Moisture-curable composition

Abstract

The present invention relates to a moisture-curable composition comprising: at least one silyl-modified polymer (A); at least one organofunctional silane compound (B) having at least one amino group and a hydrolyzable silyl group; and at least one flame retardant component (C) comprising a halogen-free nitrogen and phosphorus flame retardant. The invention further relates to the use of said moisture-curable composition as a sealant, as an adhesive, or as a coating, and to an article comprising at least one layer obtained by curing said moisture-curable composition.

Description

Technical Field

[0001] The invention relates to a moisture-curing composition. The invention also relates to the use of the moisture-curing composition as a sealant, as an adhesive or as a coating, and to an article comprising at least one layer obtained by curing the moisture-curing composition. Background Art

[0002] Sealing (or sealant or caulk) compositions are widely used in the construction sector. They are implemented for assembling substrates, for example made of concrete, via expansion joints. In such uses, they make it possible, by virtue of their mechanical and in particular elastic properties, to obtain joints that are stable with respect to dimensional changes caused by temperature changes. Sealant compositions can also be used for the adhesive bonding of floor coverings, in particular wooden floors.

[0003] For manual use purposes, the sealant composition is generally packaged in a cartridge having a nozzle at one end, which is applied after the cartridge is placed in a gun. The operator's operation of the gun trigger actuates a piston, which extrude the sealant through the nozzle onto one of the substrates to be assembled and / or introduces it into a gap between two substrates to be joined.

[0004] The sealant composition comprises a moisture crosslinkable prepolymer having a chemical structure having isocyanate or alkoxysilyl reactive groups which are typically terminal.

[0005] After extruding the sealant onto the substrate to make the assembly and / or after extruding the sealant into the gap between two substrates to be filled, these reactive groups undergo a crosslinking or curing reaction with water from air moisture or from substrate moisture. This reaction results in the production of a solid three-dimensional polymer network including, for example, siloxane bonds, which forms a cohesive joint between the two substrates.

[0006] Silylated sealing compositions are known in particular in industrial sectors such as the transport and construction industries.

[0007] In the transportation industry, especially for trains and high-speed trains, extremely good flame retardant properties of seals are required. For example, in the railway field, there are various fire safety standards to ensure the safety of people and equipment in railway applications. In such standards, different components assembled in train carriages need to have extreme oxygen indices according to different fire safety levels.

[0008] In traditional flame retardant compositions, halogen-free flame retardants are increasingly replacing toxic halogenated flame retardants, as the latter are subject to strict regulations for use due to environmental and health considerations. However, halogen-free flame retardants are inferior to halogenated flame retardants in flame retardant properties and are very difficult to achieve high flame retardant requirements, especially high oxygen index.

[0009] For example, organic phosphorus and phosphorus nitrogen flame retardants are known to be very effective halogen-free flame retardants, and they have high thermal stability and low load compared with other types of halogen-free flame retardants. However, when used in adhesive or sealant systems, such flame retardants still have insurmountable defects. For example, a flame retardant containing phosphorus is an acidic compound, which has a low pH value due to the use of phosphoric acid in its synthesis and process. Since the phosphorus content in the flame retardant is one of the key factors determining its flame retardancy, a low pH value is essential for maintaining the good flame retardant properties of such phosphorus-based flame retardants. On the other hand, many commonly used adhesive or sealant systems require alkaline conditions for curing, such as two-component (2K) epoxy systems, polyurethane systems generally using amines as reaction catalysts, and silyl-modified polymers and their compounded adhesives or sealants. Therefore, using an acidic flame retardant composition in such an adhesive or sealant system will slow down or even block the curing reaction, which will also weaken the mechanical properties of the cured adhesive or sealant.

[0010] Document US 2008 / 0241529 relates to fireproof adhesives and sealants containing 0.1-99.9% by weight of an adhesive or a thermoplastic polymer and 0.1-99.9% by weight of a fireproofing agent, wherein the fireproofing agent contains at least one phosphinate and / or one diphosphinate.

[0011] Document EP3878909 relates to a moisture-curable silylated composition comprising 35 to 65% by weight of a polymer (A) comprising at least 2 alkoxysilyl end groups; 2.5 to 12% by weight of a polymer (B) comprising at least 2 alkoxysilyl end groups; and 7.5 to 28% by weight of an alkoxy-modified silsesquioxane (C). The moisture-curable silylated composition also comprises a phosphoric acid ester or a derivative of a phosphoric acid ester, such as tris(2-ethylhexyl) phosphate, as a flame retardant in an amount ranging from 10 to 20% by weight.

[0012] Document CN102203186A relates to a flame retardant polyurethane composition, which comprises (a) a resin component based on thermoplastic polyurethane, (b) a phosphorus flame retardant particle filler, and (c) a low melting temperature phosphorus flame retardant.

[0013] Document CN103333653A relates to a flame retardant single-component modified silane (MS) polyether sealant and a preparation method thereof. The sealant comprises an MS premix, a crosslinking agent, a coupling agent and a catalyst. The MS premix consists of an MS polymer resin, a plasticizer, a flame retardant filler, a reinforcing filler, a thixotropic agent and a performance enhancer. The flame retardant filler is aluminum hydroxide, magnesium hydroxide, antimony trioxide, zinc borate, zinc carbonate, melamine cyanurate, chloroplatinic acid, a platinum complex, benzotriazole, melamine salt, or a combination thereof.

[0014] Other flame-retardant one-component silane-modified polyether sealants are known from the documents CN102660214A, CN103320079A and CN105255431A.

[0015] There remains a need for moisture curable adhesive or sealant compositions that can provide good flame retardant properties without compromising cure speed or efficiency and thus the mechanical properties of the adhesive / sealant. Summary of the invention

[0016] A first object of the present invention is to provide a moisture-curable composition comprising:

[0017] - at least one silyl-modified polymer (A);

[0018] - at least one organofunctional silane compound (B) having at least one amino group and a hydrolyzable silyl group; and

[0019] - at least one flame retardant component (C) comprising a halogen-free nitrogen-phosphorus flame retardant.

[0020] According to some embodiments, the moisture-curable composition comprises:

[0021] - 30 to 60 parts by mass of a silyl-modified polymer (A);

[0022] - 0.2 to 3 parts by mass of an organofunctional silane compound (B); and

[0023] - 20 to 50 parts by mass of a flame retardant component (C).

[0024] According to some embodiments, the halogen-free nitrogen-phosphorus flame retardant comprises one or more selected from piperazine polyphosphate (PAPP), piperazine phosphate, melamine polyphosphate (MPP), melamine cyanurate (MCA) and ammonium polyphosphate (APP), preferably, the halogen-free nitrogen-phosphorus flame retardant comprises PAPP. Preferably, PAPP comprises or is piperazine pyrophosphate.

[0025] According to some embodiments, the flame retardant component (C) comprises 25 to 100 mass % of piperazine polyphosphate (PAPP) and 0 to 75 mass % of at least one flame retardant other than PAPP, based on the total weight of the flame retardant component (C).

[0026] According to some embodiments, the at least one flame retardant other than PAPP is a nitrogen-phosphorus flame retardant, a nitrogen flame retardant, a phosphorus flame retardant, a metal oxide flame retardant, a metal hydroxide flame retardant, or a combination thereof.

[0027] According to some embodiments, the organofunctional silane compound (B) has two or more amino groups.

[0028] According to some embodiments, the hydrolyzable silyl group of the organofunctional silane compound (B) has the formula -SiXYZ, wherein X, Y and Z are independently selected from hydrogen, C1-C8 alkyl and C1-C8 alkoxy, and at least one of X, Y or Z is a hydrolyzable group.

[0029] According to some embodiments, the hydrolyzable group for at least one of X, Y and Z is a C1-C8 alkoxy group.

[0030] According to some embodiments, the organofunctional silane compound (B) has the formula XYZSi-A-NH-(B-NH) z -H, z is an integer from 0 to 4, and A and B are divalent alkyl groups.

[0031] According to some embodiments, the organofunctional silane compound (B) comprises an aminoalkylalkoxysilane selected from the group consisting of:

[0032] 3-(Trimethoxysilyl)propylamine having the formula:

[0033]

[0034] [3-(2-aminoethylamino)propyl]trimethoxysilane having the formula:

[0035] and

[0036] 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane having the formula:

[0037]

[0038] According to some embodiments, the silyl-modified polymer (A) comprises one or more selected from silyl-modified polyethers and silyl-modified polyurethanes.

[0039] According to some embodiments, the moisture-curable composition further comprises a curing catalyst (D).

[0040] According to some embodiments, the moisture-curable composition further comprises at least one additive selected from the group consisting of solvents, pigments, dyes, adhesion promoters, desiccants, molecular sieves, antioxidants, wetting agents, UV absorbers, reactive diluents, thixotropic agents, fillers, plasticizers, and mixtures thereof.

[0041] A second object of the present invention is the use of the above-described moisture-curing composition as a sealant, as an adhesive for bonding two substrates together, or as a coating on the surface of a substrate.

[0042] Another object of the present invention is to provide an article comprising at least one layer obtained by curing the above-mentioned moisture-curable composition.

[0043] The present invention is able to meet the above needs. In particular, the present invention provides moisture curable compositions that can provide good flame retardant properties without compromising the cure speed and mechanical properties of the cured composition.

[0044] This is achieved by combining at least one organofunctional silane compound having at least one amino group and a hydrolyzable silyl group and at least one flame retardant component comprising a halogen-free nitrogen-phosphorus flame retardant in the moisture-curable composition. More specifically, such a combination makes it possible to overcome the above-mentioned slow curing problem conventionally encountered in moisture-curable compositions comprising at least one silyl-modified polymer and a flame retardant.

[0045] In addition, since the at least one flame retardant component comprises a halogen-free nitrogen-phosphorus flame retardant, it has low toxicity, low smoke emission, and provides excellent properties with respect to high thermal stability and low loading. Thus, the present invention provides a moisture-curable composition that is beneficial to environmental and health issues and provides good flame retardancy and mechanical properties. DETAILED DESCRIPTION

[0046] The invention will now be described in more detail in the following description without being limited thereto.

[0047] Component (A)

[0048] The moisture-curing composition according to the invention comprises at least one silyl-modified polymer (A).

[0049] "Silyl-modified polymer" or "SMP" means in the present application (unless otherwise stated): a polymer which has been modified with reactive silyl groups, preferably at the end (=terminus) of the main chain or at the end of any side branches. In other words, reactive silyl groups have been attached to the polymer chains. These SMPs are crosslinked with each other via hydrolysis and condensation reactions to form a three-dimensional elastic polymer network. The term "silylated polymer" is also used in this context and has a similar meaning. This means that silyl groups have been attached to the polymer.

[0050] "Reactive silyl group" means in this application (unless otherwise specified): a silicon-containing chemical group that can hydrolyze in the presence of moisture to form a siloxane bond. In other words: a water-reactive group containing a silicon atom that can form a siloxane bond with another reactive silyl group. Other terms used and having approximately the same meaning are: "silyl-containing functional group" or "silicon-containing functional group" or "reactive silicon group.

[0051] According to an embodiment, the silyl-modified polymer (A) comprises at least one, preferably at least two, groups of the following formula (I):

[0052] -Si(R 4 ) p (OR 5 ) 3-p (I)

[0053] in:

[0054] -R 4 represents a linear or branched alkyl radical containing 1 to 4 carbon atoms, it being possible that, when several radicals R are present 4 When , these groups are the same or different;

[0055] -R 5 represents a linear or branched alkyl radical containing 1 to 4 carbon atoms, it being possible that, when several radicals R are present 5 When these groups are identical or different, the possibility is that the two groups OR 5 Can be joined in the same loop;

[0056] - p is an integer equal to 0, 1 or 2, preferably equal to 0 or 1.

[0057] The silyl-modified polymer (A) as defined above comprises at least one crosslinkable alkoxysilane group. The crosslinkable alkoxysilane group is preferably at the terminal position of the polymer. However, positions in the middle of the chain are not excluded. Before applying the moisture-curable composition, the silyl-modified polymer is not crosslinked. The moisture-curable composition is applied under conditions that enable it to be crosslinked.

[0058] The silyl-modified polymer (A) is generally in the form of a more or less viscous liquid. Preferably, the silyl-modified polymer has a viscosity in the range of 10 to 200 Pa·s, preferably in the range of 20 to 175 Pa·s, measured, for example, according to a Brookfield-type method at 23° C. and 50% relative humidity (S28 needle).

[0059] The silyl-modified polymers (A) preferably contain two groups of the formula (I), but may also contain three to six groups of the formula (I).

[0060] Preferably, the silyl-modified polymer (A) has a number average molar mass (Mn) in the range of 500 to 50000 g / mol, more preferably in the range of 700 to 20000 g / mol. The number average molar mass (Mn) of the polymer can be measured by methods well known to those skilled in the art, for example by NMR and size exclusion chromatography using polystyrene standards.

[0061] According to an embodiment, the silyl-modified polymer (A) corresponds to one of the formulae (II), (III) or (IV):

[0062]

[0063] in:

[0064] R 4 , R 5 and p have the same meanings as in the above formula (I),

[0065] P represents a saturated or unsaturated linear or branched polymeric group, which optionally contains one or more heteroatoms such as oxygen, nitrogen, sulfur or silicon, and preferably has a number average molar mass (Mn) ranging from 100 g / mol to 48600 g / mol, more particularly from 300 g / mol to 18600 g / mol, or from 500 g / mol to 12600 g / mol,

[0066] R 1 denotes a divalent hydrocarbon-based radical containing 5 to 15 carbon atoms, which may be aromatic or aliphatic, linear, branched or cyclic,

[0067] R 3 represents a linear or branched divalent alkylene group containing 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms,

[0068] X represents a group consisting of -NH-, -NR 6 -, or a divalent group of -S-,

[0069] R 6denotes a linear or branched alkyl group containing 1 to 20 carbon atoms and which may also contain one or more heteroatoms,

[0070] f is an integer ranging from 1 to 6, preferably ranging from 2 to 5, preferably 2 to 4, more preferably 2 to 3.

[0071] Preferably, in the above formula (II), (III) and / or (IV), P represents a polymer group which is selected in a non-limiting manner from polyethers, polycarbonates, polyesters, polyolefins, polyacrylates, polyether polyurethanes, polyester polyurethanes, polyolefin polyurethanes, polyacrylate polyurethanes, polycarbonate polyurethanes and segmented polyether / polyester polyurethanes.

[0072] For example, EP 2468783 describes silyl-modified polymers of the formula (II) in which P represents a polymer group containing a polyurethane / polyester / polyether block.

[0073] According to an embodiment, the silyl-modified polymer (A) is selected from silyl-modified polyethers, silyl-modified polyurethanes, and mixtures thereof.

[0074] According to a particular embodiment, the silyl-modified polymer (A) corresponds to one of the formulae (II′), (III′) or (IV′):

[0075]

[0076] In the formula (II'), (III') or (IV'):

[0077] R 1 , R 3 , R 4 , R 5 ,X,R 6 and p have the same meanings as in the above formulae (II), (III) and (IV),

[0078] R 2 represents a saturated or unsaturated linear or branched divalent hydrocarbon-based group, which optionally contains one or more heteroatoms such as oxygen, nitrogen, sulfur or silicon, and preferably has a number average molar mass (Mn) ranging from 100 g / mol to 48600 g / mol, more particularly from 300 g / mol to 18600 g / mol, or from 500 g / mol to 12600 g / mol,

[0079] n is an integer greater than or equal to 0.

[0080] In the silyl-modified polymers of the formula (II′), (III′) or (IV′) defined above, when the radical R 2When one or more heteroatoms are included, the heteroatoms are not present at the ends of the chain. In other words, the divalent group R bonded to the oxygen atom adjacent to the silyl-modified polymer 2 The free valences of each originate from a carbon atom. 2 The main chain of is terminated at each of the two ends with a carbon atom which then has a free valence.

[0081] According to an embodiment, the silyl-modified polymer (A) is obtained from a polyol selected from polyether polyols, polyester polyols, polycarbonate polyols, polyacrylate polyols, polysiloxane polyols, and polyolefin polyols, and mixtures thereof, and more preferably from a diol selected from polyether diols, polyester diols, polycarbonate diols, polyacrylate diols, polysiloxane diols, polyolefin diols, and mixtures thereof. In the case of the polymers of formula (II'), (III') or (IV') described above, such a diol may be selected from the formula HO-R 2 -OH means, where R 2 has the same meaning as in formula (II'), (III') or (IV').

[0082] For example, in R which may be present in formula (II'), (III') or (IV') 2 Among the divalent groups, the following divalent groups may be mentioned, the formula below of which shows two free valencies:

[0083] Derivatives of polypropylene glycol:

[0084]

[0085] Derivatives of polyester diols:

[0086]

[0087] Derivatives of polybutadiene glycol:

[0088]

[0089] Derivatives of polyacrylate diols:

[0090]

[0091] Derivatives of polysiloxanediol:

[0092]

[0093] in:

[0094] q represents the group R 2The number average molecular weight ranges from 100 g / mol to 48 600 g / mol, preferably from 300 g / mol to 18 600 g / mol, more preferably from 500 g / mol to 12 600 g / mol,

[0095] r and s represent zero or such that the group R 2 The number average molecular weight range is a non-zero integer from 100 g / mol to 48 600 g / mol, preferably from 300 g / mol to 18 600 g / mol, more preferably from 500 g / mol to 12 600 g / mol, it should be understood that the sum of r+s is not zero,

[0096] Q 1 represents a linear or branched, saturated or unsaturated, aromatic or aliphatic divalent alkylene radical preferably containing 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms,

[0097] Q 2 represents a linear or branched divalent alkylene group preferably containing 2 to 36 carbon atoms, more preferably 1 to 8 carbon atoms,

[0098] Q 3 , Q 4 , Q 5 , Q 6 , Q 7 and Q 8 Independently of one another represent a hydrogen atom or an alkyl, alkenyl or aromatic group preferably containing 1 to 12 carbon atoms, preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms.

[0099] According to one embodiment, R 1 One of the following divalent groups, the formula of which shows two free valencies:

[0100] a) Divalent groups derived from isophorone diisocyanate (IPDI):

[0101]

[0102] b) Divalent radicals derived from dicyclohexylmethane diisocyanate (H12MDI):

[0103]

[0104] c) Divalent groups derived from toluene diisocyanate (TDI):

[0105]

[0106] d) Divalent radicals derived from the 4,4' and 2,4' isomers of diphenylmethane diisocyanate (MDI):

[0107]

[0108] e) Divalent groups derived from hexamethylene diisocyanate (HDI):

[0109] -(CH2)6-

[0110] f) Divalent groups derived from meta-xylylene diisocyanate (m-XDI):

[0111]

[0112] The polymers of formula (II) or (II′) can be obtained according to the processes described in EP 2336208 and WO 2009 / 106699. A person skilled in the art will know how to adjust the manufacturing processes described in these two documents when using different types of polyols. Among the polymers corresponding to formula (II), mention may be made of:

[0113] STP-E10 (available from WACKER): contains two dimethoxy-type groups (I) (n equals 0, p equals 1, and R 4 and R 5 represents a methyl group) and having a number average molar mass (Mn) of 8 889 g / mol, wherein R 3 represents a methylene group;

[0114] STP-E30 (available from WACKER): contains two dimethoxy-type groups (I) (n equals 0, p equals 1, and R 4 and R 5 represents a methyl group) and having a number average molar mass (Mn) of 14 493 g / mol, wherein R 3 represents a methylene group;

[0115] 1050MM (available from MOMENTIVE): contains two trimethoxy-type groups (I) (n is not 0, p is 0, and R 5 represents a methyl group) and having a number average molar mass (Mn) of 16393 gg / mol, wherein R 3 Represents n-propyl:

[0116] Y-19116 (available from MOMENTIVE): contains two trimethoxy-type groups (I) (n is not 0, and R 5represents a methyl group) and having a number average molar mass (Mn) of 15 000 to 17 000 g / mol, wherein R 3 represents n-propyl;

[0117] S XP 2636 (available from BAYER): contains two trimethoxy-type groups (I) (n is not 0, p is equal to 0, and R 5 represents a methyl group) and having a number average molar mass (Mn) of 15 038 g / mol, wherein R 3 represents n-propylene;

[0118] 1012LM (available from MOMENTIVE): corresponds to a group (I) containing two trimethoxy groups (n is not 0, p is equal to 0, and R 5 represents a methyl) polyurethane;

[0119] The polymers of formula (III) or (III') can be obtained by hydrosilylation of polyether diallyl ethers according to the process described, for example, in EP 1829928. Among the polymers corresponding to formula (III), mention may be made of:

[0120] Polymer MS 350 (available from KANEKA): corresponds to a group (I) containing two dimethoxy groups (p is equal to 1, and R 4 and R 5 denotes a methyl group) and having a number average molar mass (Mn) in the range of 14 000 to 16 000 g / mol;

[0121] Polymer MS 260 (available from KANEKA): corresponds to a group (I) containing two dimethoxy groups (p equals 1, R 4 and R 5 denotes a methyl group) and having a number average molar mass (Mn) of 16 000 to 18 000 g / mol, wherein R 3 represents ethyl;

[0122] Polymer MS S303H (available from KANEKA): corresponds to two dimethoxy-type containing groups (I) (p equals 1, and R 4 represents a methyl group) and having a number average molecular weight (Mn) of about 22 000 Daltons.

[0123] polymer 725 (available from KANEKA): corresponds to a group (I) containing two dimethoxy groups (p is equal to 1, and R 4represents a polyether of methyl).

[0124] The polymers of formula (IV) or (IV') can be obtained, for example, by reaction of a polyol with one or more diisocyanates followed by reaction with an aminosilane or mercaptosilane. The process for preparing polymers of formula (IV) or (IV') is described in EP 2583988. A person skilled in the art will know how to adapt the manufacturing process described in said document when using different types of polyols.

[0125] According to a preferred embodiment, the moisture-curing composition according to the invention comprises at least one silyl-modified polymer of the formula (II) and / or (II′) or at least one silyl-modified polymer of the formula (III) and / or (III′).

[0126] According to a particularly preferred embodiment, the moisture-curing composition according to the invention comprises at least one silyl-modified polymer of the formula (III′), in particular in which R 2 The crosslinking time of the adhesive composition is then advantageously completely reduced by divalent radicals derived from polyethers, preferably from poly(oxyalkylene) glycols and even more particularly from polypropylene glycols.

[0127] The amount of the silyl-modified polymer (A) in the moisture-curable composition may depend on the use of the moisture-curable composition. Specifically, for use as a sealant, the moisture-curable composition will preferably contain 5% to 50% by mass of the silyl-modified polymer, preferably 10% to 40% by mass of the silyl-modified polymer, relative to the total amount of the moisture-curable composition. For adhesives for formulating pressure-sensitive self-adhesive articles (PSA type), the moisture-curable composition will preferably contain 10% to 99.9% by mass, preferably 15% to 90% by mass, more preferably 20% to 80% by mass of the silyl-modified polymer, relative to the total amount of the moisture-curable composition.

[0128] Component (B )

[0129] The moisture-curable composition according to the present invention comprises at least one organofunctional silane compound (B) having at least one amino group and a hydrolyzable silyl group.

[0130] In the present application, "amino" refers to a nitrogen-containing group or organic structure in which the nitrogen atom is connected to hydrogen or carbon via a single bond. "Amino" may be a primary amino group, a secondary amino group or a tertiary amino group.

[0131] According to an embodiment, the organofunctional silane compound (B) has two or more, preferably three, amino groups. In some embodiments, the organofunctional silane compound (B) may be linear or branched.

[0132] "Hydrolyzable silyl" means a group comprising one or more hydrolyzable functional groups. According to an embodiment, the hydrolyzable silyl group may have the formula -SiXYZ, wherein X, Y and Z are independently selected from hydrogen, C1-C8 alkyl, C1-C8 alkoxy. At least one of the substituents X, Y, Z is a hydrolyzable group. Preferably, at least two or all three of the substituents X, Y, Z are hydrolyzable groups. Preferably, the hydrolyzable group for at least one of the substituents X, Y, Z is a C1 to C8 alkoxy, more preferably a trialkoxy. Preferably, the alkoxy is a methoxy or ethoxy, and thus the hydrolyzable group is preferably a trimethoxy or triethoxy.

[0133] According to an embodiment, the organofunctional silane compound (B) has the formula XYZSi-A-NH-(B-NH) z -H, z is an integer from 0 to 4, and A and B are alkyl divalent groups. Each alkyl divalent group is preferably linear. Each alkyl divalent group preferably contains 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 2 or 3 carbon atoms. For example, A may be C3H6 and / or B may be C2H4.

[0134] According to an embodiment, the organofunctional silane compound (B) comprises an aminoalkylalkoxysilane selected from the group consisting of:

[0135] 3-(Trimethoxysilyl)propylamine (AMMO) having the formula:

[0136]

[0137] [3-(2-aminoethylamino)propyl]trimethoxysilane (DAMO) having the formula:

[0138] and

[0139] 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane (TRIAMO) having the formula:

[0140]

[0141] According to an embodiment, the organofunctional silane compound (B) includes two or more selected from AMMO, DAMO, and TRIAMO.

[0142] Preferably, the organofunctional silane compound (B) comprises TRIAMO.

[0143] Component (C)

[0144] The moisture-curable composition of the present invention comprises at least one flame retardant component (C) comprising a halogen-free nitrogen-phosphorus flame retardant.

[0145] For the purposes of the present invention, "halogen-free nitrogen-phosphorus flame retardant" means a flame retardant that does not contain halogens (fluorine, chlorine, bromine, iodine, astatine) and contains the elements nitrogen and phosphorus.

[0146] For the purposes of this invention, "flame retardant" means a substance or combination of substances applied to or included in a material to prevent the occurrence of fire or slow the development of fire. A variety of different chemical substances based on different properties and / or molecular structures of the substance can function as a flame retardant. Basically, the flame retardant effect (effect) can be achieved by eliminating or reducing one or more factors in the fuel, heat and oxygen cycle to break the cycle in the combustion process.

[0147] The flame retardant mechanism may be physical and / or chemical. For example, the flame retardant effect may be based on an endothermic effect and / or a covering effect and / or a suffocation effect. In the endothermic effect, the flame retardant material absorbs a portion of the heat released by the burning material to reduce the surface temperature of the burning material, thereby reducing the generation of smoke and preventing the spread of fire. In the covering effect, the flame retardant material forms a stable foam layer covering the surface of the combustible material when burning, and the stable foam layer isolates the surface of the combustible material from the air and prevents the escape of combustion gases, thereby preventing the further development of the fire. In the suffocation effect, the flame retardant material decomposes at high temperatures and releases non-combustible gases, so that the concentration of the combustible gas decreases with the increase of the volume of the non-combustible gas, thereby preventing a continuous combustion process.

[0148] The halogen-free nitrogen-phosphorus flame retardant is preferably an intumescent flame retardant, which produces a carbon-based foam layer when subjected to heating above a certain threshold. The intumescent carbonized layer has the functions of heat insulation, oxygen isolation and smoke suppression, thereby blocking the combustion process. Intumescent flame retardants are environmentally friendly because they do not produce toxic fumes or corrosive gases when burned, and do not require antimony trioxide synergists that are conventionally used with halogenated flame retardants. It has been found that the combination of phosphorus and nitrogen in the flame retardant has a synergistic effect during the combustion process, which can improve the flame retardant effect.

[0149] Preferably, the intumescent flame retardant comprises three parts: an acid source, a carbon source (referred to as a "carbonific") and a gas source (referred to as a "spumific"). The same compound may be used as more than one of the acid source, carbon source and gas source, possibly as all three. Alternatively, the acid source, carbon source and gas source may be provided by a combination of different compounds.

[0150] The acid source plays a major role in flame retardancy, and the charring agent and the foaming agent are synergists. The acid source is generally an inorganic acid, or a compound that can form an inorganic acid after heating to a certain temperature, such as phosphoric acid, phosphorus oxychloride, and ammonium polyphosphate (APP). The charring agent acts as a dehydrating agent or carbonization accelerator for forming a carbonized layer of the foam, and may include polyhydroxy compounds preferably having a high carbon content, such as pentaerythritol, starch, and triazine derivatives. The foaming agent may include, for example, melamine, dicyandiamide, piperazine, and ethylenediamine.

[0151] According to an embodiment, the halogen-free nitrogen-phosphorus flame retardant comprises one or more selected from piperazine polyphosphate (PAPP), piperazine phosphate, melamine polyphosphate (MPP), melamine cyanurate (MCA) and ammonium polyphosphate (APP). Preferably, the halogen-free nitrogen-phosphorus flame retardant comprises PAPP.

[0152] In this patent application, "polyphosphate" is a chemical structure formed by tetrahedral PO4 structural units linked together by shared oxygen atoms. Polyphosphates can adopt linear or cyclic ring structures. The repeating unit of polyphosphates can be two or more. PAPP represents a group of compounds with different polyphosphate repeating units.

[0153] PAPP can be prepared by the reaction between piperazine and polyphosphoric acid or polyphosphate (e.g. pyrophosphoric acid). If the flame retardant effect can be achieved, there is no particular limitation on the mixing ratio of piperazine to polyphosphoric acid. PAPP can also be obtained by heating and condensing piperazine orthophosphate. PAPP can be prepared as disclosed herein, or purchased directly from the market, as there are commercially available PAPP products.

[0154] PAPP contains a piperazine moiety and a polyphosphate moiety. When there are two repeating units of the PO4 structure in PAPP, it is a piperazine pyrophosphate represented by the following formula:

[0155]

[0156] From the viewpoint of flame retardancy, easy handling and storage stability, it is preferred to use piperazine pyrophosphate in the flame retardant component (C) of the moisture-curable composition according to the present invention. In the case where piperazine pyrophosphate is used as component (C) in a mixture, it is preferred that the mass content of piperazine pyrophosphate is the highest in the mixture.

[0157] PAPP combines acid source, carbon source and gas source. It has excellent charring and flame retardant properties.

[0158] Halogen-free nitrogen-phosphorus flame retardants, such as PAPP, MCA and MPP, have been widely used in thermoplastic materials such as polypropylene (PP), polyethylene (PE), acrylonitrile-butadiene-styrene (ABS), epoxy resin (EP). However, the use of halogen-free nitrogen-phosphorus flame retardants in moisture-curable compositions for adhesives or coatings has not been reported.

[0159] Ammonium polyphosphate (APP) is another halogen-free intumescent flame retardant acid source. PAPP-based flame retardants provide better flame retardancy and higher thermal stability than APP-based flame retardants.

[0160] According to an embodiment, the flame retardant component (C) comprises 25 to 100 mass % of PAPP and 0 to 75 mass % of at least one flame retardant other than PAPP, preferably 50 to 100 mass % of PAPP and 0 to 50 mass % of at least one flame retardant other than PAPP, more preferably 75 to 100 mass % of PAPP and 0 to 25 mass % of at least one flame retardant other than PAPP, based on the total weight of the flame retardant component (C).

[0161] According to an embodiment, at least one flame retardant other than PAPP is any compound other than PAPP having flame retardant function, such as nitrogen phosphorus flame retardant, nitrogen flame retardant, phosphorus flame retardant, metal oxide flame retardant, metal hydroxide flame retardant, or a combination thereof. Examples of metal oxide flame retardants include ZnO.

[0162] Curing catalyst (D)

[0163] According to an embodiment, the moisture-curable composition according to the present invention may further include a curing catalyst (D).

[0164] The catalyst (D) may be any curing or crosslinking catalyst known to those skilled in the art for catalyzing the condensation of silanols. For example, the catalyst (D) may comprise an amine or an organometallic derivative, and in particular an organic derivative of iron, titanium, aluminum, or divalent or tetravalent tin.

[0165] Examples of such catalysts include:

[0166] - aminosilanes, such as N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (available from MOMENTIVE under the name A-1120 commercially available) or 3-aminopropyltrimethoxysilane,

[0167] - organic derivatives of titanium, such as titanium acetylacetonate (available from Dorf Ketal under the name AA75 is commercially available),

[0168] - Aluminium, such as aluminium chelates (available from KING INDUSTRIES under the name 5218 commercially available),

[0169] - amines, such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), diethyl ether-2,2′-morpholine (DMDEE), 1,4-diazabicyclo[2.2.2]octane (DABCO),

[0170] - Catalysts with tin, such as 216 (available from TIB CHEMICALS),

[0171] -Dioctyltin based catalysts such as 223 (available from Evonik),

[0172] - Catalysts based on titanium ethylacetoacetate complexes, such as 726 (available from Dorf Ketal),

[0173] - Catalysts based on the reaction product of tetraethyl silicate (H4SiO4) and bis(acetoxy)dioctylstannane (CAS No. 93925-43-0), such as S-1 (available from NITTO KASEI).

[0174] Composition

[0175] According to an embodiment, the moisture-curable composition according to the present invention comprises:

[0176] - 30 to 60 parts by mass of a silyl-modified polymer (A);

[0177] - 0.2 to 3 parts by mass of an organofunctional silane compound (B); and

[0178] - 20 to 50 parts by mass of a flame retardant component (C).

[0179] Preferably, the moisture-curable composition may further include 0.01 to 1 parts by mass of a curing catalyst (D).

[0180] Other additives

[0181] The moisture-curable composition according to the present invention may further comprise at least one additive selected from the group consisting of solvents, pigments, dyes, adhesion promoters, desiccants, molecular sieves, antioxidants, wetting agents, UV absorbers, reactive diluents, thixotropic agents, fillers, plasticizers, and mixtures thereof.

[0182] The total content of other additives may range from 0 to 50% by mass, preferably from 0 to 25% by mass, and more preferably from 0 to 10% by mass, relative to the total amount of the moisture-curable composition.

[0183] use

[0184] The invention also relates to the use of the above-described moisture-curing composition as a sealant (seal, caulking agent), as an adhesive for bonding two substrates together, or as a coating on the surface of a substrate.

[0185] According to an embodiment, the moisture-curing composition according to the invention is used as a sealant, adhesive or coating for equipment in the transport or construction industry, in particular for trains or cars.

[0186] The moisture-curable composition according to the present invention may be coated or applied using various application techniques known in the art, including contact-type application (such as slot die coating) and non-contact-type application (such as spraying or fiberizing).

[0187] The moisture-curable composition according to the invention can be applied to a surface, for example at a temperature in the range of 5 to 50° C. The composition can be cured (crosslinked) under these conditions. In order to bond two substrates, such a coated surface can be brought into contact with the surface of another substrate so as to form an adhesive joint bonding the two substrates. The substrates can be of different or identical nature and have various forms (layers, or films, threads, fleece).

[0188] For example, the surface to be bonded or coated can include nonwovens, tissues, rubber, paper, wood, composite materials, can be elastic or inelastic plastics, metals or metal alloys, concrete, mortar, bricks, tiles, natural stone, glass, glass-ceramics, and any mixture thereof. Preferably, the surface is a metal or metal alloy surface such as aluminum, or a plastic surface such as polyurethane, polyolefin, polypropylene (PP), polyethylene (PE) and polyethylene terephthalate (PET). In order to be used as an adhesive for bonding two substrates together, each substrate can be selected independently of each other in the above-mentioned materials.

[0189] Products

[0190] The invention also relates to an article comprising at least one layer obtained by curing a moisture-curing composition according to the invention. The curing of the moisture-curing composition is promoted by moisture, for example by atmospheric moisture. Such an article can be assembled as part of a train or automotive equipment.

[0191] Example

[0192] The following examples illustrate the invention without limiting it.

[0193] The compositions of Examples 1 to 8 prepared according to Table 1 were applied as a layer with a thickness of 2 mm on The samples were then cut into Type I dumbbells according to ISO 37 and clamped on a universal testing machine (UTM) available from Instron for dumbbell tensile strength testing. The modulus was read from the tensile test stress-strain curve as the chord slope at 5%-10% strain. The results are shown in Table 1.

[0194] Table 1

[0195]

[0196]

[0197] The modulus reflects the stiffness of the material itself. A higher modulus means a higher crosslink density of the polymer matrix. In these examples, the modulus was used to monitor the crosslink density of the prepared composition.

[0198] The oxygen index (OI), also known as the limiting oxygen index (LOI) or critical oxygen index (COI), is a parameter that describes the tendency of a material to sustain a flame and is commonly used to characterize the flammability of a material. The oxygen index is defined as: OI = O2 / (O2+N2), where O2 and N2 are the minimum oxygen and nitrogen concentrations in the inflow gas required to pass the minimum burning length standard. The unit of the oxygen index is percentage, %.

[0199] Since air contains about 20.95% oxygen by volume, any material with an oxygen index of less than 20.95% will burn easily in air. In contrast, the burning behavior and flame propagation tendency of materials with a limiting oxygen index greater than 20.95% will be reduced or even zero after the ignition source is removed. Higher OI values ​​represent better flame retardancy. OI values ​​can be measured according to any test method (including specimen preparation and measurement) specified in standards such as ASTM D2863, ISO 4589-2, and NES 714.

[0200] As can be seen from Table 1 above, all the Examples were found to provide sufficiently high OI exceeding 29%.

[0201] As for modulus, Examples 1-6 show that the combination of the silyl-modified polymer (A), the organofunctional silane compound (B), and the flame retardant component (C) overcomes the problem of slow curing and maintains the mechanical properties of the composition.

[0202] Example 8 specifically shows that TRIAMO effectively improves the stiffness of the composition compared to Example 7 using AMMO.

Claims

1. A moisture curable composition comprising: - at least one silyl-modified polymer (A); - at least one organofunctional silane compound (B) having at least one amino group and a hydrolyzable silyl group; and - at least one flame retardant component (C) comprising a halogen-free nitrogen-phosphorus flame retardant.

2. The moisture-curable composition according to claim 1, comprising - 30 to 60 parts by mass of the silyl-modified polymer (A); - 0.2 to 3 parts by mass of the organofunctional silane compound (B); and - 20 to 50 parts by mass of the flame retardant component (C).

3. The moisture-curable composition according to claim 1 or 2, wherein the halogen-free nitrogen-phosphorus flame retardant comprises one or more selected from piperazine polyphosphate (PAPP), piperazine phosphate, melamine polyphosphate (MPP), melamine cyanurate (MCA) and ammonium polyphosphate (APP), preferably, the halogen-free nitrogen-phosphorus flame retardant comprises PAPP.

4. The moisture-curable composition according to any one of claims 1 to 3, wherein the flame retardant component (C) comprises 25 to 100 mass % of piperazine polyphosphate (PAPP) and 0 to 75 mass % of at least one flame retardant other than PAPP, based on the total weight of the flame retardant component (C).

5. The moisture-curable composition of claim 4, wherein the at least one flame retardant other than PAPP is a nitrogen phosphorus flame retardant, a nitrogen flame retardant, a phosphorus flame retardant, a metal oxide flame retardant, a metal hydroxide flame retardant, or a combination thereof.

6. The moisture-curable composition according to any one of claims 1 to 5, wherein the PAPP comprises piperazine pyrophosphate. 7 . The moisture-curable composition according to claim 1 , wherein the organofunctional silane compound (B) has two or more amino groups.

8. The moisture curable composition according to any one of claims 1 to 7, wherein the hydrolyzable silyl group of the organofunctional silane compound (B) has the formula -SiXYZ, wherein X, Y and Z are independently selected from hydrogen, C1-C8 alkyl and C1-C8 alkoxy, and at least one of X, Y or Z is a hydrolyzable group.

9. The moisture-curable composition according to claim 8, wherein the hydrolyzable group for at least one of X, Y and Z is a C1-C8 alkoxy group.

10. The moisture curable composition according to claim 8 or 9, wherein the organofunctional silane compound (B) has the formula XYZSi-A-NH-(B-NH) z -H, z is an integer from 0 to 4, and A and B are divalent alkyl groups.

11. The moisture-curable composition according to claim 10, wherein the organofunctional silane compound (B) comprises an aminoalkylalkoxysilane selected from the group consisting of: 3-(Trimethoxysilyl)propylamine having the formula: [3-(2-aminoethylamino)propyl]trimethoxysilane having the formula: and 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane having the formula: 12 . The moisture-curable composition according to claim 1 , wherein the silyl-modified polymer (A) comprises one or more selected from the group consisting of a silyl-modified polyether and a silyl-modified polyurethane. 13 . The moisture-curable composition according to claim 1 , further comprising a curing catalyst (D).

14. Use of the moisture-curing composition according to any one of claims 1 to 13 as a sealant, as an adhesive for bonding two substrates together, or as a coating on the surface of a substrate.

15. Article comprising at least one layer obtained by curing the moisture-curable composition according to any one of claims 1 to 13.

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