Process for the preparation of polyurethane polymers

Abstract

The present invention relates to a process for preparing a polyurethane polymer comprising: (A) contacting at least one isophorone diisocyanate (IPDI) monomer with at least one first polyol in the presence of at least one first catalyst; (B) contacting a urethane prepolymer with at least one second polyol in the presence of at least one second catalyst to form a polyurethane polymer, wherein the first catalyst is a guanidine-type catalyst and the second catalyst is an organometallic catalyst, or wherein the first catalyst is an organometallic catalyst and the second catalyst is a guanidine-type catalyst. The present invention also relates to a two-component composition and its use as an adhesive for bonding two substrates together. Finally, the present invention relates to an article comprising at least one layer obtained by crosslinking said composition and to a process for preparing said article.

Description

Invention Field

[0001] This invention relates to a method for preparing polyurethane polymers by sequentially using a guanidine-type catalyst and an (organo)metal catalyst. The invention also relates to a two-component composition and its use. Furthermore, the invention relates to articles prepared using this composition and methods for preparing said articles. Technical Background

[0002] Flexible packaging used for packaging various products, such as those manufactured for the food, cosmetics, or detergent industries, typically consists of multiple thin layers (in sheet or film form) with a thickness generally between 5 and 150 μm, and is made of different materials, such as paper, metals (e.g., aluminum), or thermoplastic polymers. Corresponding (multilayer) composite films, typically 20 to 400 μm thick, allow for the combination of the properties of different single-layer materials, thus providing consumers with a set of characteristics suitable for flexible final packaging, such as: its visual appearance (especially printed elements presenting information related to the packaged product and intended for consumer use), its function as a barrier against atmospheric moisture or oxygen, no risk of toxicity or alteration of the sensory properties of the packaged food upon contact with food, chemical resistance for certain products (such as ketchup or liquid soap), and excellent high-temperature resistance, for example, under pasteurization or sterilization conditions.

[0003] To form the final packaging, multi-layer films are typically formed by heat sealing at temperatures of approximately 120 to 250°C, a technique also used to seal packaging around products intended for consumers.

[0004] In industrial lamination (also referred to by the term "lamination"), the individual material layers that make up a multilayer film are combined or assembled by lamination.

[0005] These methods use adhesives (or glues) and specially designed equipment (or machines). The resulting multilayer films are typically defined by the term "laminated".

[0006] These methods first include the step of applying an adhesive to a first material layer, which involves depositing a continuous adhesive layer of controlled thickness, typically greater than or equal to 1 μm and less than 25 μm, corresponding to a similarly controlled thickness and typically not exceeding 25 g / m³. 2 The amount (or weight) of adhesive. This coating step is followed by a step of laminating a second material layer that is the same as or different from the first layer, which includes applying the second material layer onto the first material layer covered with the adhesive layer under pressure.

[0007] Polyurethane-based adhesives are commonly used in such applications.

[0008] However, polyurethane-based compositions often have the disadvantage of containing high residual levels of diisocyanates derived from the polyurethane synthesis reaction, which can lead to numerous drawbacks, particularly toxicity issues, especially in the case of aromatic diisocyanates. In fact, polyurethanes do not have labeling requirements that the residual diisocyanate content must be as low as possible, preferably below 0.1% by weight. To achieve such low residual content, the preparation methods may be limited.

[0009] Furthermore, polyurethane-based compositions are typically prepared using organometallic catalysts, particularly tin-based catalysts. However, some of these catalysts pose significant toxicological risks to humans and the environment. Therefore, it is necessary to avoid or reduce the use of toxic catalysts.

[0010] The article "Relative reactivity of isocyanate groups of isophorone diisocyanate. Unexpected high reactivity of the secondary isocyanate group" by H.-K. Ono et al. (Journal of Polymer Science, 1985, vol. 23, 509-515) deals with isophorone diisocyanate and describes the reactivity differences between the two isocyanate groups. The article also describes the reaction of this diisocyanate with n-butanol in the presence of the catalyst DABCO and its dependence on the regioselectivity of the catalyst.

[0011] R. The article "Selectivity of isophorone diisocyanate in theurethane reaction influence of temperature, catalysis, and reaction partners" (Journal of Coatings Technology, 1997, vol. 69, 51-57) by [Authors' Name] deals with the synthesis of urethane prepolymers and describes the effects of catalyst type, temperature, and -OH group type on the selectivity of isophorone diisocyanate.

[0012] The article “Kinetics of urethane formation from isophoronediisocyanate: the catalyst and solvent effects” by SVKarpov et al. (Kinetics and Catalysis, 2016, vol. 57, 422-428) describes the effects of catalyst and solvent on kinetic parameters during the reaction of isophorone diisocyanate with various alcohols to form polyurethane.

[0013] The articles "Cyclic guanidines as efficient organocatalysts for the synthesis of polyurethanes" by J. Alsarraf et al. (Macromolecules, 2012, vol. 45, 2249-2256) and "Latent catalysts based on guanidine templates for polyurethane synthesis" (Polymer Chemistry, 2013, vol. 4, 904-907) describe the use of guanidine-type catalysts for the synthesis of polyurethanes from polyisocyanates such as isophorone diisocyanate, toluene diisocyanate, and 4,4'-methylenebis(cyclohexyl isocyanate) and various polyols.

[0014] Reference FR2964106A1 describes the use of guanidine catalysts to synthesize polyurethane.

[0015] Document WO2017 / 171996 relates to an adhesive composition comprising a polyurethane composition and a catalyst, said catalyst being a reaction product of an amidine, guanidine, or amine compound with carbon dioxide and water, an alcohol, or a thiol.

[0016] Therefore, there is a need for a method that allows the acquisition of polyurethane polymers, particularly isophorone diisocyanate-based polyurethane polymers, while improving the crosslinking kinetics for polymer formation and avoiding the use of toxic reagents. There is also a need for a polyurethane-based composition that allows for improved crosslinking kinetics for polymer formation and is obtained while avoiding the use of toxic reagents. Summary of the Invention

[0017] This invention first relates to a method for preparing a polyurethane polymer, comprising:

[0018] -(A) In the presence of at least one first catalyst, at least one isophorone diisocyanate (IPDI) monomer is contacted with at least one first polyol to form a urethane prepolymer;

[0019] -(B) In the presence of at least one second catalyst, a urethane prepolymer is contacted with at least one second polyol to form a polyurethane polymer;

[0020] in:

[0021] - The first catalyst is selected from catalysts of general formula (I) or catalysts of general formula (II):

[0022]

[0023] in:

[0024] -R 0 It is a group containing 1 to 10 carbon atoms, selected from straight-chain or branched alkyl, cycloalkyl, or aralkyl groups.

[0025] -R 1 R 2 and R 3 Independently representing a group containing 1 to 10 carbon atoms, selected from straight-chain or branched alkyl, cycloalkyl, or aralkyl groups.

[0026] -R 4 A group representing a hydrogen atom or containing 1 to 10 carbon atoms, selected from straight-chain or branched alkyl, cycloalkyl, aralkyl, or aryl groups.

[0027] -R 1 R 2 R 3 and R 4 At least two of them are optionally joined in the ring, and

[0028] -M + Represents a monovalent cation; and

[0029] –The second catalyst is an (organo)metal catalyst;

[0030] Or among them:

[0031] – The first catalyst is an (organo-metal) catalyst; and

[0032] - The second catalyst is selected from catalysts of general formula (I) or catalysts of general formula (II).

[0033] According to some implementation schemes, the first catalyst is selected from catalysts of general formula (I) or general formula (II), and the second catalyst is an (organo)metal catalyst.

[0034] According to some embodiments, the first polyol and / or the second polyol are selected from polyether polyols, polyester polyols and mixtures thereof, and preferably the first polyol and / or the second polyol comprises polypropylene glycol.

[0035] According to some implementation schemes, the second polyol is the same as the first polyol.

[0036] According to some implementation schemes, M + It represents the Na+ cation.

[0037] According to some implementation plans, R 0 Selected from methyl or benzyl.

[0038] According to some implementation plans, R 1 and R 2 Or R 1 and R 4 It is included in the ring.

[0039] According to some implementation plans, R 1 and R 2 Included in the first ring and R 3 and R 4 It is included in the second ring.

[0040] According to some embodiments, the (organo)metal catalyst is selected from tin catalysts, zinc catalysts, bismuth catalysts, titanium catalysts, iron catalysts, copper catalysts, zirconium catalysts, aluminum catalysts and combinations thereof, and preferably the (organo)metal catalyst is selected from zinc catalysts, bismuth catalysts, titanium catalysts, iron catalysts, copper catalysts, aluminum catalysts and zirconium catalysts.

[0041] According to some embodiments, in the step of contacting at least one isophorone diisocyanate (IPDI) monomer with at least one first polyol, the NCO / OH molar ratio is 1.5 to 5, preferably 1.5 to 4, more preferably 1.5 to 3, and more preferably 1.5 to 2.

[0042] The present invention also relates to a two-component composition for preparing a polyurethane polymer according to the above method, the composition comprising:

[0043] -NCO component, which contains the urethane prepolymer prepared by step (A) of this method;

[0044] - and OH components, which contain at least one second polyol and a second catalyst.

[0045] According to some implementation schemes, the NCO component also includes one or more additives selected from plasticizers, solvents, pigments, adhesion promoters, hygroscopic agents, UV stabilizers (or antioxidants), fluorescent materials, rheology additives, and mixtures thereof.

[0046] According to some implementation schemes, the NCO / OH molar ratio of the NCO component to the OH component is 1.5 to 2.5, preferably 1.7 to 2.0.

[0047] The present invention also relates to the use of the composition as an adhesive for bonding two substrates together.

[0048] The present invention also relates to an article comprising at least one layer obtained by crosslinking the composition.

[0049] The present invention also relates to a method for preparing the article, comprising:

[0050] - Mix the NCO component and OH component of the composition;

[0051] – Apply the mixture to the surface of the substrate; and

[0052] – This allows the surface to come into contact with the surface of another substrate.

[0053] This invention enables the fulfillment of the aforementioned requirements. More specifically, this invention provides a method for obtaining polyurethane polymers, particularly isophorone diisocyanate-based polyurethane polymers, while improving the crosslinking kinetics for polymer formation and avoiding the use of toxic reagents. This invention also provides a polyurethane-based composition that allows for improved crosslinking kinetics for polymer formation and is obtained while avoiding the use of toxic reagents.

[0054] This is achieved by means of the method of the present invention. More specifically, this method comprises two separate steps: a first step of forming a urethane prepolymer using a first catalyst and a second step of forming a polyurethane polymer using a second catalyst. One of the first catalyst or the second catalyst is a guanidine-type catalyst, and the other of the first catalyst or the second catalyst is an organometallic catalyst. Using one or the other as the first catalyst (guanidine-type catalyst or organometallic catalyst) allows for improved crosslinking kinetics. Moreover, it allows for control of the regioselectivity of the reaction. In fact, isophorone diisocyanate is an asymmetric diisocyanate containing a first isocyanate group attached to a primary carbon atom (C1) and a second isocyanate group attached to a secondary carbon atom (C2). Using a guanidine-type or organometallic first catalyst allows for improved regioselectivity of the reaction, that is, in the first step, the diol preferentially reacts with either the first isocyanate group or the second isocyanate group, and this selectivity depends on the first catalyst. More specifically, using a guanidine-type catalyst as the first catalyst favors the reaction of isocyanate groups attached to the primary carbon atom (C1), while using an (organo)metal catalyst favors the reaction of isocyanate groups attached to the secondary carbon atom (C2). Then, using a second catalyst with reverse regioselectivity (guanidine-type or (organo)metal-type, but different from the first catalyst) allows the glycol to react with another of the first or second isocyanate groups of the urethane prepolymer to form a polyurethane polymer.

[0055] Advantageously, using a guanidine catalyst as the first catalyst also allows for control over the amount of residual monomer.

[0056] Detailed description

[0057] The present invention will now be described in more detail, but not in a limiting manner, in the following description.

[0058] This invention relates to a method for preparing a polyurethane polymer.

[0059] This method includes a first step of forming a urethane prepolymer and a second step of formulating a polyurethane adhesive. "Urethane prepolymer" should be understood as an intermediate in polyurethane synthesis, corresponding to a polymer containing at least two urethane groups and at least two reactive isocyanate functional groups in its main chain that enable it to undergo at least one addition polymerization reaction.

[0060] In the following text, the first catalyst is a guanidine catalyst of general formula (I) or (II) and the second catalyst is an (organo)metal catalyst.

[0061] However, all descriptions apply equally to cases where the first catalyst is an (organo)metal catalyst and the second catalyst is a guanidine catalyst of general formula (I) or (II).

[0062] The term "(organic) metal" encompasses both metal catalysts and organometallic catalysts.

[0063] Step 1 – Formation of urethane prepolymer

[0064] The first step of the method according to the invention is carried out by contacting at least one isophorone diisocyanate (IPDI) monomer with at least one first polyol in the presence of a first guanidine catalyst, wherein the guanidine catalyst contains a structure consisting of three nitrogen atoms bonded to a carbon atom, one of which is bonded to the carbon atom by a double bond. The guanidine catalyst has general formula (I) or general formula (II).

[0065]

[0066] R 0 R 1 R 2 and R 3 Unlike hydrogen atoms, in other words, at least two nitrogen atoms in the catalyst are not protonated. This allows for high regioselectivity (explained below) and thus reduces the residual monomer content.

[0067] In equation (I), R 0 It is a group containing 1 to 10 carbon atoms, and preferably a group containing 1 to 7 carbon atoms.

[0068] R 0 It can be a straight-chain or branched alkyl group, a cycloalkyl group, or an aralkyl group. For example, it can be methyl, ethyl, n-propyl, isopropyl, cyclopropyl, tert-butyl, isobutyl, n-butyl, sec-butyl, cyclobutyl, cyclopentyl, cyclohexyl, n-hexyl, n-octyl, 2-ethylhexyl, n-decyl, or an alkyl group substituted with an aryl group. Other alkyl groups (aralkyl groups) include benzyl, alkyl groups substituted with ester groups, alkyl groups substituted with tertiary amino groups, and alkyl groups substituted with alkyldialkoxysilanes or alkyltrialkoxysilanes.

[0069] According to some implementation plans, R 0 It is methyl, ethyl, n-propyl, n-butyl, isobutyl, n-pentyl, or n-hexyl.

[0070] According to other implementation schemes, R 0 It is benzyl.

[0071] In equation (II), M + This indicates a monovalent cation, preferably selected from Li. + Na + and K+ .

[0072] More preferably, M + Yes + cation.

[0073] R 1 R 2 and R 3 Independently represents a group containing 1 to 10 carbon atoms.

[0074] Therefore, R 1 R 2 and R 3 It can be independently selected from straight-chain or branched alkyl, cycloalkyl, or aralkyl groups. For example, R 1 R 2 and R 3 It can be independently selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, tert-butyl, isobutyl, n-butyl, sec-butyl, cyclobutyl, cyclopentyl, cyclohexyl or aryl-substituted alkyl (arylalkyl), such as alkylphenyl.

[0075] R 4 It can be a hydrogen atom or a group containing 1 to 10 carbon atoms. It can be a straight-chain or branched alkyl group, cycloalkyl, arylalkyl, or aryl. For example, R 4 It may be selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, tert-butyl, isobutyl, n-butyl, sec-butyl, cyclobutyl, cyclopentyl, cyclohexyl, aryl-substituted alkyl (arylalkyl) such as alkylphenyl, or unsubstituted or substituted phenyl groups such as alkyl (= alkylaryl) or cycloalkyl, alkoxy, halogen, nitro and carbonyl.

[0076] According to some preferred implementation schemes, R 1 R 2 R 3 and R 4 It can be an alkyl group containing 1 to 7 carbon atoms. For example, R 1 R 2 and R 3 It can be methyl, and R 4 It can be methyl, isopropyl, cyclohexyl, or tert-butyl.

[0077] According to some preferred implementation schemes, R 1 R 2 and R 3 It can be an alkyl group containing 1 to 7 carbon atoms, such as methyl, and R 4 It can be aryl, such as phenyl.

[0078] Alternatively, and preferably, R 1 R2 R 3 and R 4 At least two of the atoms in the group are bonded to the ring. This means that there is a covalent bond between an atom of one group and an atom of another group.

[0079] Therefore, according to some implementation schemes, R 1 and R 2 Or R 3 and R 4 It can be incorporated into a ring. This makes it possible to obtain monocyclic catalysts, such as those of general formula (III) or (IV):

[0080]

[0081] In the case of a catalyst of formula (III), the group R 1 and R 4 Ring formation occurs, and in the case of a catalyst of formula (IV), the R group... 1 and R 2 A ring is formed.

[0082] In these cases of catalysts of formula (III), n can be 0 to 3, preferably 0 to 1, and more preferably n can be 1. Therefore, it can be a penta-atom ring, a hexa-atom ring, a hepta-atom ring, or an octa-atom ring, preferably a penta-atom or hexa-atom ring, and more preferably a hexa-atom ring.

[0083] In the case of a catalyst of formula (IV), u can be 1 to 4, preferably 1 to 2, and more preferably 1. Therefore, it can be a penta-atom ring, a hexa-atom ring, a hepta-atom ring, or an octa-atom ring.

[0084] In the catalysts of formulas (III) and (IV), R 0 R 2 R 3 and R 4 It has the same meaning as equations (I) and (II).

[0085] R 5 R 6 R 7 R 8 R 9 R 10 R 11 R 12 R 13 and R 14 It can be independently selected from hydrogen atoms or groups containing 1 to 10 carbon atoms, preferably 1 to 7 carbon atoms.

[0086] Therefore, R 5 R 6 R7 R 8 R 9 R 10 R 11 R 12 R 13 and R 14 It can be independently selected from hydrogen atoms, straight-chain or branched alkyl groups, cycloalkyl groups, aralkyl groups, or aryl groups. For example, R 5 R 6 R 7 R 8 R 9 R 10 R 11 R 12 R 13 and R 14 It can be independently selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, tert-butyl, isobutyl, n-butyl, sec-butyl, cyclobutyl, cyclopentyl, cyclohexyl, alkyl substituted with aryl (arylalkyl), such as alkylphenyl, unsubstituted or substituted with one or more groups such as alkyl (= alkylaryl) or cycloalkyl, alkoxy, halogen, nitro or carbonyl.

[0087] According to some implementation plans, R 5 R 6 R 7 R 8 R 9 R 10 R 11 R 12 R 13 and R 14 At least one of them, preferably R 5 R 6 R 7 R 8 R 9 R 10 R 11 R 12 R 13 and R 14 At least two of them, preferably R 5 R 6 R 7 R 8 R 9 R 10 R 11 R 12 R 13 and R 14 At least three of them, more preferably R 5 R 6 R 7 R 8 R9 R 10 R 11 R 12 R 13 and R 14 At least four of them, preferably R 5 R 6 R 7 R 8 R 9 R 10 R 11 R 12 R 13 and R 14 At least five of them, or even better R 5 R 6 R 7 R 8 R 9 R 10 R 11 R 12 R 13 and R 14 It consists entirely of hydrogen atoms.

[0088] Although not shown in equations (III) and (IV) above, -NR 0 The group can also be -NM + Group substitution, where M + As stated above.

[0089] According to other preferred embodiments, R 1 and R 2 It is joined in the first ring and R 3 and R 4 It is incorporated into the second ring. Such catalysts are bicyclic. Bicyclic catalysts can, in particular, have the general formula (V):

[0090]

[0091] In the case of a catalyst of formula (V), the group R 1 and R 2 The first ring is formed and the group R 3 and R 4 A second ring is formed.

[0092] In this case, t can be a number from 1 to 4, preferably from 1 to 3, and more preferably t can be 1 or 2. Therefore, it can be a penta-atom ring, a hexa-atom ring, a hepta-atom ring, or an octa-atom ring.

[0093] Additionally, u is as defined above.

[0094] According to some implementation schemes, t and u are different.

[0095] According to the preferred embodiment, t and u are the same, for example, n and u are equal to 1 or n and u are equal to 2.

[0096] R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 They can be independently selected from hydrogen atoms or groups containing 1 to 10 carbon atoms, preferably 1 to 7 carbon atoms.

[0097] Therefore, R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 It can be independently selected from hydrogen atoms, straight-chain or branched alkyl groups, cycloalkyl groups, arylalkyl groups, or aryl groups. For example, R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 It can be independently selected from methyl, ethyl, n-propyl, isopropyl, cyclopropyl, tert-butyl, isobutyl, n-butyl, sec-butyl, cyclobutyl, cyclopentyl, cyclohexyl, alkyl substituted with aryl (arylalkyl), such as alkylphenyl, unsubstituted or substituted with one or more groups such as alkyl (= alkylaryl) or cycloalkyl, alkoxy, halogen, nitro or carbonyl.

[0098] According to some implementation plans, R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 At least one of them, preferably R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 At least two of them, preferably R 11 R 12 R 13 R 14R 15 R 16 R 17 and R 18 At least three of them, more preferably R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 At least four of them, preferably R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 At least five of them, preferably R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 At least six of them, preferably R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 At least seven of them, or even more preferably all of R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 It is a hydrogen atom.

[0099] According to some implementation schemes, in the first catalyst of formula (V), R 11 R 12 R 13 R 14 R 15 R 16 R 17 and R 18 It is a hydrogen atom and t and u equal 1, or t and u equal 2, or t equal 1 and u equal 2, or t equal 2 and u equal 1, or t equal 2 and u equal 3, or t equal 2 and u equal 4, or t equal 3 and u equal 2, or t equal 4 and u equal 2.

[0100] Although not shown in the above equation (V), -NR 0 Groups can also be -N - M + Replacement, where M + As stated above.

[0101] According to some preferred embodiments, the first catalyst may be selected from 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), benzylated 1,5,7-triazabicyclo[4.4.0]dec-5-ene (Bn-TBD), sodium 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). - Na + ), N-methyl-1,4,6-triazabicyclo[3.3.0]oct-4-ene (MTBO), sodium 1,4,6-triazabicyclo[3.3.0]oct-4-ene (TBO) - Na + ), pentamethylguanidine (PTMG), tetramethylguanidine (TMG), 2-tert-butyl-1,1,3,3-tetramethylguanidine (BTMG), N,N,N',N'-tetramethyl-N”-phenylguanidine (Ph-TMG), 1,3-dimethyl-2-imidazolidineimine, 1,3-dimethyl-2-methyliminoimidazolidine and combinations thereof.

[0102] According to some preferred embodiments, only the first catalyst is in contact with isophorone diisocyanate and polyol.

[0103] According to other embodiments, a mixture of multiple first catalysts (e.g., two, three, or four first catalysts) as described above is contacted with isophorone diisocyanate and one or more polyols.

[0104] Preferably, no other catalyst comes into contact with the reactants in this step, and in particular, the second catalyst, which is described in more detail below, does not come into contact with the reactants in this step.

[0105] The first catalyst (or different first catalysts, if more than one first catalyst is present during this step) may be present in an amount of 50 to 10,000 ppm, preferably 100 to 5,000 ppm, preferably 200 to 1,000 ppm, and more preferably 300 to 800 ppm relative to the weight of the mixture of isocyanate (isophorone diisocyanate) and polyol.

[0106] The one or more polyols may be selected from polyether polyols and polyester polyols and mixtures thereof.

[0107] According to some implementation schemes, a polyol is contacted with isophorone diisocyanate.

[0108] According to other embodiments, multiple polyols (e.g., two, three, or four polyols) are contacted with isophorone diisocyanate.

[0109] The polyols that can be used may have a number average molecular weight of 200 g / mol to 10000 g / mol, preferably 400 to 5000 g / mol, and more preferably 400 to 3000 g / mol.

[0110] The number-average molecular weight of a polyol can be calculated from the hydroxyl value (IOH) expressed in mg KOH / g and the functionality of the polyol, or determined by methods well known to those skilled in the art, such as by using size exclusion chromatography (SEC) of polystyrene standards.

[0111] The polyol may have a hydroxyl functionality of 2 to 6, preferably 2 to 3. In the context of this invention and unless otherwise stated, the hydroxyl functionality of a polyol is the average number of hydroxyl functional groups per mole of the polyol.

[0112] When the polyol is one or more polyester polyols, it may have a number-average molecular weight of 800 g / mol to 15000 g / mol, preferably 800 to 10000 g / mol, preferably 800 to 5000 g / mol, and preferably 800 to 3000 g / mol.

[0113] In polyester polyols, for example, the following can be mentioned:

[0114] - Naturally derived polyester polyols, such as castor oil;

[0115] - Polyester polyols produced by the condensation of one or more aliphatic (linear, branched, or cyclic) or aromatic polyols, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, glycerol, trimethylolpropane, 1,6-hexanediol, 1,2,6-hexanetriol, butanediol, sucrose, glucose, sorbitol, pentaerythritol, mannitol, triethanolamine, N-methyldiethanolamine, and mixtures thereof, with one or more polycarboxylic acids or esters or anhydride derivatives, such as 1,6-hexanediol, dodecanoic acid, azelaic acid, sebacic acid, adipic acid, 1,18-octadecanoic acid, phthalic acid, succinic acid, and mixtures thereof, unsaturated anhydrides, such as maleic anhydride or phthalic anhydride, or lactones, such as caprolactone.

[0116] The aforementioned polyester polyols can be prepared by conventional methods and most of them are commercially available.

[0117] In polyester polyols, for example, products with a hydroxyl functionality of 2 can be mentioned:

[0118] - 3008 (sold by Bostik) is an aliphatic polyester diol with a number-average molecular weight of 425-455 g / mol and a hydroxyl value of 10H of 370-396 mg KOH / g.

[0119] RealkydXTR 10410 (sold by Arkema) is a polyester polyol with a number-average molecular weight of 967-1038 g / mol and a hydroxyl value of 10⁸-116 mg KOH / g.

[0120] Realkyd XTR 09431 (sold by Arkema) is a polyester polyol with a number-average molecular weight of 794-843 g / mol and a hydroxyl value of 133-143 mg KOH / g (IOH).

[0121] Realkyd XTR 10W30 (sold by Arkema) is a polyester polyol with a number-average molecular weight of 967-1038 g / mol and a hydroxyl value of 108-116 mg KOH / g.

[0122] According to some implementation schemes, the polyester polyol is selected from: une estolide polyolde ricin; castor oil; polyester polyols obtained by condensation of different isomers of ethylene glycol, propylene glycol, 1,3-propanediol and / or 1,6-hexanediol with adipic acid and / or phthalic acid; and mixtures thereof.

[0123] When the polyol is one or more polyether polyols, it may have a number-average molecular weight of 200 to 10,000 g / mol, preferably 400 to 10,000 g / mol, preferably 400 to 5,000 g / mol, preferably 400 to 3,000 g / mol.

[0124] Preferably, the polyether polyol has a hydroxyl functionality of 2 to 3.

[0125] In the context of this invention, the polyether polyol is preferably selected from polyoxyethylene polyols, wherein the linear or branched alkylene portion contains 1 to 4 carbon atoms, preferably 2 to 3 carbon atoms.

[0126] More preferably, the polyether polyol may be selected from polyoxyethylene glycol or polyoxyethylene triol, and more preferably from polyoxyethylene glycol, wherein the linear or branched alkylene portion contains 1 to 4 carbon atoms, preferably 2 to 3 carbon atoms.

[0127] As examples of polyoxyethylene glycols or triols that can be used according to the present invention, for example, the following can be mentioned:

[0128] - Polyoxypropylene glycol or triol (also known as polypropylene glycol (PPG) glycol or triol) with a number average molecular weight of 200 g / mol to 10000 g / mol, and preferably 400 g / mol to 12000 g / mol.

[0129] - Polyoxyethylene glycol or triol (also known as polyethylene glycol (PEG) glycol or triol) with a number average molecular weight of 200 g / mol to 10000 g / mol, and preferably 400 g / mol to 10000 g / mol.

[0130] - Polyoxybutylene glycol (also known as polybutylene glycol (PBG) diol or triol) with a number average molecular weight of 200 g / mol to 10000 g / mol.

[0131] - PPG / PEG / PBG diol or triol copolymers or terpolymers with a number average molecular weight of 200 g / mol to 10000 g / mol

[0132] - Polytetrahydrofuran (polyTHF) diols or triols with a number-average molecular weight of 200 g / mol to 10000 g / mol.

[0133] - Polybutanediol (PTMG) with a number-average molecular weight of 200 g / mol to 10000 g / mol,

[0134] - and their mixtures.

[0135] Preferably, the polyether polyol is selected from polyoxypropylene glycol or triol and polyoxyethylene glycol or triol. More preferably, the polyether polyol is selected from polyethylene glycol and polypropylene glycol, and more preferably from polypropylene glycol. The above-mentioned polyether polyols can be prepared by conventional methods and are widely available commercially. They can be obtained, for example, by polymerizing the corresponding epoxides in the presence of a catalyst based on a bimetallic cyanide complex (DMC).

[0136] More preferably, the first polyol may be a mixture of diol and triol, such as polyoxypropylene glycol and polyoxypropylene triol.

[0137] As an example of polyether diols, one could mention those produced by Covestro. Polyoxypropylene glycol sold under the name, for example, has a number average molecular weight of approximately 8057 g / mol. 8200, and has a number-average molecular weight of approximately 4020 g / mol. 4200, or by Dow Corporation in Voranol TMPolyoxypropylene glycols sold under these names include, for example, Voranol 1010L with a number-average molecular weight close to 1000 g / mol, and Voranol 2000L with a number-average molecular weight close to 2004 g / mol.

[0138] As an example of polyether triol, one could mention Dow Corporation under the name... CP3355 sells polyoxypropylene triol with a number-average molecular weight of approximately 3554 g / mol, and polyoxypropylene triol with an average molecular weight of 425-455 g / mol. CP450.

[0139] According to a preferred embodiment, in this step, the NCO / OH molar ratio is 1.5 to 5.5, preferably 1.5 to 4, more preferably 1.5 to 3, and even more preferably 1.5 to 2. For example, the molar ratio can be 1.5 to 2; or 2 to 2.5; or 2.5 to 3; or 3 to 3.5; or 3.5 to 4; or 4 to 4.5; or from 4.5 to 5; or 5 to 5.5. In the context of this invention and unless otherwise stated, the NCO / OH molar ratio corresponds to the molar ratio of the number of isocyanate groups (NCO) carried by the polyisocyanate and polyol used, respectively, to the number of hydroxyl groups (OH). In fact, a low NCO / OH molar ratio allows for a reduction in the amount of residual monomer.

[0140] During the step of contacting at least one isophorone diisocyanate monomer with at least one polyol in the presence of a first catalyst, the hydroxyl groups present on the first polyol can react with the isocyanate end groups of the isophorone diisocyanate (in the presence of the first catalyst) to form a urethane prepolymer. More specifically, as described above, the isophorone diisocyanate is an asymmetric diisocyanate containing a first isocyanate group attached to a primary carbon atom and a second isocyanate group attached to a secondary carbon atom. The presence of the first catalyst allows for improved regioselectivity of the reaction. In other words, the first catalyst allows for "guided" reaction of the hydroxyl groups with either the first or second isocyanate group. In addition to selecting the NCO / OH ratio as previously described, this also allows for control of the amount of residual monomer.

[0141] The regioselectivity of the reaction is calculated according to the method detailed below. Therefore, when x amounts of isophorone diisocyanate are reacted with y amounts of diol, three different products can be obtained, as shown in the following reaction scheme. The amounts y, z, and t, as well as the amount of residual monomer x', depend on the regioselectivity of the reaction. In other words, the diol can react with an isocyanate group attached to a primary carbon atom or with an isocyanate group attached to a secondary carbon atom. In the reaction scheme below, the carbon atoms of the urethane functional group -NH-(C=O)-O- are numbered C1' for primary carbon atoms and C2' for secondary carbon atoms, and the terminal carbon atoms of the urethane functional group -NH-(C=O)-O- are numbered C1 for primary carbon atoms and C2 for secondary carbon atoms.

[0142]

[0143] To determine the relative reactivity of the isocyanate group in isophorone diisocyanate, by... 13 C-NMR spectroscopy (300 MHz 1H, conditions: pulse angle: 30°, relaxation time: 2 s, number of scans > 1000) was used to determine the following molar equivalent ratios:

[0144]

[0145] Since we know that C1' = C2' in the chain, the molar equivalent ratio can be simplified to the molecule:

[0146]

[0147] The r-value (regioselectivity) can only vary between -2 / (C1+C1')+(C2+C2') and +2 / (C1+C1')+(C2+C2'), with a value of 2 in the molecule corresponding to two urethane functional groups at the end of each mole of the prepolymer chain.

[0148] By using this method and a first catalyst, a prepolymer with a regioselectivity (r) greater than or equal to 0.10, preferably greater than or equal to 0.25, more preferably greater than or equal to 0.3 can be obtained. For example, it can have a value of 0.10 to 0.15; or 0.15 to 0.20; or 0.20 to 0.25; or 0.25 to 0.30; or 0.30 to 0.35; or 0.35 to 0.40; or 0.40 to 0.45; or 0.45 to 0.50; or 0.50 to 0.55; or 0.55 to 0.60; or greater than 0.60.

[0149] Specifically, for the NCO / OH ratio of 4.5 to 5.5 in the first step, for example, close to 5, the regioselectivity is advantageously greater than or equal to 0.25, or 0.30, or 0.35, or 0.40, or 0.45. For the NCO / OH ratio of 1 to 2 in the first step, for example, 1.5 to 1.9 and even more preferably about 1.5, the regioselectivity is advantageously greater than or equal to 0.10, or 0.15, or 0.20, or 0.25 and preferably greater than or equal to 0.30.

[0150] This regional selectivity is due to 13 C1-NMR spectroscopy confirmed that the acquisition conditions allowed for the quantitative integration of peaks C1, C1', C2, and C2' (300 MHz). 1 H, conditions: pulse angle: 30°, relaxation time: 2s, number of scans > 1000).

[0151] During this step, in addition to isophorone diisocyanate, polyols, and guanidine catalysts, one or more other compounds may be present. For example, such other compounds may be solvents, preferably selected from ethyl acetate, acetone, and methyl ethyl ketone.

[0152] This step can be performed at a temperature of 30°C to 120°C, preferably 40°C to 100°C, and even more preferably 50°C to 90°C.

[0153] Alternatively, this step can be carried out for 2 to 10 hours, preferably 2 to 4 hours, using a guanidine-type catalyst according to the invention.

[0154] The prepolymer obtained at the end of this step may have a number average molecular weight of 800 to 20,000 g / mol, preferably 1,000 to 10,000 g / mol, and even more preferably 2,000 to 8,000 g / mol. The molecular weight is measured by size exclusion chromatography using polystyrene as a calibration standard.

[0155] In addition, relative to the total weight of the urethane prepolymer, the urethane prepolymer may have 2 to 20%, preferably 2 to 10%, more preferably 2 to 6% NCO groups by weight.

[0156] For an NCO / OH molar ratio of less than 2, the urethane prepolymer may have a residual monomer content of less than or equal to 5%, preferably less than or equal to 3%.

[0157] The urethane prepolymer may also have a Brookfield viscosity at 23°C measured on day +1, which is 500 to 400,000 mPa·s, preferably 500 to 300,000 mPa·s, more preferably 500 to 200,000 mPa·s, more preferably 500 to 100,000 mPa·s, more preferably 500 to 50,000 mPa·s, more preferably 500 to 25,000 mPa·s, more preferably 500 to 12,000 mPa·s, more preferably 500 to 6,000 mPa·s, more preferably 500 to 3,000 mPa·s, depending on the NCO / OH ratio used and the type of polyol used.

[0158] Step 2 – Formation of polyurethane polymer

[0159] The second step of the method according to the invention is carried out by contacting a urethane prepolymer with at least one second polyol to form a polyurethane polymer. This step is carried out in the presence of a second catalyst.

[0160] The second polyol may be selected from the same polyol as the first polyol previously described.

[0161] According to some implementation schemes, the second polyol may be the same as, different from, or partially different from the first polyol.

[0162] According to some implementation schemes, only one second polyol is contacted with the urethane prepolymer.

[0163] According to other embodiments, more than one second polyol (e.g., two or three second polyols) is contacted with the urethane prepolymer.

[0164] According to a preferred embodiment, the NCO / OH molar ratio in the second step can be 1.3 to 3, preferably 1.5 to 2.

[0165] The second catalyst is a metal catalyst. "Metal catalyst" should be understood as a catalyst containing at least one metal atom.

[0166] According to the preferred embodiment, the metal may be selected from tin, zinc, bismuth, aluminum, titanium, iron, copper and zirconium.

[0167] Preferably, the second catalyst is selected from zinc catalysts, bismuth catalysts, titanium catalysts, iron catalysts, copper catalysts, zirconium catalysts, aluminum catalysts, and combinations thereof. In other words, the second catalyst is preferably tin-free.

[0168] The second catalyst can be a metal carboxylate.

[0169] The carboxylate can be one in which the carboxylic acid contains 2 to 20 carbon atoms, preferably 4 to 14 carbon atoms. Examples of carboxylic acids include: acetic acid, butyric acid, isobutyric acid, hexanoic acid, octanoic acid, 2-ethylhexanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, rosin acid, neodecanoic acid, 2,2,3,5-tetramethylhexanoic acid, 2,4-dimethyl-2-isopropylpentanoic acid, 2,5-dimethyl-2-ethylhexanoic acid, 2,2-dimethyloctanoic acid, 2,2-diethylhexanoic acid, and arachidic acid.

[0170] Carboxylates can be monocarboxylate, dicarboxylate, tricarboxylate, or mixtures thereof.

[0171] Alternatively, the second catalyst can be a metal coordination complex, i.e., a metal complexed with one or more organic ligands. This type of catalyst can be selected from, for example, zinc acetylacetonate, titanium acetylacetonate (e.g., available from Dorf Ketal under the name...). AA75 (commercial purchase), titanium tetraacetylacetonate, aluminum triacetylacetonate, aluminum chelates such as monoacetylacetonate bis(ethyl acetoacetate) (e.g., available from King Industries under the name...) 5218 commercial purchase), zirconium tetraacetylacetonate, titanium diisopropoxybis(ethylpyruvate), zirconium acetylacetonate, copper acetylacetonate and mixtures thereof.

[0172] Alternatively, the second catalyst may be selected from, for example, tin dioctyl dicarboxylate, such as tin dioctyl diacetate, tin dioctyl diethylhexanoate, tin dioctyl dineodecanate (e.g., it may be named TIB). 223 is derived from TIB Chemicals), dioctyl tin dilaurate (DOTL) (e.g., it can be named TIB). 216 is derived from TIBChemicals), dibutyltin dioleate, dibutyltin benzyl maleate, and mixtures thereof.

[0173] According to a preferred embodiment, the second catalyst may be selected from diisopropoxybis(ethyl acetoacetate)titanium, zinc neodecanoate, titanium neodecanoate, iron acetylacetonate, zirconium acetylacetonate, copper acetylacetonate, and mixtures thereof.

[0174] According to some implementation schemes, only one second catalyst is in contact with the urethane prepolymer and the second polyol.

[0175] According to other embodiments, a mixture of multiple second catalysts (e.g., two) is contacted with a urethane prepolymer and a second polyol.

[0176] The second catalyst may be present in a concentration of 100 to 2000 ppm, preferably 200 to 800 ppm, relative to the weight of the OH component.

[0177] During this step, in addition to the urethane prepolymer, the second polyol, and the metal catalyst, one or more other compounds may be present. For example, such other compounds may be solvents, preferably selected from ethyl acetate, acetone, and methyl ethyl ketone.

[0178] During this second step, the contact between the urethane prepolymer and the second polyol and the second catalyst can be carried out by adding the second polyol and the second catalyst to the mixture obtained from the first step that contains the urethane prepolymer.

[0179] The second step can be carried out at a temperature of 15°C to 60°C, preferably at a temperature of 23°C to 50°C.

[0180] Two-component composition

[0181] The present invention also relates to a two-component composition comprising an NCO component and an OH component.

[0182] The NCO component of the composition comprises a urethane prepolymer prepared according to the first step of the above method.

[0183] According to a preferred embodiment, the NCO component corresponds to the mixture obtained after contacting isophorone diisocyanate with a first polyol and a first catalyst. That is, the obtained prepolymer is not separated or purified from the mixture, so the mixture containing the prepolymer and the first catalyst (as well as the residues of the polyol and isophorone diisocyanate) corresponds to the NCO component.

[0184] According to other embodiments, the urethane prepolymer is part of the NCO component of the composition.

[0185] Optionally, one or more additives may be added to the NCO component. These additives may be selected from plasticizers, solvents, pigments, adhesion promoters, hygroscopic agents, UV stabilizers (or antioxidants), molecular sieves, fluorescent materials, rheology modifiers, and mixtures thereof.

[0186] The content of urethane prepolymer relative to the total weight of NCO components can be 60% to 100%, preferably 70% to 99%.

[0187] The additive may be present in an amount of 0 to 10%, preferably 0 to 2%, relative to the weight of the NCO component of the composition.

[0188] The OH component of the composition comprises the second polyol and the second catalyst as described above.

[0189] According to some implementation schemes, only one second polyol exists in the OH component.

[0190] According to other implementation schemes, multiple second polyols (e.g., two, three, four, or five polyols) are present in the OH component.

[0191] The second polyol may be present in an amount of 60% to 100%, preferably 70% to 99%, relative to the total weight of the OH component.

[0192] According to some implementation schemes, only one second catalyst is present in the OH component.

[0193] According to other embodiments, multiple secondary catalysts (e.g., two) are present in the OH component.

[0194] The second catalyst may be present in a concentration of 100 to 2000 ppm, preferably 200 to 800 ppm, relative to the weight of the OH component.

[0195] The OH component according to the invention may also include additives that may be included in the -NCO component, such as plasticizers, solvents, pigments, adhesion promoters, hygroscopic agents, UV stabilizers (or antioxidants), fluorescent materials, rheology additives, and mixtures thereof.

[0196] The additive may be present in an amount of 0 to 10%, preferably 0 to 2%, relative to the weight of the OH component of the composition.

[0197] The NCO and OH components of the two-component composition can preferably be kept separate until the composition is used.

[0198] Use of the composition

[0199] The two-component composition of the present invention can be prepared by mixing the NCO component and the OH component of the composition. During this mixing, the hydroxyl groups present on the second polyol can react with the isocyanate end groups of the urethane prepolymer (in the presence of a second catalyst) to form a polyurethane adhesive.

[0200] The NCO component can be mixed with the OH component at an NCO / OH molar ratio of 1.5 to 2.5, preferably 1.7 to 2.0.

[0201] This two-component composition can be used to treat substrates such as paper, metals such as aluminum, polyethylene (PE), polypropylene (PP), ethylene- and propylene-based copolymers, polyamide (PA), polyethylene terephthalate (PET), or ethylene-based copolymers such as maleic anhydride graft copolymers, copolymers of ethylene and vinyl acetate (EVA), copolymers of ethylene and vinyl alcohol (EVOH), copolymers of ethylene and alkyl acrylates such as methyl acrylate (EMA) or butyl acrylate (EBA), polystyrene (PS), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polymers or copolymers of lactic acid (PLA), or polyhydroxyalkanoates (PHA). Thin layers composed of thermoplastic polymers, preferably PET, PE, and PP, covered with a layer of aluminum, alumina, or silica less than 1 μm in diameter may also be mentioned.

[0202] Before coating the two-component composition (a mixture of NCO and OH components) onto the substrate surface, the OH component of the composition is mixed with the OH component.

[0203] The NCO component can be mixed with the OH component at room temperature, for example at a temperature of 15°C to 60°C, preferably 23°C to 50°C.

[0204] The two-component composition can then be coated onto the surface of the substrate at a temperature of 23 to 50°C, preferably 35 to 40°C.

[0205] This two-component composition can form a continuous layer on the surface of a substrate. The layer may have a thickness of 1 μm to 25 μm, preferably 1 μm to 10 μm, and more preferably 1 μm to 5 μm.

[0206] The two-component composition of the present invention can be used as an adhesive composition to bond two substrates together. Therefore, upon crosslinking, the composition can form an adhesive layer that holds the two substrates together. More specifically, after the two-component composition is coated onto the surface of a substrate, the surface of another substrate can be brought into contact with the coated surface to bond the two substrates. According to some embodiments, when the other substrate is in contact with the coated surface, the assembly can be placed under a hot press to accelerate the bonding of the two substrates together. The temperature of the press can be, for example, 60-110°C, preferably 80-100°C.

[0207] Therefore, an article prepared after applying the composition of the present invention comprises at least one surface coated with the two-component composition. This is the inner surface of the article, i.e., the surface of the article that is in contact with, for example, another surface of the article, and the two-component composition is located between these two surfaces.

[0208] According to some embodiments, the prepared article may comprise more than two layers (or substrates), such as three or four layers (or substrates), which are fixed together using the two-component composition of the present invention.

[0209] Therefore, the two-component composition of the present invention can be used to prepare multilayer films for the preparation of flexible packaging. This type of film can in fact be used to prepare a variety of flexible packages that are shaped and then sealed by heat-sealing (thermal welding) (after the step of packaging products for consumers).

[0210] According to a preferred embodiment, these films are used to prepare flexible packaging for sterilization treatment, such as sterilizing food packaged in the flexible packaging. Example

[0211] The following examples illustrate the present invention but do not limit it.

[0212] The following compounds were used in the examples:

[0213] Vestanat IPDI: Isophorone diisocyanate, sold by Evonik, with a molar weight of 222.6 g / mol and a % NCO content of 37.5-37.8%;

[0214] 1010L: Polypropylene glycol sold by Dow Chemical Company, with a number-average molecular weight of 984 to 1058 g / mol and a hydroxyl value (IOH) of 106 to 114 mg KOH / g.

[0215] CP450: Polypropylene glycol triol sold by Dow Chemical Company, with a number-average molecular weight of 425 to 455 g / mol and a hydroxyl value (IOH) of 370 to 396 mg KOH / g.

[0216] 3008: Aliphatic polyester diols sold by Bostik, with a number-average molecular weight of 967 to 1039 g / mol and a hydroxyl value (IOH) of 108 to 116 mg KOH / g.

[0217] MTBD: 7-Methyl-1,5,7-triazabicyclo[4,4,0]dec-5-ene (CAS No.: 84030-20-6);

[0218] DABCO: 1,4-diazabicyclo[2.2.2]octane (CAS No.: 280-57-9);

[0219] 216: Dioctyltin dilaurate, sold by TIB Chemicals.

[0220] Example 1

[0221] The regioselectivity of the formation process of urethane prepolymers was investigated using different catalysts.

[0222] Therefore, a mixture of 62.4 g Vestanat IPDI, 29.8 g Voranol 1010L, 8.1 g Voranol CP450, and 10 ppm phosphoric acid (to neutralize any trace amounts of catalyst present in the polyol) was contacted at a temperature of 75°C to 78°C, and with various catalysts shown in the table below, until a theoretical % NCO of 18.6% was achieved. This theoretical ratio was determined by calculation based on the composition of the reaction medium and the functionality of the starting materials used.

[0223] The NCO / OH ratio is 4.9.

[0224] The ratio r is calculated using the method detailed in the instruction manual.

[0225] The ratio r corresponds to the regioselectivity associated with isocyanate groups attached to primary carbon atoms versus those attached to secondary carbon atoms, and is calculated according to the method described above. When the catalyst used favors the reaction of isocyanate groups attached to primary carbon atoms (C1), the ratio r is greater than 0, while when the catalyst favors the reaction of isocyanate groups attached to secondary carbon atoms (C2), the ratio r is less than 0. The closer the ratio r is to 0, the lower the regioselectivity of the catalyst.

[0226] The catalyst concentration was adjusted to obtain a reaction similar to that obtained when dioctyltin was used as a catalyst.

[0227]

[0228] DOTL: Dioctyltin dilaurate

[0229] Co(acac)2: Cobalt(II) acetylacetonate

[0230] Zr(acac)4: Zirconium acetylacetonate (IV)

[0231] Fe(OTf)2: Ferric trifluoromethanesulfonate(II)

[0232] BEMP: 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine

[0233] DBN: 1,5-diazabicyclo[4.3.0]non-5-ene

[0234] DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene

[0235] DABCO: 1,4-diazabicyclo[2.2.2]octane

[0236] TBD: 1,5,7-Triazabicyclo[4.4.0]dec-5-ene

[0237] MTBD: 7-Methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene

[0238] Bn-TBD: Benzylated 1,5,7-triazabicyclo[4.4.0]dec-5-ene

[0239] TBO: 1,4,6-Triazabicyclo[3.3.0]oct-4-ene

[0240] MTBO: N-methyl-1,4,6-triazabicyclo[3.3.0]oct-4-ene

[0241] TMG: 1,1,3,3-Tetramethylguanidine

[0242] BTMG: 2-tert-butyl-1,1,3,3-tetramethylguanidine

[0243] Based on the results in the table above, the reaction in the absence of a catalyst (item 1) allows for regioselectivity opposite to that obtained with catalysts of formulas (I) and (II). This reverse regioselectivity can also be obtained using metal catalysts (items 2 to 5) and protonated guanidine catalysts (items 6 and 7), phosphazene catalysts (item 8), and amidine catalysts (item 9). Other catalysts of the amidine (item 10) and tertiary amine (item 11) types allow for regioselectivity in the same direction as with catalysts of formulas (I) and (II), but weaker than the desired regioselectivity. Finally, the use of catalysts according to formulas (I) and (II) (items 12 to 18) allows for the acquisition of urethane prepolymers at a ratio greater than 0.25 r.

[0244] Example 2

[0245] The regioselectivity of the formation process of urethane prepolymers was investigated using different catalysts.

[0246] Therefore, at a temperature between 75°C and 78°C, 23.3 g of Vestanet IPDI was contacted with a mixture of 29.8 g of Voranol 1010 L and 8.1 g of Voranol CP450, along with 10 ppm phosphoric acid (to neutralize any trace amounts of catalyst present in the polyol), and then contacted with the various catalysts shown in the table below until a theoretical % NCO of 6.4% was achieved. This theoretical ratio was determined by calculation based on the composition of the reaction medium and the functionality of the starting materials used.

[0247] The NCO / OH ratio is 1.83.

[0248] As in Example 1, the ratio r was calculated using the method described above. When the catalyst used favors the reaction of isocyanate groups attached to the primary carbon atom (C1), the ratio r is greater than 0, while when the catalyst favors the reaction of isocyanate groups attached to the secondary carbon atom (C2), the ratio r is less than 0. The closer the ratio r is to 0, the lower the regioselectivity of the catalyst.

[0249]

[0250] Ti(acac)2OiPr2: Titanium diisopropoxybisacetylacetate

[0251] Based on the results in the table above, the reaction in the absence of a catalyst (item 1) allows for a regioselectivity opposite to that obtained using catalysts of formulas (I) and (II). This reverse regioselectivity can also be obtained using metal catalysts (items 2 to 5). The tertiary amine type catalyst DABCO (item 6) allows for a regioselectivity in the same direction as that obtained using catalysts of formulas (I) and (II), but weaker than the desired regioselectivity. Finally, the use of catalysts according to formulas (I) and (II) (items 7 and 8) allows for the acquisition of urethane prepolymers at a ratio greater than 0.2 r.

[0252] Example 3

[0253] Three two-component compositions (A to C) were prepared by mixing the NCO component with the OH component. A is the composition according to the present invention, while B and C are comparative compositions.

[0254] The NCO and OH components were prepared in quantities of 100g each.

[0255] The NCO components of each composition were prepared by mixing the components at a temperature of 75 to 78°C. The NCO component of composition A (catalyzed by MTBD) was mixed for 2 to 3 hours, the NCO component of composition C (catalyzed by DOTL) for 2 to 3 hours, and the NCO component of composition B (catalyzed by DABCO) for 32 hours. MTBD here represents the first catalyst according to the invention. The NCO / OH ratio used to synthesize the NCO components of each composition was 1.7.

[0256]

[0257] NCO% was measured using standard NF EN 1242.

[0258]

[0259] The hydroxyl value (IOH) is measured using the ASTM E1899-08 standard.

[0260] The NCO and OH components of compositions A, B, and C are mixed at an NCO / OH molar ratio of 1.86.

[0261] Then use compositions A, B, and C (gram weight 2.5 g / m³). 2 Composites of PET-ALU (20 μm, comprising 12 μm PET + 8 μm aluminum) / adhesive composition (2.5 μm) / PE (50 μm) were prepared, and then these composites were used to measure the crosslinking kinetics of the adhesive composition between the PET-ALU and PE layers over 18 days at 23 °C. The degree of crosslinking of the adhesive composition between the PET-ALU and PE films was measured by infrared spectroscopy by monitoring the disappearance of NCO functional groups on the adhesive film after layering of samples collected daily from the three composites.

[0262]

[0263] Cat 1: First Catalyst

[0264] Cat 2: Second Catalyst

[0265] The results showed that, compared with comparative compositions B and C, the combination Cat 1 / Cat2 = MTBD / DOTL according to the present invention allowed for a significant improvement in the crosslinking kinetics of composition A, with a crosslinking degree greater than or equal to 90% at 10 days.

Claims

1. A method for preparing a polyurethane polymer, comprising: - (A) Contacting at least one isophorone diisocyanate (IPDI) monomer with at least one first polyol in the presence of at least one first catalyst to form a urethane prepolymer; - (B) Contacting a urethane prepolymer with at least one second polyol in the presence of at least one second catalyst to form a polyurethane polymer; in: - The first catalyst is selected from catalysts of general formula (I) or general formula (II): in: - R 0 It is a group containing 1 to 10 carbon atoms, selected from straight-chain or branched alkyl, cycloalkyl, or aralkyl groups. - R 1 R 2 and R 3 Independently representing a group containing 1 to 10 carbon atoms, selected from straight-chain or branched alkyl, cycloalkyl, or aralkyl groups. - R 4 A group representing a hydrogen atom or containing 1 to 10 carbon atoms, selected from straight-chain or branched alkyl, cycloalkyl, aralkyl, or aryl groups. - R 1 R 2 R 3 and R 4 At least two of them are optionally joined in the ring, and - M + Represents a monovalent cation; and – The second catalyst is a metal catalyst.

2. The method according to claim 1, wherein the second catalyst is an organometallic catalyst.

3. The method according to claim 1 or 2, wherein the first and / or second polyol is selected from polyether polyols, polyester polyols and mixtures thereof.

4. The method of claim 3, wherein the first and / or second polyol comprises polypropylene glycol.

5. The method according to any one of claims 1 to 4, wherein the second polyol is the same as the first polyol.

6. The method according to any one of claims 1 to 5, wherein M + Represents Na + cation.

7. The method according to any one of claims 1 to 6, wherein R 0 Selected from methyl or benzyl.

8. The method according to any one of claims 1 to 7, wherein R 1 and R 2 Or R 1 and R 4 It is joined in a ring.

9. The method according to any one of claims 1 to 7, wherein R 1 and R 2 It is joined in the first ring and R 3 and R 4 It is joined in the second ring.

10. The method according to any one of claims 1 to 9, wherein the metal catalyst is selected from tin catalysts, zinc catalysts, bismuth catalysts, titanium catalysts, iron catalysts, copper catalysts, zirconium catalysts, aluminum catalysts, and combinations thereof.

11. The method according to claim 10, wherein the metal catalyst is selected from zinc catalysts, bismuth catalysts, titanium catalysts, iron catalysts, copper catalysts, aluminum catalysts, and zirconium catalysts.

12. The method according to any one of claims 1 to 11, wherein, In the step of contacting at least one isophorone diisocyanate (IPDI) monomer with at least one first polyol, the NCO / OH molar ratio is 1.5 to 5.

13. The method according to any one of claims 1 to 11, wherein, In the step of contacting at least one isophorone diisocyanate (IPDI) monomer with at least one first polyol, the NCO / OH molar ratio is 1.5 to 2.

14. A two-component composition for preparing a polyurethane polymer by the method according to any one of claims 1 to 13, said composition comprising: - NCO component, which contains the urethane prepolymer prepared by step (A) of this method; - and OH components, which contain at least one second polyol and the second catalyst.

15. The composition of claim 14, wherein the NCO component further comprises one or more additives selected from: plasticizers, solvents, pigments, adhesion promoters, hygroscopic agents, UV stabilizers, antioxidants, fluorescent materials, rheology modifiers, and mixtures thereof.

16. The composition according to any one of claims 14 or 15, wherein the NCO / OH molar ratio of the NCO component to the OH component is 1.5 to 2.

5.

17. The composition according to any one of claims 14 or 15, wherein the NCO / OH molar ratio of the NCO component to the OH component is 1.7 to 2.

0.

18. Use of the composition according to any one of claims 14 to 17 as an adhesive for bonding two substrates together.

19. An article comprising at least one layer obtained by crosslinking the composition of any one of claims 14 to 17.

20. A method for preparing the article of claim 19, comprising: - Mix the NCO component and the OH component of the composition; - Apply the mixture to the surface of the substrate; and - This surface is in contact with the surface of another substrate.

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