essentially of the above ingredients. "Essentially consisting of..." is intended to mean that component A contains less than 5% by dry weight, preferably less than 2% by dry weight, more preferably less than 1% by dry weight of ingredients other than the above ingredients, relative to the total dry weight of component A.

[0140] The ingredients of this embodiment and their specific contents, including this embodiment, are as described above.

[0141] According to a specific embodiment, component A comprises:

[0142] - a reaction product obtained by reacting:

[0143] - from 50 to 70% by dry weight of an aliphatic polyisocyanate, preferably selected from isophorone diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, 1,4-cyclohexylene diisocyanate, 2,4-diisocyanato-1-methylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, and mixtures thereof,

[0144] - from 5 to 15% by dry weight of a crystalline polyester polyol having a number average molecular weight of less than 3000 g / mol, preferably obtained by reacting:

[0145] - a polycarboxylic acid selected from the group consisting of adipic acid, suberic acid, sebacic acid, 1,12-dodecanedioic acid, their ester-forming derivatives, and mixtures thereof, and

[0146] - a polyol selected from the group consisting of ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and mixtures thereof,

[0147] - from 20 to 35% by dry weight of a polyether polyol, preferably selected from polyethylene glycol, polypropylene glycol, PTMEG, and copolymers thereof, and

[0148] - from 0.5 to 5% by dry weight of a low molecular weight polyol, preferably selected from 1,4-butanediol, ethylene glycol, diethylene glycol, 1,6-hexanediol, and mixtures thereof,

[0149] - optionally from 0.5 to 2% by dry weight of a silane coupling agent, preferably an aminosilane compound, which is preferably used to obtain the reaction product, and

[0150] - up to 2% by dry weight of one or more additives selected from catalysts, fillers, plasticizers, tackifying resins, UV stabilizers, moisture absorbers, rheological additives, and mixtures thereof,

[0151] The percentages are relative to the total dry weight of component A.

[0152] Preferably, component A consists essentially of the above ingredients.

[0153] The ingredients of this embodiment and their specific contents, including this embodiment, are as described above.

[0154] To produce component A, the compounds mentioned above may be mixed together, preferably under an inert atmosphere such as nitrogen.

[0155] According to a preferred embodiment, aliphatic polyisocyanate can be first mixed with crystalline polyester polyol and optionally polyether polyol and / or low molecular weight polyol. At this time, the hydroxyl group of crystalline polyester polyol, polyether polyol and / or low molecular weight polyol can react with the isocyanate group of polyisocyanate compound to form a polyurethane prepolymer containing isocyanate terminal. Then, silane coupling agent can be optionally added to the mixture. For example, before adding silane coupling agent, aliphatic polyisocyanate can be mixed with crystalline polyester polyol and optionally polyether polyol and / or low molecular weight polyol for a period of time between 30 minutes and 4 hours, preferably between 1.5 and 3.5 hours.

[0156] The catalyst can be added to component A when the aliphatic polyisocyanate is mixed with the crystalline polyester polyol and optionally the polyether polyol and / or the low molecular weight polyol, or after this step.

[0157] Additionally, in the case of conducting a polyether polyol and / or a low molecular weight polyol with a crystalline polyester polyol to form the reaction product in component A, the polyols may be mixed together before adding the aliphatic polyisocyanate.

[0158] The amounts of aliphatic polyisocyanate and one or more polyols implemented to obtain the reaction product in component A may be such that the -NCO / -OH molar equivalent ratio may be greater than or equal to 1.3, advantageously greater than or equal to 1.5, preferably greater than or equal to 2.0, more preferably greater than or equal to 2.5. For example, the -NCO / -OH molar equivalent ratio may be comprised between 1.3 and 10, advantageously between 1.5 and 5, preferably between 2.0 and 4, more preferably between 2.5 and 3.5.

[0159] The -NCO / -OH molar equivalent ratio is defined as the molar equivalent number of -NCO groups of the aliphatic polyisocyanate divided by the sum of the molar equivalent number of -OH groups of each polyol. The molar equivalent number of -NCO groups of the aliphatic polyisocyanate is equal to: f(-NCO)*(m 多异氰酸酯 / M 多异氰酸酯 ), where f(-NCO) is the number of -NCO groups of the aliphatic polyisocyanate, m 多异氰酸酯 is the mass of aliphatic polyisocyanate introduced in g, and M 多异氰酸酯 is the molar mass of the aliphatic polyisocyanate in g / mol. The number of molar equivalents of -OH groups of the polyol is equal to: f(-OH)*(m 多元醇 / M 多元醇 ), where f(-OH) is the number of -OH groups in the polyol, m 多元醇 is the mass of polyol introduced in g, and M 多元醇 is the molar mass of the polyol in g / mol (or when the polyol is a polymer, its number average molecular weight).

[0160] The reaction with the aliphatic polyisocyanate may be carried out at a temperature of from 40°C to 100°C, preferably from 50°C to 90°C. The temperature may remain stable during the mixing of the different compounds implemented in component A, or may vary during the mixing of the different compounds implemented in component A. According to an embodiment in which a polyether polyol and / or a low molecular weight polyol is implemented with a crystalline polyester polyol to form a reaction product in component A, the polyols may be mixed together at a temperature of from 40°C to 65°C, and after the addition of the polyisocyanate compound, the temperature may be raised to from 70°C to 90°C. Prior to the mixing of component A with component B, the temperature of component A is preferably cooled at a temperature of less than or equal to 50°C.

[0161] Component A can have an NCO content comprised between 5% and 40% by weight, preferably between 10% and 30% by weight, more preferably between 10% and 20% by weight, based on the total weight of component A.

[0162] The NCO content of component A can be measured according to standard ASTM D2572 (2010).

[0163] Component A may also have a viscosity comprised between 1000 and 15000 mPa.s, preferably between 1500 and 10000 mPa.s, more preferably between 2000 and 5000 mPa.s at 40° C. The viscosity may be measured using a Brookfield LVT viscometer and using standard EN ISO 2555 (2018).

[0164] Component B

[0165] Polyester polyol in component B

[0166] "Polyester polyol" is intended to be a polymer comprising at least two hydroxyl (-OH) groups and at least two ester groups. Preferably, the polyester polyol comprises a backbone comprising ester linkages and terminal ends comprising hydroxyl groups. More preferably, the polyester polyol comprises primary hydroxyl groups, i.e., hydroxyl groups bonded to carbon atoms having exactly one substituent other than a hydrogen atom (and in addition to said hydroxyl groups).

[0167] The polyester polyol in component B may be as described above for the crystalline polyester polyol in component A. However, the polyester polyol present in component B is preferably different from the crystalline polyester polyol present in component A, in particular the polyester polyol in component B is preferably non-crystalline.

[0168] The polyester polyols in component B are obtainable by reacting at least one polyol with at least one polycarboxylic acid or an ester-forming derivative thereof, and optionally with at least one fatty acid and / or one or more triglycerides thereof, the ester-forming derivatives (such as anhydrides or halides thereof) being capable of forming ester bonds after reaction with hydroxyl groups.

[0169] The molar ratio of the at least one polyol relative to the at least one polycarboxylic acid may vary from 1 to 2, preferably from 1.05 to 2.0, more preferably from 1.2 to 1.8, even more preferably from 1.3 to 1.7.

[0170] When the polyester polyol in component B is obtained from at least one fatty acid and / or one or more triglycerides thereof, the molar ratio of the at least one polyol relative to the at least one fatty acid and / or one or more triglycerides thereof may vary from 1 to 2, preferably from 1.05 to 2.0, more preferably from 1.2 to 1.8, even more preferably from 1.3 to 1.7.

[0171] The polycarboxylic acids may be aliphatic or may contain one or more aromatic rings.

[0172] Advantageously, the polycarboxylic acid is selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, fumaric acid or a dimer thereof, maleic acid or a dimer thereof, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, phthalic acid, terephthalic acid, ester-forming derivatives thereof, and mixtures thereof.

[0173] Preferably, the polycarboxylic acid is selected from succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, isophthalic acid, phthalic acid, terephthalic acid, ester-forming derivatives thereof, and mixtures thereof.

[0174] More preferably, the polycarboxylic acid is selected from glutaric acid, adipic acid, pimelic acid, azelaic acid, isophthalic acid, phthalic acid, terephthalic acid, ester-forming derivatives thereof, and mixtures thereof, in particular adipic acid and / or isophthalic acid.

[0175] The polyol may be aliphatic or may contain one or more aromatic rings, preferably the polyol is aliphatic.The polyol is not a fatty acid or a triglyceride thereof.

[0176] The polyol may be selected from ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol (propylene glycol), 1,3-propylene glycol, trimethylolpropane, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 3-ethyl-2-methyl-1,5-pentanediol, 2-ethyl-3-propyl-1,5-pentanediol, 2,4-dimethyl-3-ethyl-1,5-pentanediol, 2-ethyl-4-methyl-3-propyl-1,5-pentanediol, 2,3-diethyl-4-methyl-1,5-pentanediol, 3-ethyl-2,2,4-trimethyl-1,5-pentanediol, 2,2-dimethyl-4-ethyl -3-propyl-1,5-pentanediol, 2-methyl-2-propyl-1,5-pentanediol, 2,4-dimethyl-3-ethyl-2-propyl-1,5-pentanediol, 2,3-dipropyl-4-ethyl-2-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,5-pentanediol, 2-butyl-2,3-diethyl-4-methyl-1,5-pentanediol, 2-butyl-2,4-diethyl-3-propyl-1,5-pentanediol, 3-butyl-2-propyl-1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,2-dimethyl-1,3-pentanediol, 2,2-dimethyl-1,5-pentanediol, 3,3-dimethyl-1,5-pentanediol, 2,3 -Dimethyl-1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-benzyloxy-1,3-propanediol, 2,2-dibenzyl-1,3-propanediol, 2,2-dibutyl-1,3-propanediol, 2,2-diisobutyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,6-hexanediol, 2,5-dimethyl-1,6-hexanediol, 5-methyl-2-(1-methylethyl)-1,3-hexanediol, 1,4-dimethyl-1,4-butanediol, 1,5-Hexanediol, 3-methyl-1,6-hexanediol, 3-tert-butyl-1,6-hexanediol, 1,3-heptanediol, 1,2-octanediol, 1,3-octanediol, 2,2,7,7-tetramethyl-1,8-octanediol, 2-methyl-1,8-octanediol, 2,6-dimethyl-1,8-octanediol, 1,7-octanediol, 4,4,5,5-tetramethyl-3,6-dioxa-1,8-octanediol, 2,2,8,8-tetramethyl-1,9-nonanediol, 1,2-nonanediol, 2,8-dimethyl-1,9-nonanediol, 1,5-nonanediol, 2,9-dimethyl-2,9-dipropyl-1,10-decanediol, 2,9-dibutyl-2,9-dimethyl-1,10-decanediol, 2,9-dimethyl-2,9-dipropyl-1,10-decanediol, 2,9-diethyl-2,9-dimethyl-1,10-decanediol, 2,2,9,9-tetramethyl-1,10-decanediol, 2-nonyl-1,10-decanediol, 1,9-decanediol, 2,2,6,6,10,10-hexamethyl-4,8-dioxa-1,11-undecanediol, 2-octyl-1,11-undecanediol, 2,10-diethyl-2,10-dimethyl-1,11-undecanediol, 2,2,10,10-tetramethyl-1,11-undecanediol, 1-phenyl-1,11-undecanediol, 1,2-undecanediol, 1,2-dodecanediol, 2,11-dodecanediol, 2,11- Diethyl-2,11-dimethyl-1,12-dodecanediol, 2,11-dimethyl-2,11-dipropyl-1,12-dodecanediol, 2,11-dibutyl-2,11-dimethyl-1,12-dodecanediol, 2,2,11,11-tetramethyl-1,12-dodecanediol, 1,11-dodecanediol, 11-methyl-1,7-dodecanediol, 1,4-dodecanediol, 1,3-dodecanediol, 1,10-dodecanediol, 2,11-dimethyl-2,11-dodecanediol, 1,5-dodecanediol, 6,7-dodecanediol, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and mixtures thereof.

[0177] Advantageously, the polyol is selected from ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, trimethylolpropane, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, bisphenol A, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and mixtures thereof.

[0178] Preferably, the polyol is selected from ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, trimethylolpropane, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanediol, and mixtures thereof.

[0179] More preferably, the polyol is selected from ethylene glycol, diethylene glycol, propylene glycol, trimethylolpropane, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and mixtures thereof, in particular diethylene glycol and / or trimethylolpropane.

[0180] "Fatty acid" is intended to be a compound having an aliphatic chain, which may contain one or more double bonds and / or one or more hydroxyl groups, as well as a carboxylic acid group (-C(O)OH). In particular, the fatty acid contains between 4 and 28 carbon atoms, preferably between 10 and 22 carbon atoms, more preferably between 16 and 20 carbon atoms such as 18 carbon atoms.

[0181] Preferably, the at least one fatty acid comprises a fatty acid containing one or more hydroxyl groups.

[0182] "Triglyceride" is intended to be a triester obtained from glycerol and three fatty acids, which may be the same or different.

[0183] At least one fatty acid and / or one or more triglycerides thereof preferably comprise one or more triglycerides of the at least one fatty acid, wherein the at least one fatty acid preferably comprises a fatty acid containing one or more hydroxyl groups. In particular, at least one fatty acid and / or one or more triglycerides thereof can be provided in the form of a vegetable oil such as castor oil.

[0184] Advantageously, at least one fatty acid and / or one or more triglycerides thereof comprise ricinoleic acid, preferably at least one fatty acid and / or one or more triglycerides thereof comprise ricinoleic acid. In particular, at least one fatty acid and / or one or more triglycerides thereof may be provided in the form of castor oil.

[0185] The at least one fatty acid and / or the one or more triglycerides thereof may further comprise oleic acid, linoleic acid, α-linoleic acid, palmitic acid and / or stearic acid, preferably oleic acid and / or linoleic acid.

[0186] According to a preferred embodiment, at least one fatty acid and / or its one or more triglycerides comprise a mixture of a fatty acid and / or a mixture of triglycerides of a mixture of a fatty acid. Preferably, at least one fatty acid and / or its one or more triglycerides comprise a mixture containing ricinoleic acid, oleic acid and linoleic acid, and / or a mixture of triglycerides containing ricinoleic acid, oleic acid and linoleic fatty acids. More preferably, at least one fatty acid and / or its one or more triglycerides comprise a mixture of triglycerides containing ricinoleic acid, oleic acid and linoleic fatty acids.

[0187] In particular, the at least one fatty acid and / or one or more triglycerides thereof may be provided in the form of castor oil.

[0188] According to an embodiment, the polyester polyol in component B is obtained by reacting:

[0189] - a polycarboxylic acid selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, fumaric acid or its dimer, maleic acid or its dimer, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, phthalic acid, terephthalic acid, their ester-forming derivatives, and mixtures thereof, and

[0190] - a polyol selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propylene glycol, trimethylolpropane, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, bisphenol A, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and mixtures thereof,

[0191] - optionally with at least one fatty acid comprising a fatty acid containing one or more hydroxyl groups and / or one or more triglycerides thereof.

[0192] Preferably, the polyester polyol in component B is obtained by reacting:

[0193] - a polycarboxylic acid selected from the group consisting of glutaric acid, adipic acid, pimelic acid, azelaic acid, isophthalic acid, phthalic acid, terephthalic acid, their ester-forming derivatives, and mixtures thereof, and

[0194] - a polyol selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, trimethylolpropane, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and mixtures thereof,

[0195] - optionally with at least one fatty acid comprising ricinoleic acid and / or one or more triglycerides thereof.

[0196] More preferably, the polyester polyol in component B is obtained by reacting adipic acid and / or isophthalic acid (or its ester-forming derivatives), and diethylene glycol and / or trimethylolpropane, optionally with at least one fatty acid comprising ricinoleic acid (which can be provided in the form of castor oil) and / or one or more triglycerides thereof.

[0197] The polyester polyols present in component B may have a number average molecular weight of from 400 g / mol to 2000 g / mol, preferably from 500 g / mol to 1000 g / mol.

[0198] The polyester polyol in component B may have a functionality comprised between 2 and 4, preferably between 2 and 3, more preferably between 2.0 and 2.7; the "functionality" of the polyester polyol means the number (or average number) of hydroxyl groups per molecule of the polyester polyol.

[0199] The total polyester polyol content in component B may vary from 60 to 98 % by dry weight, preferably from 70 to 95 % by dry weight, more preferably from 85 to 95 % by dry weight, relative to the total dry weight of component B.

[0200] Preferably, component B does not comprise any polyether polyols.

[0201] The polyester polyol in component B may be obtained as described above for the crystalline polyester polyol in component A (with the optional addition of at least one fatty acid and / or one or more triglycerides thereof at the same time as the polyol and the polycarboxylic acid).

[0202] According to an embodiment, component B comprises at least two polyester polyols, preferably exactly two polyester polyols.

[0203] According to this embodiment, preferably at least one polyester polyol is obtained from at least one fatty acid and / or one or more triglycerides thereof, and at least one polyester polyol is not obtained from any fatty acid and / or one or more triglycerides thereof. In this case, at least one fatty acid and / or one or more triglycerides thereof comprise ricinoleic acid, preferably one or more triglycerides of at least one fatty acid of ricinoleic acid.

[0204] Furthermore, according to this embodiment, preferably at least one polyester polyol is obtained from an aromatic polycarboxylic acid and at least one polyester polyol is obtained from an aliphatic polycarboxylic acid. In this case, the aromatic polycarboxylic acid is preferably selected from isophthalic acid, phthalic acid, terephthalic acid, ester-forming derivatives thereof, and mixtures thereof, in particular isophthalic acid, and the aliphatic polycarboxylic acid is preferably selected from glutaric acid, adipic acid, pimelic acid, azelaic acid, ester-forming derivatives thereof, and mixtures thereof, in particular adipic acid.

[0205] According to this embodiment, preferably at least two polyester polyols are obtained from the following polyols: ethylene glycol, diethylene glycol, propylene glycol, trimethylolpropane, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and mixtures thereof, in particular at least one polyester polyol is obtained from diethylene glycol, and at least one polyester polyol is obtained from diethylene glycol and trimethylolpropane.

[0206] More preferably, according to this embodiment:

[0207] - at least one polyester polyol obtained from:

[0208] at least one fatty acid comprising ricinoleic acid (which may be provided in the form of castor oil) and / or one or more triglycerides thereof,

[0209] - an aromatic polycarboxylic acid preferably selected from the group consisting of isophthalic acid, phthalic acid, terephthalic acid, their ester-forming derivatives, and mixtures thereof, in particular isophthalic acid, and

[0210] - a polyol selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, trimethylolpropane, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and mixtures thereof, in particular diethylene glycol, and

[0211] - at least one polyester polyol is not obtained from fatty acids but is obtained from:

[0212] - an aliphatic polycarboxylic acid preferably selected from the group consisting of glutaric acid, adipic acid, pimelic acid, azelaic acid, their ester-forming derivatives, and mixtures thereof, in particular adipic acid, and

[0213] - a polyol selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, trimethylolpropane, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and mixtures thereof, in particular diethylene glycol and trimethylolpropane,

[0214] The weight ratio of the polyester polyol obtained from at least one fatty acid relative to the polyester polyol not obtained from fatty acids is preferably comprised between 0.5 and 3, more preferably between 1.0 and 2.5 such as about 2.

[0215] According to this embodiment, preferably at least two polyester polyols have different functionalities, which are preferably between 2 and 3.

[0216] Chain extender in component B

[0217] "Chain extender" means a compound comprising at least two, preferably at least three functional groups, which are hydroxyl and / or amine groups, and the one or more amine groups are one or more primary and / or secondary amine groups. Preferably, the chain extender comprises at least one hydroxyl group, more preferably at least two hydroxyl groups.

[0218] The chain extender in component B is different from the crystalline polyester polyol in component A, the polyester polyol in component B and the polyether polyol in component A as described above and has a molecular weight below 300 g / mol. In particular, the chain extender does not contain more than two repeating units.

[0219] Advantageously, the chain extender in component B has a molecular weight comprised between 50 and 290 g / mol, preferably between 60 and 200 g / mol, more preferably between 80 and 200 g / mol.

[0220] The chain extender in component B may be selected from 1,4-butanediol, ethylene glycol, diethylene glycol, 1,6-hexanediol, 1,2,3-propanetriol, trimethylolethane, trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, diethanolamine, ethanolamine, and mixtures thereof.

[0221] Advantageously, the chain extender in component B is selected from 1,2,3-propanetriol, trimethylolethane, trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, diethanolamine, ethanolamine, and mixtures thereof, in particular triethanolamine.

[0222] The content of the chain extender in component B may vary from 1 to 20 % by dry weight, preferably from 2 to 13 % by dry weight, more preferably from 5 to 10 % by dry weight, relative to the total dry weight of component B.

[0223] Silane coupling agent in component B

[0224] "Silane coupling agent" is intended to be a compound containing at least one alkoxysilane group (silicon atom connected to at least one alkoxy group), wherein the silicon atom is connected to a hydrocarbon group that may contain one or more heteroatoms. Preferably, the silane coupling agent in component B is not an epoxysilane compound such as (3-glycidyloxypropyl)trimethoxysilane (GLYMO).

[0225] The silane coupling agent in component B may contain between 1 and 5 alkoxysilane groups, preferably 1 or 2 alkoxysilane groups. Each silicon atom is connected to at least one alkoxy group, preferably at least 2 alkoxy groups, more preferably 3 alkoxy groups. The alkoxy group may contain from 1 to 10 carbon atoms, preferably from 1 to 5 carbon atoms, more preferably it may be selected from methoxy groups and ethoxy groups.

[0226] Advantageously, the silane coupling agent in component B is an aminosilane compound.

[0227] "Aminosilane compound" means a compound containing at least one alkoxysilane group, in which the silicon atom is connected to at least one amino group via a hydrocarbon chain. The amino group should have at least one hydrogen atom. Therefore, the amino group is a primary or secondary amine in component B, preferably a primary amine.

[0228] Additionally, the aminosilane compound may contain between 1 and 5 amino groups, preferably one or two amino groups. In the event that more than one amino group is present on the aminosilane compound, one amino group may be, for example, a primary amine while another amino group may be a secondary amine.

[0229] The amino group is connected to the silicon atom via a hydrocarbon chain. The hydrocarbon chain may contain from 1 to 20 carbon atoms, preferably from 2 to 10 carbon atoms. One or more amino groups may be part of the hydrocarbon chain (two of the amine substituents are part of the hydrocarbon chain) and / or may be the terminal group (terminus) of the hydrocarbon chain.

[0230] According to an embodiment, the silane coupling agent in component B is selected from 1,2-bis(triethoxysilyl)ethane, n-octyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, (3-aminopropyl)triethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, bis(3-(triethoxysilyl)propyl)amine, bis(trimethoxysilylpropyl)amine, (3-aminopropyl)trimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, and mixtures thereof.

[0231] Preferably, the silane coupling agent in component B is selected from 3-aminopropylmethyldiethoxysilane, (3-aminopropyl)triethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, bis(3-(triethoxysilyl)propyl)amine, bis(trimethoxysilylpropyl)amine, (3-aminopropyl)trimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, and mixtures thereof.

[0232] More preferably, the silane coupling agent in component B is selected from 3-aminopropylmethyldiethoxysilane, (3-aminopropyl)triethoxysilane, (3-aminopropyl)trimethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, and mixtures thereof, especially (3-aminopropyl)triethoxysilane.

[0233] When component A contains a silane coupling agent, the silane coupling agent in component B may be the same as or different from the silane coupling agent in component A. Preferably, the silane coupling agent in component B is different from the silane coupling agent in component A. More preferably, the silane coupling agent in component B is a primary amine and the silane coupling agent in component A is a secondary amine.

[0234] The silane coupling agent in component B may vary from 0.1 to 10 % by dry weight, preferably from 1 to 5 % by dry weight, more preferably from 2 to 4 % by dry weight, relative to the total dry weight of component B.

[0235] Other characteristics of component B

[0236] Component B may further comprise one or more additives. Such additives may be selected from catalysts, fillers, plasticizers, tackifying resins, UV stabilizers, moisture absorbers, rheological additives, and mixtures thereof.

[0237] The catalyst may be selected from tetra-n-butyl titanate, titanium glycolate, antimony trioxide, tetraisopropyl titanate, and zinc acetate, preferably tetra-n-butyl titanate.

[0238] When a catalyst is added to component B, the catalyst content in component B may vary from 0.01 dry weight % to 0.05 dry weight % relative to the total dry weight of component B.

[0239] The total content of additives in component B may range up to 10% by dry weight, preferably up to 5% by dry weight, more preferably up to 2% by dry weight, relative to the total dry weight of component B.

[0240] Component B may further comprise a solvent, but component B preferably contains no solvent.

[0241] The "solvent" is intended to be a solvent used in the field of adhesives, in particular water, ethanol, isopropanol, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, cyclohexane, benzene, toluene, xylene and the like.

[0242] According to an embodiment, component B comprises:

[0243] - from 60 to 98% by dry weight of at least one polyester polyol, preferably at least two polyester polyols,

[0244] - from 1 to 20% by dry weight of a chain extender,

[0245] - from 0.1 to 10% by dry weight of a silane coupling agent, and

[0246] - up to 10% by dry weight of one or more additives selected from catalysts, fillers, plasticizers, tackifying resins, UV stabilizers, moisture absorbers, rheological additives, and mixtures thereof,

[0247] The percentages are relative to the total dry weight of component B.

[0248] Preferably, component B consists essentially of the above ingredients. "Essentially consisting of..." is intended to mean that component B contains less than 5% by dry weight, preferably less than 2% by dry weight, more preferably less than 1% by dry weight of ingredients other than the above ingredients relative to the total dry weight of component B.

[0249] The ingredients of this embodiment and their specific contents, including this embodiment, are as described above.

[0250] According to a specific embodiment, component B comprises:

[0251] - from 85 to 95% by dry weight of at least one polyester polyol, preferably at least two polyester polyols, the one or more polyester polyols being preferably obtained by reacting:

[0252] - a polycarboxylic acid selected from the group consisting of glutaric acid, adipic acid, pimelic acid, azelaic acid, isophthalic acid, phthalic acid, terephthalic acid, their ester-forming derivatives, and mixtures thereof, and

[0253] - a polyol selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, trimethylolpropane, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and mixtures thereof,

[0254] - optionally with at least one fatty acid comprising ricinoleic acid (which may be provided in the form of castor oil) and / or one or more triglycerides thereof.

[0255] - from 2 to 13% by dry weight of a chain extender, preferably selected from 1,2,3-propanetriol, trimethylolethane, trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, diethanolamine, ethanolamine, and mixtures thereof,

[0256] - from 2 to 4% by dry weight of a silane coupling agent, preferably an aminosilane compound, and

[0257] - up to 2% by dry weight of one or more additives selected from catalysts, fillers, plasticizers, tackifying resins, UV stabilizers, moisture absorbers, rheological additives, and mixtures thereof,

[0258] The percentages are relative to the total dry weight of component B.

[0259] Preferably, component B consists essentially of the above ingredients.

[0260] The ingredients of this embodiment and their specific contents, including this embodiment, are as described above.

[0261] To produce component B, the compounds mentioned above may be mixed together, preferably under an inert atmosphere such as nitrogen.

[0262] According to a preferred embodiment, at least one polyester polyol may be first mixed with a chain extender. Then, a silane coupling agent may be added to the mixture. For example, before adding the silane coupling agent, at least one polyester polyol may be mixed with a chain extender for a period of time comprised between 10 minutes and 2 hours, preferably between 20 minutes and 1 hour.

[0263] During mixing, the temperature may vary from 30 to 80° C., preferably from 40 to 70° C. During mixing of the different compounds to obtain component B, the temperature may remain stable or may vary.

[0264] Component B may have a hydroxyl number per gram of composition B comprised between 50 and 500 mg KOH / g, preferably between 100 and 300 mg KOH / g, more preferably between 200 and 250 mg KOH / g.

[0265] The hydroxyl value of component B can be measured according to ISO 14900-17 (Method A).

[0266] Component B may also have a viscosity comprised between 1000 and 15000 mPa.s, preferably between 1500 and 10000 mPa.s, more preferably between 2000 and 5000 mPa.s at 25° C. The viscosity can be measured using a Brookfield LVT viscometer and using standard EN ISO 2555 (2018).

[0267] Preparation and characterization of two-component compositions

[0268] The two-component composition according to the present invention can be produced when component A is mixed with component B. When the two components are mixed, the hydroxyl groups of the at least one polyester polyol and chain extender present in component B can react with the isocyanate ends of the urethane prepolymer of component A to form a polyurethane adhesive.

[0269] The presence of one or more silane coupling agents in the two-component composition makes it possible to increase the adhesive strength of the composition to its substrate, since the alkoxy groups of the silane can react with the substrate on which the adhesive is applied.

[0270] The NCO:OH molar ratio (NCO molar content in component A to OH molar content in component B) in the two-component composition according to the invention can vary from 0.5 to 10, preferably from 1.0 to 5, more preferably from 1.0 to 3.

[0271] The two-component composition may have a pot life (effective period) comprised between 20 min and 40 min at 55° C. when component A is mixed with component B. The pot life corresponds to the time required for the composition (obtained after mixing components A and B) to reach a viscosity of 3000 cP (which can be measured using a Brookfield LVT viscometer and using standard EN ISO 2555 (2018)).

[0272] The two-component composition according to the invention may contain solvents, but is preferably solvent-free.

[0273] Advantageously, the two-component composition according to the invention contains no primary aromatic amines.

[0274] Furthermore, the two-component composition according to the invention is advantageously free of epoxysilane compounds such as (3-glycidyloxypropyl)trimethoxysilane (GLYMO).

[0275] Uses of two-component compositions

[0276] The two-component composition can be applied to the surface of a substrate. The substrate can be selected from paper, metals such as aluminum, and thermoplastic polymers such as:

[0277] - Polyethylene (PE),

[0278] - polypropylene (PP), in particular cast polypropylene (CPP) or retort cast polypropylene (RCPP),

[0279] - ethylene-based and propylene-based copolymers,

[0280] - polyamide (PA), especially nylon,

[0281] - Polyethylene terephthalate (PET),

[0282] - ethylene-based copolymers, such as, for example, maleic anhydride-grafted copolymers, copolymers of ethylene and vinyl acetate (EVA), copolymers of ethylene and vinyl alcohol (EVOH), or copolymers of ethylene and alkyl acrylates such as methyl acrylate (EMA) or butyl acrylate (EBA),

[0283] - Polystyrene (PS),

[0284] - Polyvinyl chloride (PVC),

[0285] - Polyvinylidene fluoride (PVDF),

[0286] - polymers or copolymers of lactic acid (PLA), or

[0287] - Polyhydroxyalkanoate (PHA).

[0288] When two substrates are implemented, they are preferably different.

[0289] Preferably, the substrate is selected from aluminum, PP and PA, more preferably selected from aluminum, RCPP and nylon.

[0290] According to an embodiment, one of the two components (A or B) can be applied to the surface of the substrate first, and then the second of the two components is applied to the surface of the substrate on top of the first component. In this case, the reaction between component A and component B occurs on the surface of the substrate.

[0291] According to a preferred embodiment, component A is mixed with component B before the two-component composition is applied on the surface of the substrate. In this case, component A can be mixed with component B at a temperature ranging from 40° C. to 70° C., preferably from 45° C. to 60° C. The composition applied on the surface of the substrate can then be applied at a temperature ranging from 40° C. to 70° C., preferably from 45° C. to 60° C., and curing can be achieved at a temperature ranging from 40° C. to 60° C. for a period of time comprised between 3 and 5 days.

[0292] In both cases, the two-component composition can form a layer on the surface of the substrate. This layer can correspond to less than 7 g / m 2 (i.e. every m 2 The substrate surface is less than 7 g of the two-component composition), preferably from 0.5 g / m 2 Up to 5 g / m 2 , more preferably from 1 g / m 2 Up to 4 g / m 2 The ratio of the amount.

[0293] According to a preferred embodiment, the two-component composition according to the present invention can be used as an adhesive composition to bond two substrates together. Therefore, after curing, the composition can form an adhesive layer that holds the two substrates together. More particularly, after applying the two-component composition on the surface of the substrate, the surface of the other substrate can be brought into contact with the coated surface to bond the two substrates.

[0294] In particular, when the two-component composition according to the invention is used as an adhesive composition, it can be implemented in a laminator.

[0295] According to another embodiment, the two-component composition according to the invention can be used as a coating on the surface of a substrate. Thus, after curing, the composition can form a layer covering the surface of the substrate, for example to change one or more properties of its surface.

[0296] The present invention therefore relates to articles, in particular multilayer films, comprising at least one surface coated with a two-component composition according to the invention.

[0297] When the two-component composition is used as a coating, it is the outer surface of the article.

[0298] When the two-component composition is used as an adhesive, it is the inner surface of the article, ie the surface of the article that is in contact with another surface of the article, for example, the two-component composition being located between the two surfaces.

[0299] Such an article can be obtained by a process comprising:

[0300] - applying the two-component composition according to the invention to at least one surface of a substrate,

[0301] - optionally contacting said surface with the surface of a further substrate, and

[0302] - Curing the two-component composition according to the invention.

[0303] The substrate is as described above.

[0304] After application and curing, the article comprising a layer made of the two-component composition of the invention may be subjected to a post-treatment, such as a sterilization post-treatment. This may include retorting or steam treatment. In particular, the article may be subjected to heating in the presence of water, for example at a temperature from 110 to 140° C., in particular at about 121° C., for a period of from 10 minutes to 2 hours, in particular from 30 min to 50 min, such as about 40 min. This may be carried out in an autoclave machine. The article may in particular be a multilayer film, which may be in the form of a pouch.

[0305] Therefore, the two-component composition according to the present invention can be used as an adhesive to produce an article, in particular a multilayer film, the adhesive having a bonding strength value greater than or equal to 3.5 N / 15 mm, preferably greater than or equal to 4.0 N / 15 mm, more preferably greater than or equal to 4.5 N / 15 mm after sterilization (e.g., at 121° C. for 40 min). The article is as described above. The bonding strength value can be measured according to GB / T 8808-1988 Test Method for Peel Force of Flexible Laminated Plastics, in particular as described in Example 1.

[0306] The invention also relates to a multilayer film comprising at least two substrate layers bonded together by a continuous layer, wherein the continuous layer consists of the two-component composition according to the invention, in particular in an amount of less than 7 g / m 2 (i.e. every m 2 The surface of the substrate is less than 7g of the two-component composition), preferably from 0.5 g / m 2 Up to 5 g / m 2 , more preferably from 1 g / m 2 Up to 4 g / m 2 The ratio of the amount.

[0307] The substrate surrounding the layer of the two-component composition is generally selected from the substrates mentioned above and is preferably different.

[0308] Preferably, the substrate surrounding the two-component combination layer is selected from aluminum, PP and PA, more preferably selected from aluminum, RCPP and nylon.

[0309] The thickness of the two substrate layers adjacent to the two-component composition layer and the other layers employed in the multilayer film according to the invention can vary in a wide range extending from 5 to 150 μm, preferably from 7 to 80 μm. The total thickness of the multilayer film can also vary in a wide range extending from 20 to 400 μm.

[0310] According to a preferred embodiment, the multilayer film according to the invention has from two to four substrate layers, the film then being referred to as bilayer, trilayer or quadlayer, respectively, preferably three or four substrate layers.

[0311] According to a particular embodiment, the membrane is chosen from:

[0312] - a three-layer film which is (PET / aluminum) / RCPP, the two-component composition according to the invention bonding aluminum and RCPP, and

[0313] - A four-layer film of (PET / aluminum) / nylon / RCPP, the two-component composition according to the invention bonding aluminum and nylon, and nylon and RCPP.

[0314] Finally, the invention relates to the use of the multilayer film according to the invention for the manufacture of flexible packaging. In fact, the multilayer film according to the invention can be used to manufacture the most diverse flexible packaging, which is formed by heat sealing (or hot welding) technology and then closed (after a step of placing the product intended for the consumer in a suitable state). Preferably, the multilayer film according to the invention is used for the manufacture of food packaging.

[0315] According to a preferred embodiment, the multilayer film according to the invention is used for the manufacture of flexible packaging intended for sterilization processes, such as the sterilization of food placed in said flexible packaging.

[0316] All embodiments described above can be combined with one another. In particular, the various above-mentioned components in the two-component composition, and in particular the preferred embodiments, can be combined with one another.

[0317] The following examples illustrate the invention without limiting the invention.

[0318] Example

[0319] Embodiment 1: Materials and methods

[0320] Material

[0321] The following materials were implemented:

[0322] - polyester A, obtained from adipic acid (AA), isophthalic acid (IPA), and diethylene glycol (DEG), wherein the molar ratio of AA:IPA:DEG is 1:1:2.7, which is a polyester polyol having an OH value of 133-148 mg KOH / g, a number average molecular weight of 800 g / mol, a functionality equal to 2 (meaning that polyester A has an average of 2 -OH groups per molecule), and which is non-crystalline;

[0323] - polyester B, obtained from isophthalic acid (IPA), diethylene glycol (DEG), and castor oil, wherein the molar ratio of IPA:DEG:castor oil is 1:1.5:1, which is a polyester polyol having an OH value of 158-172 mg KOH / g, a number average molecular weight of 750 g / mol, a functionality equal to 2.2 (meaning that polyester B has an average of 2.2 -OH groups per molecule), and which is non-crystalline;

[0324] - polyester C1, obtained from adipic acid (AA) and 1,4-butanediol (BDO), wherein the molar ratio of AA:BDO is 1:1.23, which is a polyester polyol having an OH value of 107-117 mg KOH / g, a number-average molecular weight of 1000 g / mol, a functionality equal to 2 (ie 2 -OH groups per molecule), and which is crystalline;

[0325] - polyester C2, obtained from adipic acid (AA) and 1,4-butanediol (BDO), wherein the molar ratio of AA:BDO is 1:1.11, which is a polyester polyol having an OH value of 54-58 mg KOH / g, a number average molecular weight of 2000 g / mol, a functionality equal to 2 (ie 2 -OH groups per molecule), and which is crystalline;

[0326] - polyester C3, obtained from adipic acid (AA) and 1,4-butanediol (BDO), wherein the molar ratio of AA:BDO is 1:1.07, which is a polyester polyol having an OH value of 35-39 mg KOH / g, a number average molecular weight of 3000 g / mol, a functionality equal to 2 (ie 2 -OH groups per molecule), and which is crystalline;

[0327] - polyester C4, obtained from adipic acid (AA) and 1,4-butanediol (BDO), wherein the molar ratio of AA:BDO is 1:1.35, which is a polyester polyol having an OH value of 153-167 mg KOH / g, a number average molecular weight of 700 g / mol, a functionality equal to 2 (ie 2 -OH groups per molecule), and which is crystalline;

[0328] - ETEROL 5103, commercially available from Eternal Materials, a polyester polyol obtained from adipic acid, diethylene glycol, and trimethylolpropane, having a functionality equal to 2.5 (ie an average of 2.5 -OH groups per molecule) and which is non-crystalline;

[0329] -VORANOL marketed by Dow TM 1000LM (PPG 1000 diol), a polyether polyol (polypropylene glycol) having a number average molecular weight of 1000 g / mol and a functionality equal to 2 (i.e., 2 -OH groups per molecule);

[0330] - CHE-204 (PPG 400 diol), a polyether polyol (polypropylene glycol), commercially available from Changhua Chemical, having a number average molecular weight of 400 g / mol and a functionality equal to 2 (ie 2 -OH groups per molecule);

[0331] -VORANOL marketed by Dow TM CP 450 (PPG 450 triol), a polyether polyol (polypropylene glycol) having a number average molecular weight of 450 g / mol and a functionality equal to 3 (ie 3 -OH groups per molecule);

[0332] - trimethylolpropane (TMP), commercially available from Perstorp, a chain extender having a functionality equal to 3 (ie 3 -OH groups per molecule);

[0333] - 1,4-butanediol (BDO), a low molecular weight polyol commercially available from Xinjiang Markor Chemical Industry, having a functionality equal to 2 (ie 2 -OH groups per molecule);

[0334] - isophorone diisocyanate (IPDI), a polyisocyanate commercially available from Wanhua, having an -NCO content of 37.5% by weight, based on the total weight of IPDI;

[0335] - Desmodur® 2460M (MDI), commercially available from Covestro, comprising a mixture of at least 39.2% by weight of 4,4′-methylenediphenyl diisocyanate and about 55% by weight of 2,4′-methylenediphenyl diisocyanate, a polyisocyanate having an —NCO content of 33.5% by weight, based on the total weight of the MDI;

[0336] - Dynasylan® 1124, bis(trimethoxysilylpropyl)amine, a silane coupling agent, commercially available from Evonik;

[0337] - Silquest A-1100 (AMEO), (3-aminopropyl)triethoxysilane, a silane coupling agent, commercially available from MOMENTIVE;

[0338] - Silquest A-187 (GLYMO), (3-glycidyloxypropyl)trimethoxysilane, commercially available from MOMENTIVE, a silane coupling agent;

[0339] -Triethanolamine, analytical reagent grade, chain extender, commercially available from Titan chemical.

[0340] Preparation of polyesters A, B, C1, C2, C3 and C4

[0341] Under a nitrogen atmosphere, the reactor is loaded with the raw materials for obtaining the polyester polyol as indicated above (e.g. adipic acid and 1,4-butanediol for polyester C1, wherein the molar ratio of AA:BDO is 1:1.23) and heated to about 150°C to start discharging the water generated by the reaction. Then, a catalyst (e.g. tetra-n-butyl titanate) is added to the reactor and the temperature is raised to about 230°C. When the water to be discharged reaches 95% of the theoretical amount, vacuum is started and the reaction is carried out at 85-90 kPa. The reaction is stopped when the acid value is less than 2.0 mg KOH / g (measured according to ISO 2114-2000, method A).

[0342] The hydroxyl value of each polyester was measured according to ISO 14900-17 (Method A), and the number average molecular weight of each polyester was measured by size exclusion chromatography (or SEC) with polystyrene calibration.

[0343] Preparation of Component A

[0344] Component A was prepared as described below:

[0345] The reactor was charged with polyols under stirring and under nitrogen atmosphere and the temperature was set between 50°C and 60°C. The reactor was then charged with IPDI and kept at 80°C for 3 hours (or with MDI for comparative composition CE1 and kept at 80°C for 1.5 hours). Dynasylan® 1124 was then optionally added to the reactor and the temperature was kept at 75-80°C for 30 minutes. The temperature was then lowered to below 50°C.

[0346] The NCO content of component A is measured according to standard ASTM D2572 (2010), and the viscosity is measured by a Brookfield LVT viscometer and using standard EN ISO 2555 (2018).

[0347] Preparation of component B

[0348] Component B was prepared as described below:

[0349] The reactor was charged with polyol and triethanolamine under nitrogen atmosphere and the temperature was set at 50-60°C and kept under stirring for 30 minutes. AMEO was then added to the reactor and placed under stirring for 30 minutes.

[0350] Alternatively, when GLYMO was added instead of AMEO: the reactor was charged with polyol and GLYMO and the mixture was stirred at 50°C for 1 h.

[0351] The hydroxyl value of component B is measured according to ISO 14900-17 (method A), and the viscosity is measured by a Brookfield LVT viscometer and using standard EN ISO 2555 (2018).

[0352] Preparation and application of two-component compositions

[0353] Component A was then mixed with component B at a temperature of 55° C. (or 45° C. for composition CE1).

[0354] The pot life is measured at 55° C. (or at 45° C. for composition CE1) and corresponds to the time required for the composition (obtained after mixing components A and B) to reach a viscosity of 3000 cP (measured by Brookfield LVT viscometer and using standard EN ISO 2555 (2018)).

[0355] The two-component composition is used as an adhesive on a substrate comprising the following layers: polyethylene terephthalate (PET), aluminum (AL) and retort cast polypropylene (RCPP), and is applied between AL and RCPP: (PET / AL) / / RCPP; receiving bonded PET and AL layers. The coating weight is about 2 g / m 2 After lamination at 55° C. (or at 45° C. for composition CE1), the final laminated substrates were cured in an oven at a temperature of 50° C. for 3 or 5 days.

[0356] The two-component composition was also used as an adhesive on a substrate comprising the following layers: PET, AL, nylon (NY) and RCPP, and was applied between AL and NY and between NY and RCPP: (PET / AL) / / NY / / RCPP. The coating weight was about 2 g / m 2 After lamination at 55°C, the final laminated substrates were cured in an oven at a temperature of 50°C for 3 or 5 days.

[0357] Then, each of the laminated substrates was formed into a bag (20 cm×10 cm) by heat sealing (about 170-180°C), and each bag was filled with 100 mL of water and sterilized in an autoclave at 121°C for 40 min. Then, after retorting, the bond strength value (BSV) of the adhesive was measured according to GB / T 8808-1988 soft composite plastic material peeling test method. More specifically, after retorting, a strip having a width of 15 mm was cut from the bag, and the bond strength was tested at 90 degrees at 300 mm / min using a tensile machine (90°T peel test). All bond strength values ​​are the average of three test results in the mechanical direction.

[0358] Embodiment 2: Properties of the Compositions According to the Invention and Comparative Compositions

[0359] As described in Example 1 "Preparation of Component A", the components of Table 1 were used to prepare component A for two-component compositions 1 to 6 according to the present invention and two-component comparative compositions CE1 to CE3 (polyester A, polyester C1-C4, PPG 1000 diol, PPG 400 diol and BDO are the polyols mentioned in the preparation process). The percentage for each ingredient is the weight percentage based on the total weight of component A. The NCO content is the weight percentage based on the total weight of component A.

[0360]

[0361] Table 1: Component A

[0362] As described in Example 1 "Preparation of Component B", the components of Table 2 were used to prepare component B for two-component compositions 1 to 6 according to the present invention and two-component comparative compositions CE1 to CE3 (polyester A, polyester B, Eternal 5103, PPG400 triol and TMP are the polyols mentioned in the preparation process). The percentage for each component is the weight percentage based on the total weight of component B.

[0363]

[0364] Table 2: Component B

[0365] Then, two-component compositions were prepared and their properties were evaluated as described in Example 1 "Preparation and use of two-component compositions" and are set forth in Table 3 below.

[0366]

[0367] * Usable life at 45°C

[0368] Table 3: Properties of two-component compositions

[0369] Table 3 shows that after sterilization, all two-component compositions according to the invention have a bond strength value (BSV) greater than or equal to 3.5 N / 15 mm and most have a BSV greater than or equal to 4.5 N / 15 mm (except for composition 4 with AL / NY which is slightly lower). According to the national standard GB / T 10004-2008, BSV≥3.5 N / 15 mm corresponds to semi-high temperature cooking grade and BSV≥4.5 N / 15 mm corresponds to high temperature cooking grade.

[0370] All two-component compositions according to the invention therefore have good adhesive properties even after sterilization, which means that they have good heat resistance.

[0371] However, for all substrates tested, the comparative composition CE2, in which component A is obtained from a non-crystalline polyester polyol (polyester A), exhibits a significantly lower BSV than the compositions 1, 5 and 6 according to the invention, which comprise in component A crystalline polyester polyols C1, C2 and C4, respectively.

[0372] Thus, replacing the non-crystalline polyester polyol in component A by a crystalline polyester polyol results in an improvement in the BSV after sterilization.

[0373] Furthermore, for all substrates tested, the comparative composition CE3, in which component A is obtained from a crystalline polyester polyol having a number average molecular weight of 3000 g / mol (polyester C3), shows a significantly lower BSV than the compositions 1, 5 and 6 according to the invention, which comprise in component A crystalline polyester polyols C1, C2 and C4 respectively having a number average molecular weight below 3000 g / mol.

[0374] Therefore, the number average molecular weight of the crystalline polyester polyol in component A has an influence on the BSV after sterilization.

[0375] Finally, compositions 2 and 5 according to the invention give similar or even better BSV after sterilization compared to the comparative composition CE1 obtained from MDI (aromatic polyisocyanate) and GLYMO (epoxysilane), with the further advantage that the compositions according to the invention are free of primary aromatic amines and epoxysilanes.

Claims

1. A two-component composition comprising: - Component A, comprising a reaction product obtained by reacting at least: - aliphatic polyisocyanates, and - a crystalline polyester polyol having a number average molecular weight of less than 3000 g / mol; and - Component B comprising: - at least one polyester polyol, - a chain extender, and -Silane coupling agent.

2. The two-component composition according to claim 1, wherein the aliphatic polyisocyanate is selected from the group consisting of isophorone diisocyanate (IPDI), dicyclohexylmethane 4,4'-diisocyanate (H12MDI), 1,4-cyclohexylene diisocyanate, 1,2-cyclohexylene diisocyanate, 2,4-diisocyanate-1-methylcyclohexane, 1,3-diisocyanate-2-methylcyclohexane, m-xylylene diisocyanate (m-XDI), hydrogenated m-xylylene diisocyanate (m-H6XDI), tetramethylxylene diisocyanate (TMXDI), 1,2-ethylene diisocyanate, 1,3-propylene diisocyanate, 1,4-butylene diisocyanate, 1,5-pentamethylene diisocyanate (PDI), 1,6-hexamethylene diisocyanate (HDI), and mixtures thereof.

3. The two-component composition according to claim 1 or 2, wherein the crystalline polyester polyol in component A is obtained by reacting: - a polycarboxylic acid selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, fumaric acid or its dimer, maleic acid or its dimer, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, phthalic acid, terephthalic acid, their ester-forming derivatives, and mixtures thereof, and - a polyol selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, bisphenol A, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and mixtures thereof.

4. The two-component composition according to any one of claims 1 to 3, wherein the reaction product in component A is obtained by reacting an aliphatic polyisocyanate and a crystalline polyester polyol and at least also a polyether polyol.

5. The two-component composition according to claim 4, wherein the polyether polyol is selected from polyethylene glycol, polypropylene glycol, poly(tetramethylene ether) glycol (PTMEG), and copolymers thereof such as block copolymers of polyethylene glycol and polypropylene glycol.

6. The two-component composition according to any one of claims 1 to 5, wherein the reaction product in component A is obtained by reacting an aliphatic polyisocyanate and a crystalline polyester polyol at least additionally with a low molecular weight polyol.

7. The two-component composition according to any one of claims 1 to 6, wherein the reaction product in component A is obtained by reacting an aliphatic polyisocyanate and a crystalline polyester polyol at least further with a silane coupling agent.

8. The two-component composition according to any one of claims 1 to 7, wherein the polyester polyol in component B is obtained by reacting: - a polycarboxylic acid selected from the group consisting of succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, fumaric acid or its dimer, maleic acid or its dimer, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, phthalic acid, terephthalic acid, their ester-forming derivatives, and mixtures thereof, and - a polyol selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propylene glycol, trimethylolpropane, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, bisphenol A, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and mixtures thereof, - optionally with at least one fatty acid comprising a fatty acid containing one or more hydroxyl groups and / or one or more triglycerides thereof. 9 . The two-component composition according to claim 1 , wherein component B comprises at least two polyester polyols, preferably exactly two polyester polyols.

10. The two-component composition according to any one of claims 1 to 9, wherein the chain extender in component B is selected from 1,4-butanediol, ethylene glycol, diethylene glycol, 1,6-hexanediol, 1,2,3-propanetriol, trimethylolethane, trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, diethanolamine, ethanolamine, and mixtures thereof.

11. The two-component composition according to any one of claims 1 to 10, wherein the silane coupling agent in component B is an aminosilane compound.

12. The two-component composition according to any one of claims 1 to 11, which is free of primary aromatic amines.

13. Use of the two-component composition according to any one of claims 1 to 12 as an adhesive for producing articles, in particular multilayer films, the adhesive having an adhesive strength value after sterilization of greater than or equal to 3.5 N / 15 mm.

14. Multilayer film comprising at least two substrate layers bonded together by a continuous layer, wherein the continuous layer consists of the two-component composition according to any one of claims 1 to 12.

15. Use of the multilayer film according to claim 14 for the manufacture of flexible packaging intended for sterilization processes, such as the sterilization of food placed in the flexible packaging.

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