Amino resin composition with reduced formaldehyde emission

Abstract

An alkylated amino resin composition which is the reaction product of an amino compound, formaldehyde and an alcohol, wherein the alkylated amino resin composition has a free formaldehyde content no greater than 0.15 wt.% based on the total weight of the alkylated amino resin composition, a total content of imino functional groups of at least 0.3 mol per mol of amino compound, a total content of methylol functional groups no greater than 0.3 mol per mol of amino compound, and a monomeric content of alkoxymethoxymethyl groups no greater than 10% based on the monomeric composition of the alkylated amino resin composition.

Description

AMINO RESIN COMPOSITION WITH REDUCED FORMALDEHYDE EMISSIONTechnical Field

[0001] The present invention relates to resin compositions, in particular alkylated amino resin compositions having reduced formaldehyde emission characteristics.Background

[0002] Alkylated amino resins have been used for years in particular in the rubber goods and industrial coating industries. In rubber compositions, alkylated amino resins - such as for example derivatives of amino-l,3,5-triazines - have been used as part of methylene acceptor / donor systems in reinforcing resins or adhesion promoter resins especially in the tire manufacturing industry. In industrial coatings, alkylated amino resins have been used for decades as crosslinking agents which are meant to react with functional groups (usually hydrogen-containing reactive groups) of polymers usually referred to as binder resins.

[0003] Despite the beneficial properties provided by these alkylated amino resins, these have generally the disadvantage of releasing formaldehy de as a volatile by-product under certain conditions or during operational steps. Formaldehyde emission may occur from the presence of residual free formaldehyde in the alkylated amino resins, but also during the manufacturing and usage of these resins, in particular during curing or crosslinking reactions involving such resins. As the emission of formaldehyde is environmentally undesirable and may raise health concerns, it has long been a desire of industry to find acceptable alternative alkylated amino resins and crosslinking systems, which emit no formaldehyde or at least have reduced formaldehyde emission characteristics.

[0004] Partial solutions are described e.g. in US 7,034,086 B2 (Lin et al.) which discloses melamine and guanamine-based crosslinking compositions, and in US 9,605,178 B2 (Gupta et al.) which discloses addition products of a cyclic urea and glyoxal and / or other multifunctional aldehydes that can be used as crosslinkers for coating compositions. Another partial solution is disclosed in US 2020 / 0095453 Al (Weinkoetz et al.) which discloses a process for preparing liquid compositions of etherified melamine formaldehyde resins.

[0005] Without contesting the technical advantages associated with the solutions known in the art, there is still a need for alkylated amino resins having reduced formaldehyde emission characteristics.Summary

[0006] According to one aspect, the present disclosure relates to an alkylated (etherified) amino resin composition which is the reaction product of an amino compound, formaldehyde and an alcohol, wherein the alkylated amino resin composition has a free formaldehyde content no greater than 0. 15 wt.% based on the total weight of the alkylated amino resin composition, a total content of imino functional groups of at least 0.3 mol per mol of amino compound, a total content of methylol functional groups no greater than 0.3 mol per mol of amino compound, and a monomeric content of alkoxymethoxymethyl groups no greater than 10% based on the monomeric composition of the alkylated amino resin composition.

[0007] According to another aspect, the present disclosure is directed to a crosslinking composition comprising an alkylated (etherified) amino resin composition, wherein the crosslinking composition is obtained by contacting an (the) alkylated (etherified) amino resin composition which is the reaction product of an amino compound, formaldehyde and an alcohol, with an aqueous mixture (solution) of a compound (C) capable of (irreversibly) reacting with formaldehyde thereby forming a formaldehyde adduct (A) and (irreversibly) separating the formaldehyde adduct (A) from the crosslinking composition, and wherein the alkylated amino resin composition has a free formaldehyde content no greater than 0. 15 wt.% based on the total weight of the alkylated amino resin composition, and / or wherein the crosslinking composition has a free formaldehyde content no greater than 0. 15 wt.% based on the total weight of the crosslinking composition.

[0008] According to still another aspect, the present disclosure is directed to a curable composition comprising an alkylated amino resin composition or a crosslinking composition as described above.

[0009] In still another aspect of the disclosure, it is provided a method for reducing the free formaldehyde content and / or the formaldehyde emission of an alkylated (etherified) amino resin composition, wherein the method comprises the steps of: a) providing an alkylated amino resin composition which is the reaction product of an amino compound, formaldehyde and an alcohol;b) contacting the alkylated amino resin composition with an aqueous mixture (solution) of a compound (C) capable of (irreversibly) reacting with formaldehyde thereby forming a formaldehyde adduct (A); and c) (irreversibly) separating the formaldehyde adduct (A) from the alkylated amino resin composition; wherein the alkylated amino resin composition after step c), has a free formaldehyde content no greater than 0. 15 wt.% based on the total weight of the alkylated amino resin composition.

[0010] According to yet another aspect, the present disclosure relates to the use of an alkylated amino resin composition or a crosslinking composition as detailed above for the manufacturing of (or in) a curable composition as described above.Detailed description

[0011] According to a first aspect, the present disclosure relates to an alkylated amino resin composition which is the reaction product of an amino compound, formaldehyde and an alcohol, wherein the alky lated amino resin composition has a free formaldehyde content no greater than 0. 15 wt.% based on the total weight of the alkylated amino resin composition, a total content of imino functional groups of at least 0.3 mol per mol of amino compound, a total content of methylol functional groups no greater than 0.3 mol per mol of amino compound, and a monomeric content of alkoxy methoxymethyl groups no greater than 10% based on the monomeric composition of the alkylated amino resin composition.

[0012] In the context of the present disclosure, it has been surprisingly found that a resin composition as described above is characterized by excellent reduced formaldehyde emission characteristics.

[0013] It has no less surprisingly been found that these excellent characteristics are provided even during the manufacturing and usage of the above-described resin composition, in particular during curing or crosslinking reactions involving such resin compositions. The resin composition of the present disclosure is as such particularly suitable for curable compositions, in particular coating compositions.

[0014] These excellent characteristics and attributes are due in particular to the free formaldehyde content, the total content of imino functional groups, the total content of methylol functional groups and the monomeric content of alkoxymethoxymethyl groups beingspecifically controlled and present in the alkylated amino resin composition in the ranges and values as specified above.

[0015] More specifically, it has been surprisingly found that the methylol functional groups present in the alkylated amino resin can act as latent precursors of formaldehyde which may result into unwanted formaldehyde emission over time. Methylol functional groups can indeed decompose into formaldehyde and imino functional groups (also referred to as demethylolation reaction) upon storage. An alkylated amino resin composition having a total content of methylol functional groups which is specifically controlled to be no greater than 0.3 mol per mol of amino compound is then provided with reduced formaldehyde emission characteristics.

[0016] In the context of the present disclosure, it has no less surprisingly been found that alkoxymethoxymethyl groups can also act as latent precursors of formaldehyde which may again result into unwanted formaldehyde emission over time. An alkoxymethoxymethyl group can indeed degrade or decompose into two equivalents of formaldehyde and one equivalent of an imino functional group when the alkylated amino resin is exposed in particular to water, high humidity environment or unfavourable acid-base conditions such as strong basic conditions. An alkylated amino resin composition having a monomeric content of alkoxymethoxymethyl groups which is specifically controlled to be no greater than 10%, based on the monomeric composition of the alkylated amino resin composition, is then further provided with reduced formaldehyde emission characteristics.

[0017] In the context of the present disclosure still, it has further been surprisingly found that imino functional groups present in the alkylated amino resin can act as internal formaldehyde scavengers. Imino functional groups were indeed surprisingly found to have the ability to capture and react with free formaldehyde so as to form stable methylol groups. An alkylated amino resin composition having a total content of imino functional groups of at least 0.3 mol per mol of amino compound is then further provided with reduced formaldehyde emission characteristics.

[0018] This technical approach for reducing formaldehyde emission is seen as particularly counterintuitive and disruptive considering that the approach actually involves actively capturing formaldehyde within the amino resin composition of the present disclosure and leveraging internal formaldehyde scavenging functional sites that were purposefully- introduced.

[0019] The amino resin compositions as described above have been surprisingly found to have excellent structure stability (i.e. they are not prone to unwanted degradation or substantial modification of the resin structure), in particular in neutral to weak basic conditions, which in turn contributes to maintain their excellent characteristics and attributes.

[0020] In the context of the present disclosure, the Applicant successfully managed to formulate an amino resin composition provided with excellent and stable reduced formaldehyde emission characteristics, in particular low free formaldehyde content and high formaldehyde emission reduction performance, not only during the manufacturing but also during the usage of these resin compositions (in particular during curing or crosslinking reactions involving such resins), while providing excellent characteristics and performance attributes such as curing performance, formulation compatibility with solvent-borne and water-borne systems, and film and material properties.

[0021] In the context of the present invention, the term alky lated amino resin is meant to designate a compound or a mixture of compounds resulting from the reaction of an amino compound with formaldehyde thereby forming methylol groups bound to the nitrogen atoms (also typically referred to as a methylolation step), and wherein (at least part of) the methylol groups are further alky lated with an alcohol thereby forming alkylated methylol groups (also referred to as an alkylation step).

[0022] As will be easily apparent to those skilled in the art, the terms “imino functional group”, “methylol functional group” and “alkoxymethoxymethyl group” of the alkylated amino resin have the meaning they conventionally have in the art. The term “imino functional group” is therefore meant to refer to the functional group having the formula ~N-H and derived from an amino site of the amino compound molecule, wherein this functional group is bonded to the rest of the amino compound molecule by what could be referred to as a single bond or a pseudo single bond, and wherein this functional group is typically adjacent to other groups such as methylol, alkoxymethyl and alkoxymethoxymethyl groups. The term “methylol functional group” is meant to refer to the functional group having the formula -N-C ty-OH. wherein this functional group typically results from the reaction between formaldehyde and an amino site of the amino compound molecule, wherein this functional group is bonded to the rest of the amino compound molecule by what could be referred to as a single bond or a pseudo single bond, and wherein this functional group is typically adjacent to other groups such as imino, alkoxymethyl and alkoxymethoxymethyl groups. The term “alkoxymethoxymethyl group” is meant to refer to the functional group having the formula -N-CBty-O-CBty-O-R, wherein this functional groupis bonded to the rest of the amino compound molecule by what could be referred to as a single bond or a pseudo single bond, wherein this functional group typically results from the alkylation of the reaction product formed by the reaction between formaldehyde and an amino site of the amino compound molecule and which is then further reacted with formaldehyde, wherein R is an alky l group, and wherein this group is typically adjacent to other groups such as imino, methylol and alkoxymethyl groups.

[0023] In the context of the present disclosure, the total content of imino functional groups present in the amino resin composition is meant to refer to the total molar content of all the monomeric compounds derived from the alkylated amino resin and containing imino functional groups. Similarly, the total content of methylol functional groups present in the amino resin composition is meant to refer to the total molar content of all the monomeric compounds derived from the alkylated amino resin and containing methylol functional groups.

[0024] The monomeric content of alkoxymethoxymethyl groups present in the monomeric composition of the alkylated amino resin composition is meant to refer to the total content of all the monomeric compounds derived from the alkylated amino resin and containing alkoxymethoxymethyl groups, based on 100% of all the monomeric compounds present in the monomeric composition of the alkylated amino resin composition.

[0025] The content of free formaldehyde present in the alkylated amino resin composition may be measured by conventional titration test methods well know n to those skilled in the art, such as e g. EN ISO 9020 or BS EN 1243:2011. In the context of the present disclosure, the free formaldehyde content is measured using titration test method JIS K 1502: 1993. The total content of imino functional groups, the total content of methylol functional groups and the monomeric content of alkoxymethoxymethyl groups may be measured according to techniques and analytical methods well known to those skilled in the art. In the context of the present disclosure, these values were measured by high-performance liquid chromatography (HPLC) techniques after suitable analysis of the relevant chromatographic monomeric peaks and their respective areas.

[0026] According to a typical aspect, the alky lated amino resin composition of the present disclosure has a free formaldehyde content greater than 0 wt.%, based on the total weight of the alky lated amino resin composition. According to an advantageous aspect, the alkylated amino resin composition of the present disclosure has a free formaldehyde content no greater than 0. 14 wt.%, no greater than 0.13 wt.%, no greater than 0.12 wt.%, no greater than 0.1 1 wt.%, nogreater than 0.10 wt.%, no greater than 0.09 wt.%, no greater than 0.08 wt.%, no greater than 0.07 wt.%, no greater than 0.06 wt.%, no greater than 0.05 wt.%, no greater than 0.045 wt.%, no greater than 0.04 wt.%. no greater than 0.035 wt.%. no greater than 0.03 wt.%, no greater than 0.025 wt.%, no greater than 0.02 wt.%, no greater than 0.015 wt.%, or even no greater than 0.01 wt.%, based on the total weight of the alkylated amino resin composition.

[0027] According to another advantageous aspect, the alkylated amino resin composition as described herein has a total content of imino functional groups of at least 0.4 mol, at least 0.5 mol, at least 0.6 mol, at least 0.7 mol, at least 0.8 mol, at least 0.9 mol, at least 1.0 mol, at least 1.1 mol, at least 1.2 mol. at least 1.3 mol, at least 1.4 mol, or even at least 1.5 mol per mol of amino compound.

[0028] According to still another advantageous aspect of the disclosure, the alkylated amino resin composition has a total content of imino functional groups no greater than 2.0 mol, no greater than 1.9 mol, no greater than 1.8 mol, no greater than 1.7 mol, no greater than 1.6 mol, no greater than 1.5 mol, no greater than 1.4 mol, no greater than 1.3 mol, no greater than 1.2 mol, no greater than 1. 1 mol. or even no greater than 1.0 mol per mol of amino compound.

[0029] According to yet another advantageous aspect, the alkylated amino resin composition has a total content of imino functional groups in a range from 0.3 to 2.0 mol, from 0.3 to 1.8 mol, from 0.3 to 1.6 mol, from 0.3 to 1.5 mol, from 0.3 to 1.4 mol, from 0.3 to 1.3 mol, from 0.3 to 1.2 mol, from 0.3 to 1.1 mol, from 0.3 to 1.0 mol, from 0.4 to 1.0 mol, from 0.5 to 1.0 mol, from 0.6 to 1.0 mol, from 0.7 to 1.0 mol, or even from 0.8 to 1.0 mol per mol of amino compound.

[0030] In yet another advantageous aspect of the disclosure, the alkylated amino resin composition has a total content of imino functional groups in a range from 0.3 to 2.0 mol, from 0.3 to 1.8 mol, from 0.3 to 1.6 mol, from 0.3 to 1.5 mol, from 0.3 to 1.4 mol, from 0.3 to 1.3 mol, from 0.3 to 1.2 mol, from 0.3 to 1.1 mol, from 0.3 to 1.0 mol, from 0.4 to 1.0 mol, from 0.5 to 1.0 mol, from 0.6 to 1.0 mol, from 0.7 to 1.0 mol, or even from 0.8 to 1.0 mol per mol of amino compound.

[0031] In a typical aspect, the alkylated amino resin composition of the present disclosure has a total content of methylol functional groups greater than 0 mol per mol of amino compound. In yet another advantageous aspect, the alk lated amino resin composition has a total content of methylol functional groups no greater than 0.28 mol, no greater than 0.26 mol, no greater than 0.24 mol, no greater than 0.22 mol, no greater than 0.20 mol, no greater than 0. 18 mol, nogreater than 0.16 mol, no greater than 0.14 mol, no greater than 0.12 mol, no greater than 0.10 mol, no greater than 0.09 mol, no greater than 0.08 mol, no greater than 0.07 mol, no greater than 0.06 mol, no greater than 0.05 mol, or even no greater than 0.04 mol per mol of amino compound.

[0032] In yet another beneficial aspect, the alkylated amino resin composition of the present disclosure has a total content of methylol functional groups in a range from 0.01 to 0.30 mol, from 0.01 to 0.25 mol, from 0.01 to 0.20 mol, from 0.01 to 0.18 mol, from 0.01 to 0.16 mol, from 0.01 to 0.14 mol, from 0.01 to 0.12 mol, from 0.01 to 0.10 mol, from 0.01 to 0.09 mol, from 0.01 to 0.08 mol. from 0.01 to 0.07 mol, from 0.01 to 0.06 mol, from 0.02 to 0.06 mol. from 0.02 to 0.05 mol, or even from 0.03 to 0.05 mol per mol of amino compound.

[0033] In a typical aspect, the alkylated amino resin composition of the present disclosure has a monomeric content of alkoxymethoxymethyl groups greater than 0%, based on the monomeric composition of the alkylated amino resin composition. In yet another beneficial aspect, the alkylated amino resin composition as described herein has a monomeric content of alkoxymethoxymethyl groups no greater than 9%, no greater than 8%, no greater than 7%, no greater than 6%, no greater than 5%, no greater than 4%, or even no greater than 3%, based on the monomeric composition of the alkylated amino resin composition.

[0034] According to yet another advantageous aspect, the alky lated amino resin composition has a monomeric content greater than 40 wt.%, greater than 45 wt.%, greater than 50 wt.%, greater than 55 wt.%. greater than 60 wt.%, greater than 65 wt.%, greater than 70 wt.%, greater than 75 wt.%, greater than 80 wt.%, or even greater than 85 wt.%, based on the total weight of the alkylated amino resin composition.

[0035] In the context of the present disclosure, it has been surprisingly found that alkylated amino resin compositions having a monomeric content greater than 40 wt.% are provided with an excellent balance of formulation compatibility7with solvent-home and water-borne systems, and in particular excellent compatibility characteristics in water-borne systems.

[0036] In the context of the present disclosure, the monomeric content is measured by gel permeation chromatography (GPC) according to techniques and methods well known to those skilled in the art.

[0037] According to another aspect, the present disclosure is directed to a crosslinking composition comprising an alkylated amino resin composition, wherein the crosslinking composition is obtained by contacting an alky lated amino resin composition which is thereaction product of an amino compound, formaldehyde and an alcohol, with an aqueous mixture of a compound (C) capable of reacting with formaldehyde thereby forming a formaldehyde adduct (A) and separating the formaldehyde adduct (A) from the crosslinking composition, and wherein the alkylated amino resin composition has a free formaldehyde content no greater than 0.15 wt.% based on the total weight of the alkylated amino resin composition, and / or wherein the crosslinking composition has a free formaldehyde content no greater than 0. 15 wt.% based on the total weight of the crosslinking composition.

[0038] In a typical aspect of the crosslinking composition according to the disclosure, the initial alkylated amino resin composition, i.e. before the steps of contacting it with an aqueous mixture of a compound (C) capable of reacting with formaldehyde thereby forming a formaldehyde adduct (A) and separating the formaldehyde adduct (A) from the crosslinking composition, has a free formaldehyde content greater than 0. 15 wt.% based on the total weight of the alkylated amino resin composition.

[0039] In the context of the present disclosure, it has been surprisingly found that a crosslinking composition as described above and in particular an alkylated amino resin composition obtained as described above are characterized by excellent reduced formaldehyde emission characteristics. It has no less surprisingly been found that these excellent characteristics are provided even during the manufacturing and usage of the above-described amino resin compositions, in particular during curing or crosslinking reactions involving such amino resin compositions.

[0040] These excellent characteristics and attributes are due in particular to the specific actions of a) contacting the alkylated amino resin composition with an aqueous mixture of a compound (C) capable of reacting with formaldehyde thereby forming a formaldehyde adduct (A); and b) separating the formaldehyde adduct (A) from the crosslinking composition. These specific actions are believed to contribute to the forming of an alkylated amino resin composition having advantageous structure and characteristics, which in turn contribute to achieving excellent and stable reduced formaldehyde emission characteristics, in particular low free formaldehyde content and high formaldehyde emission reduction performance, while providing excellent characteristics and performance attributes such as curing performance, formulation compatibility with solvent-borne and water-borne systems, and film and material properties.

[0041] In the context of the present disclosure still it has no less surprisingly been found that the specific action of contacting the alkylated amino resin composition with an aqueous mixture of a compound (C) capable of reacting with formaldehyde thereby forming a formaldehyde adduct (A), does not only allow reducing the content of residual free formaldehyde initially present in the alky lated amino resin, but also allows reducing the total content of methylol functional groups initially present in the alkylated amino resin composition through what can be referred to as a (irreversible) demethylolation reaction, and which goes hand-in-hand with the formation of imino functional groups.

[0042] It is believed that the compound (C) gradually and continuously assists in trapping (through the formation of the formaldehyde adduct (A)) any formaldehyde compound that might be gradually emitted from the amino resin composition upon time. The formation of imino functional groups, which results from the above-detailed demethylolation reaction, is believed to further reduce the free formaldehyde content through the internal formaldehyde scavenging effect detailed hereinbefore, and which results into forming stable methylol groups.

[0043] The demethylolation reaction and the trapping of free formaldehyde assisted by the compound (C) in conjunction with the internal formaldehyde scavenging effect provided by the imino functional groups resulting from the above-detailed demethylolation reaction, are believed to constitute a virtuous and beneficial formaldehyde emission reduction cycle.

[0044] As for the specific action of separating the formaldehyde adduct (A) from the crosslinking composition, it is believed to advantageously affect the above-detailed formaldehyde emission reduction cycle by promoting irreversible demethylolation reactions and irreversible free formaldehyde trapping, and which in turn advantageously impact the overall formaldehyde emission reduction performance of the alkylated amino resin composition and the crosslinking composition.

[0045] This technical approach for reducing formaldehyde emission is seen as particularly counterintuitive and disruptive in at least two aspects, Firstly, because the approach actually involves actively capturing formaldehyde within the amino resin composition of the present disclosure and leveraging internal formaldehyde scavenging functional sites that were purposefully introduced. Secondly, because the technical approach further involves actively releasing and scavenging formaldehyde from latent precursors of formaldehyde (i.e. the methylol functional groups) which are (still) covalently bonded to the backbone of alky lated amino resin.

[0046] The alky lated amino resin compositions obtained as described above have been further surprisingly found to have excellent structure stability, in particular in neutral to weak basic conditions, which in turn contributes to preserve their excellent characteristics and attributes.

[0047] According to an advantageous aspect, the crosslinking composition of the present disclosure is obtained by contacting an alkylated ammo resin which is the reaction product of an amino compound, formaldehyde and an alcohol, with an aqueous solution of the compound (C). The use of an aqueous solution of the compound (C), in particular a homogeneous aqueous solution of the compound (C), has been found to advantageously impact not only the performance of the reaction between the compound (C) and formaldehyde (thereby improving the overall formaldehyde scavenging performance), but also the subsequent action of separating the formaldehyde adduct (A) from the crosslinking composition. These two beneficial effects are believed to advantageously impact the overall formaldehyde emission reduction performance of the alkylated amino resin composition.

[0048] According to another advantageous aspect, the crosslinking composition of the present disclosure is obtained by further irreversibly separating the formaldehyde adduct (A) from the crosslinking composition. The specific action of irreversibly separating the formaldehyde adduct (A) from the crosslinking composition is believed to advantageously impact the overall formaldehyde emission reduction performance of the alkylated amino resin composition.

[0049] In an advantageous aspect of the disclosure, the alky lated amino resin composition comprised in the crosslinking composition has a free formaldehyde content no greater than 0. 14 wt.%. no greater than 0.13 wt.%, no greater than 0.12 wt.%, no greater than 0.11 wt.%, no greater than 0.10 wt.%, no greater than 0.09 wt.%, no greater than 0.08 wt.%, no greater than 0.07 wt.%, no greater than 0.06 wt.%, no greater than 0.05 wt.%, no greater than 0.045 wt.%, no greater than 0.04 wt.%, no greater than 0.035 wt.%, no greater than 0.03 wt.%, no greater than 0.025 wt.%, no greater than 0.02 wt.%, no greater than 0.015 wt.%, or even no greater than 0.01 wt.%, based on the total weight of the alkylated amino resin composition.

[0050] In an advantageous aspect of the disclosure, the crosslinking composition has a free formaldehyde content no greater than 0.14 wt.%, no greater than 0.13 wt.%, no greater than 0.12 wt.%, no greater than 0.11 wt.%, no greater than 0. 10 wt.%, no greater than 0.09 wt.%, no greater than 0.08 wt.%, no greater than 0.07 wt.%, no greater than 0.06 wt.%, no greater than 0.05 wt.%, no greater than 0.045 wt.%, no greater than 0.04 wt.%, no greater than 0.035 wt.%, no greater than 0.03 wt.%, no greater than 0.025 wt.%, no greater than 0.02 wt.%, no greaterthan 0.015 wt.%, or even no greater than 0.01 wt.%, based on the total weight of the crosslinking composition.

[0051] In another advantageous aspect, the alkylated amino resin composition comprised in the crosslinking composition of the disclosure has a total content of imino functional groups of at least 0.3 mol, at least 0.4 mol, at least 0.5 mol, at least 0.6 mol, at least 0.7 mol, at least 0.8 mol, at least 0.9 mol, at least 1.0 mol, at least 1.1 mol, at least 1.2 mol, at least 1.3 mol, at least 1.4 mol, or even at least 1.5 mol per mol of amino compound.

[0052] In another advantageous aspect, the crosslinking composition of the disclosure has a total content of imino functional groups of at least 0.3 mol, at least 0.4 mol, at least 0.5 mol, at least 0.6 mol, at least 0.7 mol, at least 0.8 mol, at least 0.9 mol. at least 1.0 mol, at least 1.1 mol, at least 1.2 mol, at least 1.3 mol, at least 1.4 mol, or even at least 1.5 mol per mol of amino compound.

[0053] In still another advantageous aspect, the alkylated amino resin composition comprised in the crosslinking composition has a total content of imino functional groups no greater than 2.0 mol, no greater than 1.9 mol, no greater than 1.8 mol, no greater than 1.7 mol, no greater than 1.6 mol, no greater than 1.5 mol, no greater than 1.4 mol, no greater than 1.3 mol. no greater than 1.2 mol, no greater than 1. 1 mol, or even no greater than 1.0 mol per mol of amino compound.

[0054] In still another advantageous aspect, the crosslinking composition has a total content of imino functional groups no greater than 2.0 mol, no greater than 1.9 mol, no greater than 1.8 mol, no greater than 1.7 mol, no greater than 1.6 mol, no greater than 1.5 mol, no greater than 1.4 mol, no greater than 1.3 mol, no greater than 1.2 mol. no greater than 1.1 mol, or even no greater than 1.0 mol per mol of amino compound.

[0055] In yet another advantageous aspect, the alkylated amino resin composition comprised in the crosslinking composition has a total content of imino functional groups no greater than 2.0 mol, no greater than 1.9 mol, no greater than 1.8 mol, no greater than 1.7 mol, no greater than 1.6 mol, no greater than 1.5 mol, no greater than 1.4 mol, no greater than 1.3 mol, no greater than 1.2 mol, no greater than 1.1 mol, or even no greater than 1.0 mol per mol of amino compound.

[0056] In yet another advantageous aspect, the crosslinking composition has a total content of imino functional groups no greater than 2.0 mol, no greater than 1.9 mol, no greater than 1.8 mol, no greater than 1.7 mol, no greater than 1.6 mol, no greater than 1.5 mol, no greater than1.4 mol, no greater than 1.3 mol, no greater than 1.2 mol, no greater than 1.1 mol, or even no greater than 1.0 mol per mol of amino compound.

[0057] In yet another advantageous aspect, the crosslinking composition of the disclosure comprises an alkylated amino resin composition having a total content of imino functional groups in a range from 0.3 to 2.0 mol, from 0.3 to 1.8 mol, from 0.3 to 1.6 mol, from 0.3 to 1.5 mol, from 0.3 to 1.4 mol, from 0.3 to 1.3 mol, from 0.3 to 1.2 mol, from 0.3 to 1.1 mol, from 0.3 to 1.0 mol, from 0.4 to 1.0 mol, from 0.5 to 1.0 mol, from 0.6 to 1.0 mol, from 0.7 to 1.0 mol, or even from 0.8 to 1.0 mol per mol of amino compound.

[0058] In yet another advantageous aspect, the crosslinking composition of the disclosure has a total content of imino functional groups in a range from 0.3 to 2.0 mol. from 0.3 to 1.8 mol, from 0.3 to 1.6 mol, from 0.3 to 1.5 mol, from 0.3 to 1.4 mol, from 0.3 to 1.3 mol, from 0.3 to 1.2 mol, from 0.3 to 1.1 mol, from 0.3 to 1.0 mol, from 0.4 to 1.0 mol, from 0.5 to 1.0 mol, from 0.6 to 1.0 mol, from 0.7 to 1.0 mol, or even from 0.8 to 1.0 mol per mol of amino compound.

[0059] In yet another advantageous aspect, the crosslinking composition of the disclosure comprises an alkylated amino resin composition having a total content of methylol functional groups no greater than 0.30 mol, no greater than 0.28 mol, no greater than 0.26 mol, no greater than 0.24 mol, no greater than 0.22 mol, no greater than 0.20 mol, no greater than 0. 18 mol, no greater than 0. 16 mol, no greater than 0. 14 mol, no greater than 0. 12 mol, no greater than 0. 10 mol, no greater than 0.09 mol, no greater than 0.08 mol, no greater than 0.07 mol, no greater than 0.06 mol, no greater than 0.05 mol, or even no greater than 0.04 mol per mol of amino compound.

[0060] In yet another advantageous aspect, the crosslinking composition of the disclosure has a total content of methylol functional groups no greater than 0.30 mol, no greater than 0.28 mol, no greater than 0.26 mol, no greater than 0.24 mol, no greater than 0.22 mol, no greater than 0.20 mol, no greater than 0.18 mol. no greater than 0.16 mol. no greater than 0.14 mol. no greater than 0. 12 mol, no greater than 0. 10 mol. no greater than 0.09 mol, no greater than 0.08 mol, no greater than 0.07 mol, no greater than 0.06 mol, no greater than 0.05 mol, or even no greater than 0.04 mol per mol of amino compound.

[0061] In yet another advantageous aspect, the crosslinking composition of the disclosure comprises an alkylated amino resin composition having a total content of methylol functional groups in a range from 0.01 to 0.30 mol, from 0.01 to 0.25 mol, from 0.01 to 0.2 mol, from 0.01to 0.18 mol, from 0.01 to 0.16 mol, from 0.01 to 0.14 mol, from 0.01 to 0.12 mol, from 0.01 to 0.1 mol, from 0.01 to 0.09 mol. from 0.01 to 0.08 mol, from 0.01 to 0.07 mol, from 0.01 to 0.06 mol, from 0.02 to 0.06 mol, from 0.02 to 0.05 mol. or even from 0.03 to 0.05 mol per mol of amino compound.

[0062] In yet another advantageous aspect, the crosslinking composition of the disclosure has a total content of methylol functional groups in a range from 0.01 to 0.30 mol, from 0.01 to 0.25 mol, from 0.01 to 0.2 mol, from 0.01 to 0.18 mol, from 0.01 to 0.16 mol, from 0.01 to 0.14 mol, from 0.01 to 0.12 mol, from 0.01 to 0.1 mol, from 0.01 to 0.09 mol. from 0.01 to 0.08 mol, from 0.01 to 0.07 mol, from 0.01 to 0.06 mol, from 0.02 to 0.06 mol, from 0.02 to 0.05 mol, or even from 0.03 to 0.05 mol per mol of amino compound.

[0063] In yet another advantageous aspect, the alkylated amino resin composition comprised in the crosslinking composition has a monomeric content of alkoxymethoxymethyl groups no greater than 9%, no greater than 8%, no greater than 7%, no greater than 6%, no greater than 5%, no greater than 4%, or even no greater than 3%, based on the monomeric composition of the alkylated amino resin composition.

[0064] In yet another advantageous aspect, the crosslinking composition has a monomeric content of alkoxymethoxymethyl groups no greater than 9%, no greater than 8%, no greater than 7%, no greater than 6%, no greater than 5%, no greater than 4%, or even no greater than 3%, based on the monomeric composition of the crosslinking composition.

[0065] In yet another advantageous aspect, the alkylated amino resin composition comprised in the crosslinking composition has a monomeric content greater than 40 wt.%, greater than 45 wt.%, greater than 50 wt.%, greater than 55 wt.%. greater than 60 wt.%, greater than 65 wt.%, greater than 70 wt.%, greater than 75 wt.%, greater than 80 wt.%, or even greater than 85 wt.%, based on the total weight of the alkylated amino resin composition.

[0066] In yet another advantageous aspect, the crosslinking composition has a monomeric content greater than 40 wt.%, greater than 45 wt.%, greater than 50 wt.%, greater than 55 wt.%, greater than 60 wt.%, greater than 65 wt.%, greater than 70 wt.%, greater than 75 wt.%, greater than 80 wt.%, or even greater than 85 wt.%, based on the total weight of the crosslinking composition.

[0067] According to another advantageous aspect, the alkylated amino resin composition comprised in the crosslinking composition is further subjected to a re-alkylation treatment of the (residual unreacted) methylol functional groups, which treatment is believed toadvantageously impact the overall formaldehyde emission reduction performance of the alkylated amino resin composition. The re-alkylation treatment of the methylol groups present in the alkylated amino resin may be performed before or after the actions of a) contacting the alkylated amino resin with an aqueous mixture of a compound (C), and b) separating the formaldehyde adduct (A) from the alky lated amino resin. The re-alkylation treatment as described herein contributes to further reduce the content of unalk lated methylol groups in the alk lated amino resin, and therefore advantageously impact the overall formaldehyde emission reduction characteristics of the resulting resin composition. When the re-alkylation treatment is performed after the above-described actions, it is in particular aimed at re-alkylating those methylol groups of the alkylated amino resin which remained unaffected by the demethylolation reaction.

[0068] Compounds (C) for use herein are not particularly limited as long as they are capable of (irreversibly) reacting with formaldehyde thereby (irreversibly) forming a formaldehyde adduct (A) and they are further capable of forming a (stable) aqueous mixture when mixed with water. Compounds (C) for use herein are typically capable of (irreversibly) chemically reacting with formaldehyde through covalent bond formation thereby forming a formaldehyde adduct (A). Accordingly, compounds capable of displacing formaldehyde through (gas) entrainment (like e.g. aqueous or organic solvents such as water or alcohols) do not qualify as compounds (C) for use in the present disclosure. Suitable compounds (C) for use herein will be easily identified by those skilled in the art in the light of the present disclosure. Exemplary compounds (C) for use herein may be commonly referred to in the art as formaldehyde scavengers.

[0069] According to an advantageous aspect, the compound (C) for use herein is capable of irreversibly reacting with formaldehyde thereby irreversibly forming a formaldehyde adduct (A). The use of a compound (C) capable of irreversibly reacting with formaldehyde is believed to further strengthen its formaldehyde scavenging performance, which in turn is believed to advantageously impact the overall formaldehyde emission reduction performance of the alkylated amino resin composition.

[0070] According to an advantageous aspect, the compound (C) for use herein is capable of forming an aqueous solution, in particular a homogeneous (stable) aqueous solution, when mixed with water. As described hereinbefore, such advantageous compounds (C) have been found to advantageously impact not only the performance of the reaction between the compound (C) and formaldehyde, but also the subsequent action of separating the formaldehyde adduct (A) from the crosslinking composition, which in turn are believed to advantageouslyimpact the overall formaldehyde emission reduction performance of the alky lated amino resin composition.

[0071] According to a particular aspect, the compound (C) for use herein is selected from the group of formaldehyde scavengers, in particular from the group of water miscible, water dispersible or water soluble formaldehyde scavengers. Advantageously, the compound (C) for use herein is selected from the group of water soluble formaldehyde scavengers.

[0072] According to an advantageous aspect, the compound (C) for use herein takes the form of a solid salt. The use of a compound (C) in the form of a solid salt has been surprisingly found to provide improved handleability, to enhance the formation of an aqueous mixture comprising such compound (C), in particular a (stable) homogeneous aqueous solution, and to facilitate the action of separating the formaldehyde adduct (A) from the crosslinking composition, in particular according to a liquid-liquid phase separation. These advantageous characteristics are believed to advantageously impact the overall formaldehyde emission reduction performance of the alkylated amino resin composition.

[0073] In an advantageous aspect, the compound (C) for use herein is selected from the group consisting of (alkali metal) sulfite salts, (alkali metal) bisulfite salts, guanidine salts, (alkali metal) cyanurate salts, and any combinations or mixtures thereof.

[0074] In a more advantageous aspect, the compound (C) for use herein is selected from the group consisting of sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium sulfamate, sodium cyanurate, potassium sulfite, potassium bisulfite, potassium metabisulfite, potassium sulfamate, potassium sulfate, potassium carbonate, potassium cyanurate, ammonium sulfite, ammonium bisulfite, ammonium bicarbonate, ammonium carbonate, ammonium sulfamate, ammonium sulfate, ammonium cyanurate, guanidine sulfite, guanidine bisulfite, guanidine metabisulfite, guanidine sulfamate, guanidine sulfate, guanidine carbonate, guanidine hydrochloride, and any combinations or mixtures.

[0075] In a preferred aspect, the compound (C) for use herein is selected from the group consisting of sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium sulfamate, potassium sulfite, potassium bisulfite, potassium metabisulfite, guanidine sulfite, guanidine bisulfite, guanidine metabisulfite, guanidine sulfamate, guanidine sulfate, guanidine carbonate, and any combinations or mixtures.

[0076] In a particularly preferred aspect, the compound (C) for use herein is selected from the group consisting of sodium sulfite, potassium bisulfite, guanidine sulfate, guanidine carbonate, and anv combinations or mixtures.

[0077] Alkylated amino resins for use herein are not particularly limited, as long as they are the reaction product of an amino compound, formaldehyde and an alcohol. Suitable alkylated amino resins for use herein will be easily identified by those skilled in the art in the light of the present disclosure.

[0078] Alky lated amino resins for use herein may be prepared according to methods and techniques well known to those skilled in the art. One exemplary' method for preparing suitable alkylated amino resin is described e.g. in US 7,034,086 B2 (Lin et al.).

[0079] In a typical aspect, the alkylated amino resin comprises alkylated methylol groups.

[0080] Amino compounds for use in the preparation of the alkylated amino resins for use herein are not particularly limited, as long as they are reactive with formaldehyde to form methylol groups bound to the nitrogen atoms (i.e. N-methylol groups) and further reactive with an alcohol. More specifically, the amino compounds for use herein are typically capable of reacting with formaldehyde thereby forming a reaction product comprising methylol groups bound to the nitrogen atoms, and wherein the reaction product is further capable of reacting with an alcohol through an alkylation (or etherification) reaction thereby forming alkylated (or etherified) methylol groups. Suitable amino compounds for use herein will be easily identified by those skilled in the art in the light of the present disclosure.

[0081] According to an exemplary aspect, amino compounds for use herein are selected from the group consisting of amino-l,3,5-triazines and their derivatives, guanamines and their derivatives, ureas and their derivatives, glycoluril, and any combinations or mixtures thereof.

[0082] Guanamine derivatives for use herein include, but are not limited to benzoguanamine, acetoguanamine, and mixtures thereof. Urea derivatives for use herein include, but are not limited to, urea, ethyleneurea, and any mixtures thereof.

[0083] According to an advantageous aspect, the amino compound is selected from the group consisting of melamine, benzoguanamine, acetoguanamine, urea, ethyleneurea, glycoluril, and any combinations or mixtures thereof.

[0084] According to a more advantageous aspect, the amino compound is selected from the group consisting of amino- 1,3, 5 -triazine derivatives; in particular l,3,5-triazine-2-amine, 1,3,5- triazine-2,4-diamine. and l,3,5-triazine-2,4,6-triamine.

[0085] According to a particularly advantageous aspect, the amino compound is selected to be l,3,5-triazine-2,4,6-triamine (also referred to as melamine).

[0086] Alcohols for use in the preparation of the alkylated amino resins for use herein are not particularly limited. Suitable alcohols for use herein will be easily identified by those skilled in the art in the light of the present disclosure.

[0087] In an exemplary aspect, the alcohol for use herein is selected from the group of monohydric alcohols, in particular from the group consisting of methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, tert-butanol, cyclohexanol, phenol, benzy l alcohol, and mixtures thereof.

[0088] In a typical aspect, the alcohol for use herein is selected from the group consisting of monohydric alcohols having from 1 to 6, or even from 1 to 4 carbon atoms.

[0089] Advantageously, the alcohol is selected from the group consisting of methanol, ethanol, propanol, butanol, and any mixtures thereof. More advantageously, the alcohol for use herein is selected from the group consisting of methanol, n-butanol, isobutanol, and any mixtures thereof.

[0090] In an advantageous aspect of the resin composition of the present disclosure, the amino resin is selected from the group consisting of melamine-formaldehyde resins, guanamine- formaldehyde resins, benzoguanamine-formaldehyde resins, acetoguanamine-formaldehyde resins, urea-formaldehyde resins, melamine-urea-formaldehyde resins, glycoluril- formaldehyde resins, and any mixtures thereof.

[0091] In a more advantageous aspect, the amino resin for use herein is selected from the group consisting of melamine-formaldehyde resins, benzoguanamine-formaldehyde resins, and any mixtures thereof.

[0092] In a particularly advantageous aspect, the amino resin for use herein is selected to be a melamine-formaldehyde resin.

[0093] Advantageously, the alkylated amino resin for use herein comprises alkoxymethyl derivatives of melamine, alkoxymethyl derivatives of guanamine, alkoxymethyl derivatives of benzoguanamine, and any mixtures thereof.

[0094] More advantageously, the alkylated amino resin for use herein comprises alkoxymethyl derivatives of melamine, more in particular methoxymethyl derivatives of melamine.

[0095] Advantageously still, the alkylated amino resin for use herein comprises polymethoxymethyl melamine, in particular hexamethoxymethyl melamine, pentamethoxymethyl melamine, tetramethoxymethyl melamine, and any mixtures thereof.

[0096] According to a particular aspect, the amino resin composition or the crosslinking composition of the present disclosure may be adsorbed onto a solid carrier material. This particular form of execution could be particularly beneficial in those applications where a solid state material is more suitable. This is particularly the case in those applications where a solid state resin material would facilitate overall processing, handling and operational steps, such as e.g. in the tire manufacturing industry.

[0097] Solid carrier materials for use herein are not particularly limited. Any carrier material commonly known in the art may be used in the context of the present disclosure. Suitable solid carrier materials for use herein will be easily identified by those skilled in the art in the light of the present disclosure.

[0098] In an advantageous aspect, the solid carrier material for use herein comprises silicates, silica or salts thereof, in particular precipitated silica. Suitable solid carriers for use herein are commercially available from e.g. Evonik Industries under the tradename Sipemat®.

[0099] According to an advantageous aspect, the amino resin composition or the crosslinking composition of the present disclosure has a formaldehyde emission value no greater than 200 ppm, no greater than 180 ppm, no greater than 160 ppm, no greater than 150 ppm, no greater than 140 ppm, no greater than 120 ppm, no greater than 100 ppm, no greater than 90 ppm, no greater than 80 ppm, no greater than 70 ppm, no greater than 60 ppm, no greater than 50 ppm, no greater than 40 ppm, no greater than 30 ppm, or even no greater than 20 ppm, when measured according to the test method described in the experimental section.

[0100] The amino resin composition and the crosslinking composition of the present disclosure are particularly suitable for producing curable compositions, in particular curable coating compositions. In the context of the present disclosure, it has been indeed surprisingly found that the amino resin composition and the crosslinking composition as described herein are particularly suitable for reducing formaldehyde emissions in curable compositions, whilemaintaining the desired performance attributes and properties of the curable composition - in particular its curing performance and characteristics - and / or of the resulting cured composition.

[0101] According to still another aspect, the present disclosure is therefore directed to a curable composition comprising an amino resin composition or a crosslinking composition as described hereinbefore.

[0102] According to a particular aspect, the curable composition of the disclosure further comprises a polymeric binder having active hydrogen groups (or reactive groups).

[0103] Polymeric binders for use herein are not particularly limited. Any polymeric binder commonly known in the art of curable compositions may be used in the context of the present disclosure. Suitable polymeric binders for use herein will be easily identified by those skilled in the art in the light of the present disclosure. Exemplary polymeric binders for use herein are described e.g. in US 7,304.086 B2 (Lin et al.) and in US 9,605,178 B2 (Gupta et al.).

[0104] In an advantageous aspect of the curable composition, the polymeric binder for use herein comprises reactive functionalities selected from the group consisting of hydroxy, carboxy, amino, amido, carbamato, mercapto, or a blocked functionality which is convertible to any of the preceding reactive functionalities.

[0105] In another advantageous aspect, the polymeric binder for use herein is selected from the group of polyfunctional hydroxy group containing materials, such as polyols, hydroxyfunctional acrylic resins having pendant or terminal hydroxy functionalities, hydroxyfunctional polyester resins having pendant or terminal hydroxy functionalities, hydroxyfunctional polyurethane prepolymers, products derived from the condensation of epoxy compounds with an amine, products derived from the condensation of epoxy compounds with an anhydride or a bisphenol, and any mixtures thereof.

[0106] The curable composition as described herein may further comprise additional ingredients which are customary in the art. Exemplary’ ingredients include, but are not limited to, cure catalysts, fillers, light stabilizers, pigments, flow control agents, plasticizers, mold release agents, corrosion inhibitors, rheology' modifiers, solvents, and any' mixtures thereof. As will be easily apparent to those skilled in the art, suitable additional ingredients will depend on the targeted applications and desired performance attributes.

[0107] In a particularly advantageous aspect of the disclosure, the curable composition as described herein is a coating composition, in particular an amino resin coating composition.

[0108] All the particular and advantageous aspects described hereinbefore with respect to the amino resin composition and the crosslinking composition - in particular the alkylated amino resin, the compound (C). the actions of a) contacting the alkylated amino resin with an aqueous mixture of the compound (C), and b) separating the formaldehyde adduct (A) from the alkylated amino resin, and the optional solid carrier material - are fully applicable to the curable composition according to the present disclosure.

[0109] The amino resin composition and the crosslinking composition of the present disclosure are also suitable for producing sulfur-crosslinkable rubber mixtures.

[0110] According to another aspect, the present disclosure is therefore directed to a sulfur- crosslinkable rubber mixture comprising a rubber component and an amino resin composition or a crosslinking composition as described above.

[0111] Rubber components for use herein are not particularly limited. Any rubber component commonly known in the art of sulfur-crosslinkable rubber compositions may be used in the context of the present disclosure. Suitable rubber components for use herein will be easily identified by those skilled in the art in the light of the present disclosure. Exemplary rubber components for use herein are described e.g. in US 2022 / 0041843 Al (Landreau et al.) and in US 2012 / 283360 Al (Veyland et al.).

[0112] In a particular aspect, the rubber component for use herein is a diene elastomer, in particular a diene elastomer selected from the group consisting of polybutadienes, natural rubber, synthetic polyisoprenes, butadiene copolymers, isoprene copolymers, and any mixtures thereof.

[0113] All the particular and advantageous aspects described hereinbefore with respect to the amino resin composition and the crosslinking composition - in particular the alkylated amino resin, the compound (C), the actions of a) contacting the alkylated amino resin with an aqueous mixture of the compound (C), and b) separating the formaldehyde adduct (A) from the alkylated amino resin, and the optional solid carrier material - are fully applicable to the sulfur- crosslinkable rubber mixture according to the present disclosure.

[0114] When used for producing sulfur-crosslinkable rubber mixtures, the amino resin composition or the crosslinking composition of the present disclosure are advantageously adsorbed onto a solid carrier material as described hereinbefore. This particular form of execution is particularly beneficial as it facilitates the overall processing, handling and operational steps associated with the sulfur-crosslinkable rubber mixture.

[0115] In an alternative execution though, the amino resin composition or the crosslinking composition may also be used in a liquid form for producing sulfur-crosslinkable rubber mixtures.

[0116] The sulfur-crosslinkable rubber mixture as described herein may further comprise additional components which are customary in the art. Exemplary components include, but are not limited to, reinforcing agents, vulcanizing agents, curing agents, fillers, and any combinations or mixtures thereof. As will be easily apparent to those skilled in the art, suitable additional components will depend on the targeted applications and desired performance attributes.

[0117] According to another aspect, the present disclosure is directed to a finished or semifinished rubber article comprising a sulfur-crosslinked rubber mixture resulting from the sulfur- crosslinking of a sulfur-crosslinkable rubber mixture as described hereinbefore.

[0118] As will be easily apparent to those skilled in the art, suitable finished or semi-finished rubber articles for use herein may take various shapes, forms, and sizes depending on the targeted applications and desired performance attributes.

[0119] According to an advantageous aspect, the rubber article of the present disclosure is selected from the group consisting of pneumatic vehicle tires, tubes, drive belts, seals, conveyor belts, and any combinations thereof.

[0120] According to a particularly advantageous aspect of the disclosure, the rubber article as described herein is a pneumatic vehicle tire. In the context of the present disclosure, it has been indeed surprisingly found that the amino resin composition and the crosslinking composition as described herein are particularly suitable for reducing formaldehyde emissions in industrial tire manufacturing processes, especially during accelerated handling and compounding processing steps, therefore improving workers safety. Surprisingly still, these reduced formaldehyde emission characteristics are achieved without sacrificing the overall efficiency of the tire production and without detrimentally affecting the desired performance attributes of the resulting pneumatic vehicle tire.

[0121] In another aspect of the disclosure, it is provided a method for reducing the free formaldehyde content and / or the formaldehyde emission of an alkylated amino resin composition, wherein the method comprises the steps of: a) providing an alkylated amino resin composition which is the reaction product of an amino compound, formaldehyde and an alcohol;b) contacting the alkylated amino resin composition with an aqueous mixture of a compound (C) capable of reacting with formaldehyde thereby forming a formaldehyde adduct (A); and c) separating the formaldehyde adduct (A) from the alkylated amino resin composition; wherein the alkylated amino resin composition after step c), has a free formaldehyde content no greater than 0. 15 wt.% based on the total weight of the alkylated amino resin composition.

[0122] In another aspect of the disclosure, it is provided a method of manufacturing an alkylated amino resin composition with reduced formaldehyde emission, wherein the method comprises the steps of: a) allowing an amino compound, formaldehyde and an alcohol to react, thereby forming an alky lated amino resin composition or providing an alkylated amino resin composition which is the reaction product of an amino compound, formaldehyde and an alcohol; b) contacting the alky lated amino resin composition with an aqueous mixture of a compound (C) capable of reacting with formaldehyde thereby forming a formaldehyde adduct (A); and c) separating the formaldehyde adduct (A) from the alkylated amino resin composition; wherein the alkylated amino resin composition after step c), has a free formaldehyde content no greater than 0.15 wt.% based on the total weight of the alkylated amino resin composition.

[0123] All the particular and advantageous aspects described hereinbefore with respect to the alkylated amino resin composition and the crosslinking composition - in particular the alkylated amino resin, the compound (C). the actions of a) contacting the alkylated amino resin composition with an aqueous mixture of the compound (C), and b) separating the formaldehyde adduct (A) from the alkylated amino resin composition, and the optional solid carrier material - are fully applicable to the method for reducing the formaldehyde emission of an alkylated amino resin composition and to the method of manufacturing an alkylated amino resin composition with reduced formaldehyde emission according to the present disclosure.

[0124] According to a typical aspect of the methods as described hereinbefore, the initial alkylated amino resin composition, i.e. before the steps of contacting it with an aqueous mixture of a compound (C) capable of reacting with formaldehyde thereby forming a formaldehyde adduct (A) and separating the formaldehyde adduct (A) from the crosslinking composition, hasa free formaldehyde content greater than 0.15 wt.% based on the total weight of the alky lated amino resin composition.

[0125] According to an advantageous aspect of the methods as described hereinbefore, the alkylated amino resin composition has a free formaldehyde content no greater than 0. 15 wt.%, no greater than 0.14 wt.%, no greater than 0.13 wt.%, no greater than 0.12 wt.%, no greater than 0.11 wt.%, no greater than 0.10 wt.%, no greater than 0.09 wt.%, no greater than 0.08 wt.%, no greater than 0.07 wt.%, no greater than 0.06 wt.%, no greater than 0.05 wt.%, no greater than 0.045 wt.%, no greater than 0.04 wt.%, no greater than 0.035 wt.%, no greater than 0.03 wt.%, no greater than 0.025 wt.%, no greater than 0.02 wt.%, no greater than 0.015 wt.%. or even no greater than 0.01 wt.%, based on the total weight of the alkylated amino resin.

[0126] According to another advantageous aspect of the methods as described hereinbefore, the step of contacting the alkylated amino resin with an aqueous mixture of a compound (C) produces a reaction mixture, and the reaction mixture is subjected to a thermal treatment at a temperature no greater than 100°C, no greater than 90°C, no greater than 85°C, no greater than 80°C. no greater than 75°C, no greater than 70°C. no greater than 65°C, no greater than 60°C. no greater than 55°C, or even no greater than 50°C.

[0127] According to still another advantageous aspect of the methods as described hereinbefore, the reaction mixture is subjected to a thermal treatment at a temperature in a range from 30 to 100°C, from 35 to 90°C, from 40 to 85°C, from 50 to 85°C, from 60 to 85°C, from 65 to 80°C, or even from 75 to 80°C.

[0128] In the context of the present disclosure, it has been surprisingly found that when the reaction mixture is subjected to a thermal treatment at a temperature which is specifically controlled to be within the values and ranges as mentioned hereinbefore, the resulting amino resin (composition) is provided with excellent structure stability (i.e. they are not prone to experience unwanted degradation, side reactions or substantial modification of the resin structure), which in turn contributes to maintain its excellent characteristics and attributes, such as e.g. curing performance, formaldehyde emission reduction performance, formulation compatibility with solvent-home and water-borne systems, and film and material properties.

[0129] Subjecting the reaction mixture to a thermal treatment at a temperature which is specifically controlled to be within the values and ranges as mentioned hereinbefore has also been found to provide an optimum balance of structure stability and efficiency of the reaction between the compound (C) and formaldehyde, and which in turn advantageously impact theoverall formaldehyde emission reduction performance of the resulting alkylated amino resin composition.

[0130] In another advantageous aspect of the methods as described hereinbefore, the aqueous mixture of the compound (C) has a pH no greater than 12, no greater than 11, no greater than10, no greater than 9, no greater than 8, or even no greater than 7, prior to the step of contacting the alkylated amino resin with the aqueous mixture of the compound (C).

[0131] In another advantageous aspect of the methods as described hereinbefore, the aqueous mixture of the compound (C) has a pH in a range from 7 to 12, from 8 to 11, or even from 9 to11 , prior to the step of contacting the alkylated amino resin with the aqueous mixture of the compound (C).

[0132] In still another advantageous aspect of the methods as described hereinbefore, the reaction mixture has (or is actively maintained at) a pH no greater than 12, no greater than 11. no greater than 10, no greater than 9, no greater than 8, or even no greater than 7.

[0133] In yet another advantageous aspect of the methods as described hereinbefore, the reaction mixture has (or is actively maintained at) a pH in a range from 7 to 12, from 8 to 1 1, or even from 9 to 11.

[0134] In the context of the present disclosure, it has been surprisingly found that when the reaction mixture or the aqueous mixture have a pH which is specifically controlled to be within the values and ranges as mentioned hereinbefore, the resulting amino resin composition is provided with excellent structure stability, which in turn contributes to maintain its excellent characteristics and attributes, such as e g. curing performance, formaldehyde emission reduction performance, formulation compatibility with solvent-home and water-borne systems, and film and material properties.

[0135] According to an advantageous aspect of the methods as described hereinbefore, the step of separating the formaldehyde adduct (A) from the alkylated amino resin composition is performed in such manner that the formaldehyde adduct (A) is irreversibly separated from the crosslinking composition.

[0136] In the context of the present disclosure, the step of separating the formaldehyde adduct (A) from the alkylated amino resin composition may be performed according to methods and techniques commonly known to those skilled in the art. Suitable separation methods and techniques for use herein will be easily identified by those skilled in the art in the light of the present disclosure.

[0137] In an advantageous aspect, the step of separating the formaldehyde adduct (A) from the alkylated amino resin composition is performed by a technique selected from the group of liquid-liquid separation, filtration, centrifugation, and any combinations thereof.

[0138] According to the typical aspect of the disclosure according to which the formaldehyde adduct (A) takes the form of a solid state salt, in particular a water-soluble salt, the separation step may be beneficially performed by liquid-liquid separation, in particular by liquid-liquid phase separation between an aqueous phase and organic phase. In that context, the formaldehyde adduct (A) would typically be (fully) dissolved in the aqueous phase, whereas the alkylated amino resin would typically be part (or dissolved into) the organic phase.

[0139] If inadequate separation between the aqueous phase and the organic phase is observed, the addition of hydrophobic organic solvents and / or precipitation-inducing compounds may facilitate or improve the separation. Exemplary precipitation-inducing compounds for use herein may be selected in particular from the group consisting of sodium carbonate, sodium sulfate, and any mixtures thereof. Any residual formaldehyde adduct (A) salts may be removed by conventional physical filtration or centrifugation techniques.

[0140] According to an advantageous aspect of the disclosure, the methods as described hereinbefore further comprise the step of dehydrating the alkylated amino resin composition.

[0141] In the context of the present disclosure, the step of dehydrating the alkylated amino resin composition may be performed according to methods and techniques commonly known to those skilled in the art. Suitable dehydration methods and techniques for use herein will be easily identified by those skilled in the art in the light of the present disclosure.

[0142] In an advantageous aspect, the step of dehydrating the alkylated amino resin composition is performed by a technique selected from the group consisting of vacuum stripping, addition of dehydrating agents, and any mixtures thereof.

[0143] In the context of the present disclosure, it has been surprisingly found that the step of dehydrating the alkylated ammo resin composition is not only beneficial for removing water from the resin, but it also enhances salt crystallization (in particular formaldehyde adduct (A) salts), which in turn improves the efficiency of the step of separating the formaldehyde adduct (A) from the alkylated amino resin composition.

[0144] The step of dehydrating the alkylated amino resin composition by vacuum stripping may be performed according to methods and conditions commonly known to those skilled inthe art. In an exemplary7aspect, the vacuum stripping is performed at a temperature no greater than 120°C under reduced pressure.

[0145] Dehydrating agents for use herein are not particularly limited. Suitable dehydrating agents for use herein will be easily identified by those skilled in the art in the light of the present disclosure. In some cases, the use of dehydrating agents may be preferred over vacuum stripping especially when particularly sensitive alkylated amino resin compositions have to be subjected to a dehydration step.

[0146] According to an advantageous aspect, the dehydrating agents for use herein are selected from the group consisting of sodium carbonate, sodium sulfate, molecular sieves, and any mixtures thereof.

[0147] In the context of the present disclosure, it has been surprisingly found that the use of the selected dehydrating agents as described hereinbefore allows maintaining the treated alkylated amino resin composition in neutral to weak basic conditions and therefore helps preserving its structure stability7, which in turn contributes to maintain its excellent characteristics and attributes.

[0148] An enhanced efficiency of the overall step of separating the formaldehyde adduct (A) from the alky lated amino resin composition is also believed to advantageously impact the overall formaldehyde emission reduction performance of the resulting alkylated amino resin composition.

[0149] According to another advantageous aspect of the disclosure, the methods as described hereinbefore further comprise the step of subjecting the alky lated amino resin composition to a re-alkylation treatment of the (residual unreacted) methylol groups.

[0150] According to still another advantageous aspect of the disclosure, the methods as described hereinbefore further comprise the step of regenerating formaldehyde from the formaldehyde adduct (A).

[0151] According to yet another advantageous aspect of the disclosure, the methods as described hereinbefore further comprise the step of adsorbing the alkylated amino resin onto a solid carrier material, wherein the solid carrier material is in particular as described hereinbefore.

[0152] According to yet another aspect, the present disclosure relates to an alkylated amino resin composition produced by the method for reducing the formaldehyde emission of analkylated amino resin composition or by the method of manufacturing an alky lated amino resin composition with reduced formaldehyde emission as described hereinbefore, and which has in particular a formaldehyde emission value no greater than 200 ppm, no greater than 180 ppm. no greater than 160 ppm, no greater than 150 ppm, no greater than 140 ppm, no greater than 120 ppm, no greater than 100 ppm, no greater than 90 ppm, no greater than 80 ppm, no greater than 70 ppm, no greater than 60 ppm, no greater than 50 ppm, no greater than 40 ppm. no greater than 30 ppm, or even no greater than 20 ppm, when measured according to the test method described in the experimental section.

[0153] All the particular and advantageous aspects described hereinbefore with respect to the alkylated amino resin composition and the crosslinking composition - in particular the alkylated amino resin composition, the compound (C), the actions of a) contacting the alkylated amino resin composition with an aqueous mixture of the compound (C), and b) separating the formaldehyde adduct (A) from the alkylated amino resin composition, and the optional solid earner material - are fully applicable to the alkylated amino resin composition produced by the methods as described hereinbefore.

[0154] According to yet another aspect, the present disclosure relates to the use of an alkylated amino resin composition or a crosslinking composition as detailed above for the manufacturing of (or in) a curable (coating) composition as described hereinbefore.

[0155] According to yet another aspect, the present disclosure relates to the use of an alky lated amino resin composition or a crosslinking composition as detailed above for the manufacturing of (or in) a sulfur-crosslinkable rubber mixture as described hereinbefore.EXAMPLES

[0156] The present disclosure is further illustrated by the following examples. These examples are merely for illustrative purposes only.

[0157] Throughout the present disclosure and example section, the following test and measurement methods are used to characterize the exemplar}' compositions and their performance attributes.Test Methods:A) Free formaldehyde content

[0158] The content of free formaldehyde present in the alkylated amino resin composition is measured using titration test method JIS K 1502: 1993.B) Total content of imino functional groups, total content of methylol functional groups and monomeric content of alkoxymethoxymethyl groups

[0159] The total content of imino functional groups, the total content of methylol functional groups and the monomeric content of alkoxymethoxymethyl groups in the various amino resin compositions is determined by using high-performance liquid chromatography (HPLC) techniques. The amino resin samples are dissolved in a mixture of distilled water and methanol (0.1%-05% wt. / wt.) and analysed using HPLC equipment Shimadzu LC-lOADvp equipped with a photo diode array (PDA) detector and a Osaka Soda (Shiseido) CAPCELL PAK Cl 8 ACR chromatography column. The total content of imino functional groups, the total content of methylol functional groups and the monomeric content of alkoxymethoxymethyl groups are determined by suitable identification of the relevant chromatographic monomeric peaks and calculation of their respective areas.C) Monomeric content

[0010] The monomeric content of the various amino resin compositions is determined by gel permeation chromatography (GPC) techniques. The amino resin samples are dissolved in THF and analysed using GPC equipment Jasco EXTREMA equipped with a refractive index (RI)detector and TOSOH TSKgel columns. The monomeric content is determined by calculation of the area % in the GPC chromatogram.D) Formaldehyde emission analysis

[0161] The formaldehyde emission of curable coating compositions comprising various amino resin compositions is measured according to industrial standard test method GB / T 2912.1-2009 “Textiles - Determination of formaldehyde - Part 1: Free and hydrolyzed formaldehyde water extraction method”Raw materials:

[0162] In the examples, the following raw materials and starting products are used:Melamine is commercially available from Allnex. Referred to hereinafter as MEL.Benzoguanamine is commercially available from TCI chemicals. Referred to hereinafter as BGA.Urea is commercially available from Sigma-Aldrich. Referred to hereinafter as URA.Hexamethyloyl melamine is commercially available from Allnex. Referred to hereinafter as HMM.NaiSCb is sodium sulfite, commercially available from Sigma-Aldrich. Referred to hereinafter as SDS.KHSOs is potassium bisulfite, commercially available from Sigma-Aldrich. Referred to hereinafter as KBS.Guanidine carbonate is commercially available from TCI chemicals. Referred to hereinafter as GCA.Guanidine sulfate is commercially available from TCI chemicals. Referred to hereinafter as GST.Guanidine sulfamate is commercially available from TCI chemicals. Referred to hereinafter as GSM.Guanidine hydrochloride is commercially available from TCI chemicals. Referred to hereinafter as GHC.Cyanuric acid is commercially available from Sigma-Aldrich, and is used to produce sodium cyanurate which will be referred to hereinafter as SCY.Sodium sulfamate is commercially available from TCI chemicals. Referred to hereinafter as SSM.Sodium sulfate is commercially available from TCI chemicals. Referred to hereinafter as SSA.Ammonium nitrate is commercially available from TCI chemicals. Referred to hereinafter as AMN.Cymel® 1158 is a hexamethoxymethyl melamine-based melamine resin, commercially available from Allnex. Referred to hereinafter as CYM-1158.Cymel® 325 is a hexamethoxymethyl melamine-based melamine resin, commercially available from Allnex. Referred to hereinafter as CYM-325.Examples:Example 1 : Procedure for the preparation of the amino resin composition of Ex, 1 ,

[0163] A 50% formalin solution (1536 g) is added into a reaction vessel under stirring and pH is adjusted to 9.0 with addition of an alkaline solution. Melamine (302 g) is then added to the reaction vessel and the reaction mixture is heated to 95°C and kept under stirring for 15 minutes to perform the methylolation reaction. The solvent is removed under reduced pressure. Methanol (2304 g) and an acid solution are added to the reaction vessel and the reaction mixture is heated to 65°C and kept under stirring for 40 minutes at a pH of 2.7 to perform a first methylation reaction. The pH of the reaction mixture is then adjusted at 11 by addition of an alkaline solution. Melamine (200 g) is added to the reaction vessel and the solvent is removed under reduced pressure. Methanol (2176 g) is then added to the reaction vessel and a second methylation reaction is performed at 65°C and a pH of 5.0 for 30 minutes. The pH of the reaction mixture is then adjusted at 11 by addition of an alkaline solution and the solvent is removed by heating under reduced pressure. Methanol (2176 g) is then added to the reaction vessel and a third methylation reaction is performed at 65°C and a pH of 4.8 for 30 minutes. The pH of the reaction mixture is then adjusted at 11 by addition of an alkaline solution and the solvents are then removed under reduced pressure. A sodium sulfite solution prepared by mixing sodium sulfite (230 g) with water (826 g) is then added to the reaction vessel and thereaction mixture is heated to 75°C and kept under stirring for 2 hours to perform the formaldehyde scavenging reaction. The reaction mixture is then transferred into a separatory funnel and left for 45 minutes for liquid-liquid separation. The aqueous layer is disposed and the resin layer is transferred back into the reaction vessel for thermal stripping under reduced pressure of the residual water. The resin is diluted with n-butanol (200 g) and filtered, resulting in a clear resin product.Example 2: General procedure for the preparation of the amino resin compositions of Ex, 2 to Ex,9 and the comparative amino resin compositions of Ex.Cl to Ex,C3,

[0164] HMM, methanol and an acid solution are added into a reaction vessel under stirring and the reaction mixture is heated to 70°C and kept under stirring for 20 minutes at a pH of 2.7 to perform the methylation reaction. The pH of the reaction mixture is then adjusted at 10-11 by addition of an alkaline solution and the solvents are then removed under reduced pressure. An aqueous mixture of the compound (C) is then added to the reaction vessel and the reaction mixture is heated to 75-80°C and kept under stirring for 2 hours to perform the formaldehyde scavenging reaction. The reaction mixture is then transferred to a separatory’ funnel and left for 45 minutes for liquid-liquid separation. The aqueous layer is disposed and the resin layer is transferred back into the reaction vessel for thermal stripping under reduced pressure of the residual w ater. The resin is diluted with n-butanol or iso-butanol to obtain a non-volatile content of 85-90% and then filtered, resulting in a clear resin product.

[0165] Regarding specifically the amino resin composition of Ex.7, the separation of the formaldehyde adduct is not performed by liquid-liquid separation but by filtration with glass fiber filter paper.

[0166] Regarding specifically the comparative resin composition of Ex.Cl, the preparation procedure is as detailed hereinbefore at the exception that no treatment w ith an aqueous mixture of a compound (C) is used.

[0167] Regarding specifically the comparative resin composition of Ex.C3, the preparation procedure is as detailed hereinbefore at the exception that premature gelation occurred during the treatment with an aqueous mixture.Example 3: Formulation of exemplary amino resin compositions (Ex. l to Ex,9) and comparative amino resin compositions (Ex.Cl to Ex,C3).

[0168] The general formulation of exemplary' amino resin compositions and comparative amino resin composition are presented in Table 1 below. In Table 1 are specified the compound (C) used in the aqueous mixture for treating the exemplary amino resin compositions. The comparative amino resin composition of Ex. Cl has not been treated with any compound (C). The comparative amino resin compositions of Ex.C2 and Ex.C3 have been treated with a compound which is not a compound (C) for use herein.Table 1: Formulation of exemplary amino resin compositions (Ex. l to Ex.9) and comparative amino resin compositions (Ex. Cl to Ex.C3).Table 1 (continued):Example 4 Structural analysis and free formaldehyde content

[0169] The total content of imino functional groups, the total content of methylol functional groups and the monomeric content of alkoxymethoxymethyl groups, as well as the free formaldehyde content in exemplary amino resin compositions (Ex. l to Ex.9) and comparative amino resin compositions (Ex. Cl to Ex.C3) are determined according to the test method described hereinbefore. The results are presented in Table 2 below.Table 2: Structural analysis and free formaldehyde content of various exemplary amino resin compositions and comparative amino resin compositions.Table 2 (continued):N / D*: not determined due to premature gelation.

[0170] As can be seen from the results shown in Table 2 above, the total content of methylol functional groups and the free formaldehyde content in amino resin compositions according to the present disclosure (Ex. l to Ex.9) is reduced when compared to amino resin compositions not according to the present disclosure (Ex. Cl to Ex.C2). It can further be observed that amino resin compositions according to the present disclosure (Ex. l to Ex.9) have a total content of imino functional groups which is higher than in an amino resin compositions not according to the present disclosure (Ex.Cl to Ex.C2). The comparative amino resin composition of Ex.C3 could not be treated with an aqueous mixture and therefore no meaningful measurements could be performed.Example 5: Formaldehyde emission characteristics of coating compositions

[0171] Two exemplary coating compositions and comparative coating composition are prepared by combining various amino resin compositions (8 parts by weight) with a diisocyanate (12 parts by weight) and with a conventional solvent borne alkyd / polyester binder (80 parts by weight). The coating compositions are then coated on a synthetic textile substrate and thermally cured according to a conventional procedure.

[0172] The formaldehyde emission characteristics (expressed in ppm) of the various exemplary coating compositions and the comparative coating compositions are determined according to the test method described hereinbefore. The results are presented in Table 3 below. In Table 3 are specified the corresponding alkylated amino resins used for the preparation of the exemplary coating compositions and the comparative coating compositions.Table 3: Formaldehyde emission characteristics of various exemplary' coating compositions and comparative coating compositions.

[0173] As can be seen from the results shown in Table 3 above, the formaldehyde emission of coating compositions produced with amino resin compositions according to the present disclosure (Ex.l and Ex.2) is substantially reduced when compared to coating compositions produced with amino resin compositions not according to the present disclosure (CYM-1158 and CYM-325).Example 6: Procedure for the preparation of the amino resin composition of Ex, 10,

[0174] A 44% formalin solution (204 g) is added into a reaction vessel under stirring and pH is adjusted to 9.4 w ith addition of an alkaline solution. Benzoguanamine (187 g) and methanol (32 g) are then added to the reaction vessel and the reaction mixture is heated to 80°C and kept under stirring for 10 minutes. Methanol (256 g) and an acid solution are added to the reaction vessel and the reaction mixture is heated to 55°C and kept under stirring for 60 minutes at a pH of 4.6. The pH of the reaction mixture is then adjusted at 10 by addition of an alkaline solutionand the solvent is removed by heating under reduced pressure. Methanol (480 g) is then added to the reaction vessel and the temperature adjusted to 45°C. An acid solution is added to start the reaction with methanol. The temperature is 45°C and the pH is 5.0. The solvent is removed by hearing under reduced pressure. A sodium sulfite solution prepared by mixing sodium sulfite (57 g) with water (170 g) is then added to the reaction vessel and the reaction mixture is heated to 75°C and kept under stirring for 2 hours to perform the formaldehyde scavenging reaction. The reaction mixture is then transferred into a separatory funnel and left for 60 minutes for liquid-liquid separation. The aqueous layer is disposed and the resin layer is transferred back into the reaction vessel for thermal stripping under reduced pressure of the residual water. The resin is diluted with n-butanol (50 g) and filtered, resulting in a clear resin product.of the amino resinof Ex.l l.

[0175] A 44% formalin solution (204 g) is added into a reaction vessel under stirring and pH is adjusted to 9.6 with addition of an alkaline solution. Urea (121 g) is then added to the reaction vessel and the reaction mixture is heated to 85°C and kept under stirring for 15 minutes. Butanol (512 g) is then added and the temperature is adjusted to 50°C. An acid solution is added to the reaction vessel to start the first butyl ati on. and the reaction mixture is heated to 55°C and kept under stirring for 60 minutes at a pH of 2.5. The water part of the distillates is removed and the butanol part is returned to the reactor to reduce the water content in the mixture. After 2 hours, the pH of the reaction mixture is then adjusted at 9 by addition of an alkaline solution and the solvent is removed by heating under reduced pressure. Butanol (512 g) is then added and the temperature is adjusted to 50°C. An acid solution is then added to start the reaction the second butylation reaction. The temperature is controlled to 55°C and the pH is 1.2. The solvent is removed by heating under reduced pressure. The water part of the distillates is removed and the butanol part is returned to the reactor to reduce the water content in the mixture. After 2 hours, the pH of the reaction mixture is then adjusted at 9 by addition of an alkaline solution and the solvent is removed by heating under reduced pressure. A sodium sulfite solution prepared by mixing sodium sulfite (57 g) with water (170 g) is then added to the reaction vessel and the reaction mixture is heated to 75°C and kept under stirring for 2 hours to perform the formaldehyde scavenging reaction. The reaction mixture is then transferred into a separatory funnel and left for 60 minutes for liquid-liquid separation. The aqueous layer is disposed and the resin layer is transferred back into the reaction vessel for thermal stripping under reducedpressure of the residual water. The resin is diluted with n-butanol (50 g) and filtered, resulting in a clear resin product.Example 8: Structural analysis and free formaldehyde content (Ex, 10 and Ex. l 1),

[0176] The total content of imino functional groups, the total content of methylol functional groups and the monomeric content of alkoxymethoxymethyl groups, as well as the free formaldehyde content in exemplary' amino resin compositions (Ex. 10 and Ex. 11) are determined according to the test method described hereinbefore. The results are presented in Table 4 below.Table 4: Structural analysis and free formaldehyde content of exemplary amino resin compositions (Ex. 10 and Ex. 11).

[0177] As can be seen from the results shown in Table 4 above, the amino resin compositions according to the present disclosure (Ex. 10 and Ex. 11) are provided with excellent characteristics as regard to the free formaldehyde content, the total content of imino functional groups, the total content of methylol functional groups and the monomeric content of alkoxymethoxymethyl groups.

Claims

CLAIMS1. An alkylated amino resin composition which is the reaction product of an amino compound, formaldehyde and an alcohol, wherein the alkylated amino resin composition has a free formaldehyde content no greater than 0.15 wt.% based on the total weight of the alkylated amino resin composition, a total content of imino functional groups of at least 0.3 mol per mol of amino compound, a total content of methylol functional groups no greater than 0.3 mol per mol of amino compound, and a monomeric content of alkoxymethoxymethyl groups no greater than 10% based on the monomeric composition of the alkylated amino resin composition.

2. A resin composition according to claim 1, which has a free formaldehyde content no greater than 0.14 wt.%, no greater than 0.13 wt.%, no greater than 0. 12 wt.%, no greater than 0.11 wt.%, no greater than 0.10 wt.%, no greater than 0.09 wt.%, no greater than 0.08 wt.%, no greater than 0.07 wt.%, no greater than 0.06 wt.%, no greater than 0.05 wt.%. no greater than 0.045 wt.%, no greater than 0.04 wt.%. no greater than 0.035 wt.%, no greater than 0.03 wt.%, no greater than 0.025 wt.%, no greater than 0.02 wt.%, no greater than 0.015 wt.%, or even no greater than 0.01 wt.%, based on the total weight of the alkylated amino resin composition.

3. A crosslinking composition comprising an alkylated amino resin composition, wherein the crosslinking composition is obtained by contacting an alkylated amino resin composition which is the reaction product of an amino compound, formaldehyde and an alcohol, with an aqueous mixture of a compound (C) capable of reacting with formaldehyde thereby forming a formaldehyde adduct (A) and separating the formaldehyde adduct (A) from the crosslinking composition, and wherein the alkylated amino resin composition has a free formaldehyde content no greater than 0.15 wt.% based on the total w eight of the alkylated amino resin composition, and / or wherein the crosslinking composition has a free formaldehyde content no greater than 0.15 wt.% based on the total weight of the crosslinking composition.

4. A crosslinking composition according to claim 3, wherein the alkylated amino resin composition has a free formaldehyde content no greater than 0. 14 wt.%, no greater than 0. 13 wt.%, no greater than 0. 12 wt.%, no greater than 0. 11 wt.%. no greater than 0. 10wt.%, no greater than 0.09 wt.%, no greater than 0.08 wt.%, no greater than 0.07 wt.%, no greater than 0.06 wt.%, no greater than 0.05 wt.%, no greater than 0.045 wt.%, no greater than 0.04 wt.%, no greater than 0.035 wt.%, no greater than 0.03 wt.%. no greater than 0.025 wt.%, no greater than 0.02 wt.%, no greater than 0.015 wt.%, or even no greater than 0.01 wt.%, based on the total weight of the alkylated amino resin composition.

5. A crosslinking composition according to any one of claim 3 or 4, wherein the compound (C) is selected from the group consisting of sulfite salts, bisulfite salts, guanidine salts, cyanurate salts, and any combinations or mixtures thereof.

6. A crosslinking composition according to any one of claims 3 to 5. wherein the compound (C) is selected from the group consisting of sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium sulfamate, guanidine sulfite, guanidine bisulfite, guanidine metabisulfite, guanidine sulfamate, guanidine sulfate, guanidine carbonate, and any combinations or mixtures.

7. A composition according to any one of the preceding claims, wherein the amino compound is selected from the group consisting of amino-1,3,5- triazines, guanamines, ureas, glycoluril, and any combinations or mixtures thereof.

8. A composition according to any of the preceding claims, which has a formaldehyde emission value no greater than 200 ppm, no greater than 180 ppm, no greater than 160 ppm, no greater than 150 ppm. no greater than 140 ppm, no greater than 120 ppm, no greater than 100 ppm, no greater than 90 ppm. no greater than 80 ppm, no greater than 70 ppm, no greater than 60 ppm, no greater than 50 ppm, no greater than 40 ppm, no greater than 30 ppm, or even no greater than 20 ppm, when measured according to the test method described in the experimental section.

9. A curable composition comprising an alkylated amino resin composition or a crosslinking composition according to any one of the preceding claims.

10. A method for reducing the free formaldehyde content and / or the formaldehyde emission of an alkylated amino resin composition, wherein the method comprises the steps of:a) providing an alkylated amino resin composition which is the reaction product of an amino compound, formaldehyde and an alcohol; b) contacting the alkylated amino resin composition with an aqueous mixture of a compound (C) capable of reacting with formaldehyde thereby forming a formaldehyde adduct (A); and c) separating the formaldehyde adduct (A) from the alkylated amino resin composition; wherein the alkylated amino resin composition after step c), has a free formaldehyde content no greater than 0. 15 wt.% based on the total weight of the alky lated amino resin composition.

11. A method according to claim 10, wherein the step of contacting the alkylated amino resin with an aqueous mixture of a compound (C) produces a reaction mixture, and wherein the reaction mixture is subjected to a thermal treatment at a temperature no greater than 100°C, no greater than 90°C, no greater than 85°C, no greater than 80°C, no greater than 75°C. no greater than 70°C, no greater than 65°C, no greater than 60°C, no greater than 55°C, or even no greater than 50°C.

12. A method according to any of claim 10 or 11, wherein the aqueous mixture has a pH no greater than 12, no greater than 11, no greater than 10, no greater than 9, no greater than 8. or even no greater than 7.

13. A method according to any one of claims 10 to 12, wherein the step of separating the formaldehyde adduct (A) from the alkylated amino resin is performed by any of liquidliquid separation, filtration or centrifugation.

14. A method according to any one of claims 10 to 13, which further comprises the step of dehydrating the alkylated amino resin, wherein the dehydration step is performed byvacuum stripping and / or by using dehydrating agents.

15. Use of an alkylated amino resin composition or a crosslinking composition as described in any one of claims 1 to 8 for the manufacturing of a curable composition, in particular a curable coating composition.