Compositions comprising moisture-crosslinkable polymers

Abstract

The invention relates to a composition comprising:-a moisture-crosslinkable polymer,-at least 1% by weight of unexpanded thermally expandable organic particles, and-at least 20% by weight of an inorganic filler, the weight percentages being relative to the total weight of the composition. The invention also relates to a method for bonding substrates implementing a composition according to the invention. Furthermore, the invention relates to an article comprising a composition according to the invention. The invention also relates to a method for separating a substrate implementing a composition according to the invention and comprising a heating step. Finally, the invention relates to the use of the composition according to the invention.

Description

Technical Field

[0001] The present invention relates to a composition comprising a polymer crosslinkable by moisture, its use, a method for bonding substrates, an article, and a method for separating substrates. Background Art

[0002] A battery housing, especially for a motor vehicle, generally comprises a cover and a container sealed together, with a battery module or a unit cell located inside the battery housing.

[0003] There are several ways to seal the battery cover and the battery container of a battery housing.

[0004] Traditionally, one way is to use a "gasket", which is a shaped rubber part usually made of EPDM rubber (ethylene propylene diene monomer rubber), silicone rubber, or polyurethane rubber. The gasket is arranged between the cover and the container, and the sealing is achieved by spacer bolts or riveting. To a certain extent, the tightened bolts or riveting ensure the sealing effect of this structure is airtight or waterproof by compressing the gasket. Then the gasket contacts both the cover and the container, but there is no chemical adhesion or bonding between them.

[0005] A similar typical way is to use a "form-in-place gasket" for sealing. Different from the above traditional gasket, an adhesive is applied to the cover or the container, and it forms a foam or non-foam sealing gasket that adheres well to the component to which it is applied. However, there is still no chemical adhesion or bonding with other components.

[0006] Sealing with a gasket has the advantage that the cover can be very easily opened after removing the bolts. However, such a gasket cannot provide excellent sealing for the battery housing, especially when the dimensional tolerances of the cover or the container are large (especially when the cover or the container is made of a non-metallic composite material such as Sheet Moulding Composite), or when using or testing under harsh working conditions or aging requirements. When using a gasket, there is still a possibility of leakage from time to time.

[0007] Another typical way is the "bonding" method: between the cover and the container, a sealant is used instead of a gasket. The sealant is applied to the cover or the container in an uncured state, and then the two components are brought into contact during the open time of the sealant. After curing, the sealant is solid and adheres completely to both the cover and the container, with chemical bonding. This bonding method provides very good sealing properties to achieve excellent water / air resistance, and due to the chemical bonding between the cover and the container, the bonding strength is also good even under certain long-term aging or vibration conditions or after them. To enhance the sealing effect, bolts or other kinds of riveting can also be adopted.

[0008] The disadvantage of this bonding method is that due to the elastic chemical properties of the sealant (in particular, the friction between the blade and the elastic sealant and the heat generated during cutting increase the inconvenience of opening), it is difficult to disassemble the lid and the container even by mechanical cutting or drilling. In addition, since these sealants also have good bonding strength to support harsh aging conditions, the disassembly of the lid and the container easily causes one or both of them to deform or break.

[0009] Therefore, it is not possible to easily disassemble the battery for maintenance or repair operations, and it is even less possible to manually disassemble the battery.

[0010] Therefore, a new solution is needed, which enables the provision of an article, in particular a battery housing, which is effectively sealed and can be easily disassembled when necessary (for example, for repair or maintenance operations), in particular manually. SUMMARY OF THE INVENTION

[0011] The present invention relates to a composition comprising:

[0012] - a moisture-crosslinkable polymer,

[0013] - at least 1 wt% of unexpanded thermally expandable organic particles, and

[0014] - at least 20 wt% of an inorganic filler,

[0015] The weight percentages are relative to the total weight of the composition.

[0016] The present invention also relates to a method for bonding substrates, comprising the steps of:

[0017] - coating the composition according to the present invention on at least one surface of the substrate, and then

[0018] - bringing the substrates into contact.

[0019] Furthermore, the present invention relates to an article comprising the composition according to the present invention, the composition bonding at least two substrates of the article.

[0020] The present invention also relates to a method for separating substrates which implements the composition according to the present invention and includes a heating step.

[0021] Finally, the present invention relates to the use of the composition according to the present invention as an adhesive or a sealant, or for the manufacture of an article comprising thermally separable substrates.

[0022] The present invention makes it possible to solve the above needs. In particular, the composition according to the present invention surprisingly makes it possible to provide an effective sealing structure (in particular a battery housing, where the composition is applied between the lid and the container), which can be easily disassembled if necessary. Detailed Description

[0023] Composition according to the invention

[0024] The present invention relates to a composition comprising:

[0025] - a moisture-crosslinkable polymer,

[0026] - at least 1% by weight of unexpanded thermally expandable organic particles, and

[0027] - at least 20% by weight of an inorganic filler,

[0028] The percentages by weight are relative to the total weight of the composition.

[0029] Wettable Gas Crosslinked polymer

[0030] The composition according to the present invention comprises a moisture-crosslinkable polymer.

[0031] In the presence of water (such as from air Wet gas), individual polymer molecules can crosslink with each other (polymer molecules can bond to another polymer molecule) to form a crosslinked polymer network.

[0032] The moisture-crosslinkable polymer can be selected from polyurethanes having -NCO end groups, silylated polymers and mixtures thereof, preferably selected from silylated polymers and mixtures thereof.

[0033] The polyurethane having -NCO end groups can be prepared in a well-known manner by reacting:

[0034] - a polyisocyanate compound, with

[0035] - at least one polyol.

[0036] The polyisocyanate compound may be selected from isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane 4,4'-diisocyanate (H12MDI), toluene diisocyanate (TDI), 1,4-cyclohexylene diisocyanate, 1,2-cyclohexylene diisocyanate, 2,4-diisocyanato-1-methylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, m-xylene diisocyanate (m-XDI), hydrogenated m-xylene diisocyanate (m-H6XDI), tetramethylxylene diisocyanate (TMXDI), 1,2-ethylene diisocyanate, 1,3-propylene diisocyanate, 1,4-butylene diisocyanate, 1,5-pentamethylene diisocyanate (PDI), 1,6-hexamethylene diisocyanate (HDI) and mixtures thereof, preferably selected from IPDI, MDI, TDI, m-XDI, HDI and mixtures thereof.

[0037] The polyol, preferably diol, may be selected from polyether polyols, polyester polyols, polycarbonate polyols, polyacrylate polyols, polysiloxane polyols, polyolefin polyols and mixtures thereof, preferably selected from polyether polyols.

[0038] In the presence of moisture, some -NCO groups of the polyurethane molecules are converted to carbamic acid groups (-NH-C(O)OH), which are unstable and result in amine groups and carbon dioxide (-NH2 + CO2). The formed amine groups react rapidly with the -NCO groups (not yet converted) to form urea bonds (-NH-C(O)NH-): crosslinking occurs and a polymer network is formed.

[0039] "Silylated polymer" means a polymer containing at least one alkoxysilyl group, preferably at least two alkoxysilyl end groups.

[0040] Silylated polymers are usually more or less viscous liquids. Silylated polymers may have a viscosity at 23 °C in the range of 0.5 to 150 Pa·s, preferably 5 to 100 Pa·s, more preferably 5 to 50 Pa·s.

[0041] The viscosity of the silylated polymer can be measured, for example, according to the Brookfield method at 23 °C and 50% relative humidity.

[0042] The silylated polymer preferably contains at least two alkoxysilyl end groups of formula (I):

[0043] -Si(R 4 ) p(( OR 5 ) 3-p

[0044] Wherein:

[0045] -R 4 represents a straight-chain or branched alkyl group having 1 to 4 carbon atoms, and when p is equal to 2, the R 4 groups are the same or different;

[0046] -R 5 represents a straight-chain or branched alkyl group having 1 to 4 carbon atoms, and when p is equal to 0 or 1, the R 5 groups are the same or different, wherein two OR 5 groups may be joined in the same ring;

[0047] -p is an integer equal to 0, 1, or 2.

[0048] Unless otherwise specified, the various groups, moieties, and letters included in the formulas described in this application retain the same definitions throughout this text.

[0049] Preferably, the alkoxysilyl end group has the formula (I), wherein:

[0050] -R 4 represents an alkyl group having 1 or 2 carbon atoms, preferably 1 carbon atom;

[0051] -R 5 represents an alkyl group having 1 or 2 carbon atoms, preferably 1 carbon atom;

[0052] -p is an integer equal to 0 or 1.

[0053] Advantageously, the silylated polymer has the formula (II), (III), or (IV):

[0054]

[0055] wherein:

[0056] -R 4 、R 5 and p have the same meanings as in formula (I) above,

[0057] -P represents a saturated or unsaturated polymeric group having a straight-chain or branched open chain, or containing one or more optionally aromatic rings, optionally containing one or more heteroatoms such as oxygen, nitrogen, sulfur, and / or silicon, preferably oxygen and / or nitrogen,

[0058] -R 1 represents a divalent hydrocarbon group containing 5 to 15 carbon atoms, saturated or unsaturated, straight-chain or branched open chain, or containing one or more optionally aromatic rings,

[0059] -R 3represents a divalent straight-chain or branched alkylene group containing 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms,

[0060] -X represents a divalent group selected from -NH-, -NR 7 -, or -S-,

[0061] -R 7 represents a straight-chain or branched alkyl group containing 1 to 20 carbon atoms and optionally containing one or more heteroatoms,

[0062] -f is an integer ranging from 1 to 6, preferably 2 to 4, more preferably equal to 2 or 3.

[0063] Advantageously, the silylated polymer has the formula (II), (III) or (IV), preferably has the formula (III), wherein P represents a polymer group selected from polyethers, polycarbonates, polyesters, polyolefins, polyacrylates, polyurethanes, polysiloxanes, polyether polyurethanes, polyester polyurethanes, polyolefin polyurethanes, polyacrylate polyurethanes, polycarbonate polyurethanes and polyether / polyester polyurethane block, preferably selected from polyethers, polyurethanes and polyether polyurethanes, more preferably a polymer group selected from polyethers.

[0064] According to an embodiment, the silylated polymer has the formula (II’), (II”), (III’) or (IV’):

[0065]

[0066] (II’)

[0067]

[0068] (II”)

[0069]

[0070] (III’)

[0071]

[0072] (IV’)

[0073] wherein:

[0074] -R 1 、R 3 、R 4 、R 5 、X、R 7 and p have the same meanings as in formulas (II), (III) and (IV),

[0075] -R 2represents a saturated or unsaturated, straight-chain or branched divalent hydrocarbon group which optionally contains one or more heteroatoms, such as oxygen, nitrogen, sulfur, silicon,

[0076] -n is an integer, preferably such that the number-average molecular weight of the silylated polymer varies from 1000 g / mol to 70000 g / mol, preferably from 5000 g / mol to 50000 g / mol, more preferably from 10000 g / mol to 40000 g / mol.

[0077] In the silylated polymers of the above formulae (II’), (II”), (III’) or (IV’), when the group R 2 contains one or more heteroatoms, said heteroatoms are not present at the ends of the chain. In other words, the divalent group R 2 connected to adjacent oxygen atoms of the silylated polymer has free valences each originating from a carbon atom. Thus, the main chain of the R 2 group is capped at each of the two ends by a carbon atom which thus has a free valence.

[0078] When the silylated polymer has the formula (II’) or (IV’), the group R 2 is optionally selected from the following divalent groups, the formula showing two free valences:

[0079] -derived from polypropylene glycol:

[0080]

[0081] -derived from polyester diol:

[0082]

[0083] -derived from polybutadiene diol:

[0084]

[0085] -derived from polyacrylate diol:

[0086]

[0087] -derived from polysiloxane diol:

[0088]

[0089] wherein:

[0090] -q represents an integer, advantageously such that the group R 2The number average molecular weight is in the range of 200 g / mol to 48600 g / mol, preferably 500 g / mol to 18600 g / mol, more preferably 1000 g / mol to 12600 g / mol,

[0091] -r and s represent zero or an integer, advantageously such that the group R 2 has a number average molecular weight in the range from 200 g / mol to 48600 g / mol, preferably from 500 g / mol to 18600 g / mol, more preferably from 1000 g / mol to 12600 g / mol, provided that the sum of r + s is not zero,

[0092] -Q 1 represents a linear or branched, saturated or unsaturated divalent aromatic or aliphatic alkylene group, preferably having 1 to 18 carbon atoms, more preferably 1 to 8 carbon atoms,

[0093] -Q 2 represents a linear or branched divalent alkylene group preferably having 2 to 36 carbon atoms, more preferably 1 to 8 carbon atoms,

[0094] -Q 3 、Q 4 、Q 5 、Q 6 、Q 7 and Q 8 each independently represent a hydrogen atom or an alkyl, alkenyl or aromatic group, preferably having 1 to 12 carbon atoms, preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms.

[0095] According to an embodiment, R 1 is selected from the following divalent groups, the formula showing two free valences:

[0096] a) A divalent group derived from isophorone diisocyanate (IPDI):

[0097]

[0098] b) A divalent group derived from dicyclohexylmethane diisocyanate (H12MDI):

[0099]

[0100] c) Divalent groups derived from the 2,4- and 2,6-isomers of toluene diisocyanate (TDI):

[0101]

[0102] d) Divalent groups derived from 4,4' and 2,4'-isomers of diphenylmethane diisocyanate (MDI):

[0103]

[0104] e) Divalent group derived from hexamethylene diisocyanate (HDI): -(CH2)6-

[0105] f) Divalent groups derived from m-phenylene diisocyanate (m-XDI):

[0106]

[0107] According to a preferred embodiment, the silylated polymer has the formula (II”) or (III’), preferably (III’), and the group R 2 preferably represents a straight-chain or branched divalent alkylene group containing 2 to 4 carbon atoms, more preferably a straight-chain or branched divalent alkylene group containing 3 carbon atoms, and even more preferably isopropylidene (having the formula -CH2-CH(CH 3) -).

[0108] According to a particularly preferred embodiment, the silylated polymer is a polymer of the formula (III’), wherein:

[0109] -R 2 represents isopropylidene,

[0110] -R 5 represents methyl, and

[0111] -p is equal to 0.

[0112] In the presence of moisture, the alkoxysilyl groups of the polymer are converted to silanol groups, which then undergo reaction with other silanol groups to form covalent siloxane bonds between the individual polymer molecules, which ensures the formation of a crosslinked polymer network.

[0113] The number-average molecular weight of the moisture-crosslinkable polymer can vary from 1000 g / mol to 70000 g / mol, preferably from 5000 g / mol to 50000 g / mol, and more preferably from 10000 g / mol to 40000 g / mol.

[0114] The number-average molecular weight of the polymer can be measured by size exclusion chromatography (or SEC), which is also denoted by the term "gel permeation chromatography" (or GPC), preferably calibrated with polystyrene.

[0115] Relative to the total weight of the composition, the content of the moisture-crosslinkable polymer in the composition according to the invention can vary from 10% by weight to 60% by weight, preferably from 20% by weight to 55% by weight, more preferably from 30% by weight to 50% by weight.

[0116] In the context of the present invention, a range of values is understood to include the end values. For example, a range "between 10% and 60%" particularly includes the values 10% and 60%.

[0117] Unexpanded heat-expandable organic particles

[0118] Relative to the total weight of the composition, the composition according to the invention comprises at least 1% by weight, advantageously at least 3% by weight, of unexpanded thermally expandable organic particles.

[0119] "Unexpanded thermally expandable organic particles" means organic particles, preferably microspheres, which are expandable upon heating but are introduced unexpanded in the composition according to the invention. The particles are organic because they mainly contain organic compounds, i.e., compounds containing carbon and hydrogen atoms. In particular, relative to the total weight of the particles, the particles contain less than 21% by weight, preferably less than 11% by weight, of inorganic compounds.

[0120] Advantageously, the unexpanded thermally expandable organic particles comprise a thermoplastic polymer shell and a propellant embedded therein. Such particles are commercially available, for example under the trademark EXPANCEL®.

[0121] The propellant can be a liquid with a boiling temperature at most equal to the softening temperature of the thermoplastic polymer shell. Upon heating, the propellant evaporates and increases the internal pressure, while the shell softens, causing the particle to expand.

[0122] The propellant can comprise hydrocarbons (optionally chlorinated or fluorinated), such as n-pentane, isopentane, neopentane, n-butane, isobutane, n-hexane, isohexane, neohexane, n-heptane, isoheptane, n-octane, isooctane, petroleum ether, chloromethane, dichloromethane, dichloroethane, dichloroethylene, trichloroethane, trichloroethylene, trichlorofluoromethane or mixtures thereof.

[0123] Advantageously, the propellant accounts for 5% by weight to 40% by weight of the total weight of the particles.

[0124] Advantageously, the thermoplastic polymer shell is a polymer (homopolymer or copolymer) of at least one ethylenically unsaturated monomer, such as an ethylenically unsaturated monomer selected from nitrile-containing monomers (such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, fumaronitrile or crotonitrile), acrylates (such as methyl acrylate or ethyl acrylate), methacrylates (such as methyl methacrylate, isobornyl methacrylate or ethyl methacrylate), vinyl halides (such as vinyl chloride), vinylidene dihalides (such as vinylidene dichloride), vinyl pyridine, vinyl esters (such as vinyl acetate), styrene compounds (such as styrene, halogenated styrene or α-methylstyrene), dienes (such as butadiene, isoprene or chloroprene) and mixtures thereof. Preferably, the ethylenically unsaturated monomer comprises acrylonitrile, methacrylonitrile and / or methyl methacrylate, more preferably acrylonitrile and / or methacrylonitrile.

[0125] The thermoplastic polymer shell may also be a copolymer of at least one ethylenically unsaturated monomer and a crosslinking polyfunctional monomer as described above, such as a crosslinking polyfunctional monomer selected from divinylbenzene, ethylene glycol di(meth)acrylate, di(ethylene glycol) di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, glycerol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, triallyl formal tri(meth)acrylate, allyl methacrylate, trimethylolpropane tri(meth)acrylate, tributylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 3-acryloyloxy diol monoacrylate, triallyl formal, triallyl isocyanate, triallyl isocyanurate and mixtures thereof.

[0126] Advantageously, the thermoplastic polymer shell accounts for 60% to 95% by weight of the total weight of the particles.

[0127] In addition to the thermoplastic polymer shell and the propellant, relative to the total weight of the particles, the particles may contain up to 20% by weight of other substances, preferably up to 10% by weight. These other substances may be silica, chalk, bentonite, methylcellulose, guar gum, hydroxypropyl methylcellulose, carboxymethylcellulose, colloidal clay and / or salts, oxides or hydroxides of metals such as aluminum, calcium, magnesium, barium, iron, zinc, nickel and manganese (such as calcium phosphate, calcium carbonate, magnesium hydroxide, barium sulfate, calcium oxalate, hydroxides of aluminum, iron, zinc, nickel or manganese).

[0128] Advantageously, the unexpanded thermally expandable organic particles start to expand at a temperature of at least 90 °C, preferably between 90 °C and 220 °C, more preferably between 90 °C and 180 °C, and even more preferably between 90 °C and 150 °C. This temperature can be measured using thermomechanical analysis (e.g., performed on a thermomechanical analyzer), in particular by heating the unexpanded thermally expandable organic particles to be tested at a constant rate of 20 °C / min and recording their volume as a function of temperature. The temperature at which the particles start to expand depends on the composition of the shell and the blowing agent.

[0129] The average particle size Dv50 of the unexpanded thermally expandable organic particles can vary from 1 μm to 200 μm, preferably from 3 μm to 100 μm, more preferably from 5 μm to 50 μm. This average particle size Dv50 corresponds to the maximum size of the smallest 50% by volume of the particles and can be measured by laser diffraction (e.g., low angle laser light scattering).

[0130] Advantageously, the amount of unexpanded thermally expandable organic particles in the composition according to the invention is at least 3% by weight, preferably from 3% to 18% by weight, more preferably from 5% to 15% by weight, for example from 6% to 12% by weight, relative to the total weight of the composition.

[0131] Inorganic filler

[0132] The composition according to the invention contains at least 20% by weight of inorganic filler relative to the total weight of the composition.

[0133] For example, the inorganic filler can be any inorganic filler commonly used in the field of sealants. These fillers are in the form of particles of various geometric shapes. They can be, for example, spherical, fibrous or of irregular shape.

[0134] Advantageously, the inorganic filler is selected from clay, quartz, hollow mineral microspheres, carbonated fillers and mixtures thereof, preferably selected from carbonated fillers.

[0135] The clay can be selected from talc, montmorillonite, kaolinite, vermiculite and mixtures thereof, especially talc.

[0136] The mineral hollow microspheres can be hollow glass microspheres, especially made of borosilicate or aluminosilicate of sodium and calcium.

[0137] Advantageously, the carbonated filler is selected from alkali metal or alkaline earth metal carbonates and mixtures thereof. Preferably, the carbonated filler contains calcium carbonate, more preferably, the carbonated filler is ground calcium carbonate (GCC) or precipitated calcium carbonate (PCC), which is optionally coated with a fatty acid (especially a calcium salt of a fatty acid), and even more preferably, the carbonated filler is precipitated calcium carbonate coated with a fatty acid (especially a calcium salt of a fatty acid).

[0138] When calcium carbonate is coated with a fatty acid, this imparts all or part of the hydrophobicity to the calcium carbonate particles. In addition, the fatty acid coating acts as a hydrophobic coating, which can help prevent the calcium carbonate from absorbing the components of the composition and rendering them ineffective. The hydrophobic coating of the calcium carbonate can account for 0.1% to 3.5% by weight relative to the total weight of the calcium carbonate.

[0139] Preferably, the fatty acid coating the calcium carbonate contains more than 50% by weight of stearic acid relative to the total weight of the fatty acid or consists of more than 50% by weight of stearic acid relative to the total weight of the fatty acid.

[0140] The average particle size of the inorganic filler can vary between 10 nm and 400 μm, preferably between 20 nm and 100 μm, more preferably between 30 nm and 1 μm, and even more preferably between 40 nm and 300 nm.

[0141] The average particle size advantageously corresponds to the particle size Dv50, i.e., the maximum size of the smallest 50% by volume of the particles, and can be measured by laser diffraction on a MALVERN-type device (for example, according to ISO 13320).

[0142] Unless otherwise stated, the standards mentioned throughout this application are the standards in force on the date of filing of this application.

[0143] Relative to the total weight of the composition, the content of the inorganic filler in the composition according to the invention is advantageously 20% to 70% by weight, preferably 30% to 60% by weight, and more preferably 35% to 50% by weight.

[0144] Crosslinking catalyst

[0145] The composition according to the invention may further comprise a crosslinking catalyst.

[0146] The crosslinking catalyst can be any catalyst known to those skilled in the art for silanol condensation or for polyurethane crosslinking.

[0147] As crosslinking catalysts for silanol condensation, the following examples can be cited:

[0148] - Organic derivatives of titanium, such as titanium acetylacetonate, tetrapropoxytitanium, tetrabutoxytitanium;

[0149] - Organic derivatives of zirconium, such as zirconium acetylacetonate, tetrapropoxyzirconium, tetrabutoxyzirconium;

[0150] - Aluminum, such as aluminum chelates (e.g., K-KAT® 5218 from KING INDUSTRIES);

[0151] - amines such as 1,8 - diazabicyclo[5.4.0]undec - 7 - ene (DBU), 1,5 - diazabicyclo[4.3.0]non - 5 - ene (DBN), diethyl ether - 2,2'-morpholine (DMDEE), 1,4 - diazabicyclo[2.2.2]octane (DABCO), 1,5,7 - triazabicyclo[4.4.0]dec - 5 - ene (TBD);

[0152] - zinc carboxylate - based catalysts (e.g., K - KAT®670 from KING INDUSTRIES);

[0153] - tin - based catalysts such as compounds derived from dioctyltin or dibutyltin, especially dioctyloxide, dioctyltin diacetate, dioctyltin dilaurate, dioctyltin dicarboxylate, dibutyltin diacetylacetonate (CAS: 22673 - 19 - 4), dibutyltin dilaurate (DBTDL), dibutyltin diacetate or dibutyloxide, preferably dibutyltin diacetylacetonate;

[0154] - guanidine derivatives such as 1 - (o - tolyl)biguanide (CAS: 93 - 69 - 6), e.g., Rhenocure 1000C (supplied by RheinChemie Additives).

[0155] As cross - linking catalysts for polyurethane cross - linking, the following examples can be cited:

[0156] - carboxylates of bismuth and / or zinc, especially neodecanoates;

[0157] - amines such as DABCO or DMDEE;

[0158] - organic derivatives of titanium such as titanium acetylacetonate, tetrapropoxytitanium, tetrabutoxytitanium;

[0159] - organic derivatives of zirconium such as zirconium acetylacetonate, tetrapropoxyzirconium, tetrabutoxyzirconium;

[0160] - tin - based catalysts such as compounds derived from dioctyltin or dibutyltin (especially dibutyltin dilaurate or dioctyltin).

[0161] Preferably, the cross - linking catalyst is a tin - based catalyst, preferably selected from compounds derived from dioctyltin and dibutyltin, especially compounds derived from the dioctyltin and dibutyltin catalysts as described above.

[0162] Relative to the total weight of the composition, the content of the cross - linking catalyst in the composition according to the invention is advantageously from 0.01% to 5% by weight, preferably from 0.05% to 2% by weight, more preferably from 0.1% to 1% by weight.

[0163] Adhesion promoter

[0164] The composition according to the invention may further comprise an adhesion promoter.

[0165] The adhesion promoter may be selected from amino-, mercapto- and epoxy-alkoxysilanes, and mixtures thereof. Preferably, the adhesion promoter is selected from aminoalkoxysilanes, more preferably from aminotrialkoxysilanes, and even more preferably from aminotrimethoxysilanes, such as (3-aminopropyl)trimethoxysilane.

[0166] As an example of an epoxy-alkoxysilane, mention may be made of (3-glycidoxypropyl)trimethoxysilane (also known as GLYMO).

[0167] Advantageously, the aminotrimethoxysilane is formed by the group consisting of 4-amino-3,3-dimethylbutyltrimethoxysilane, (3-aminopropyl)trimethoxysilane and N-(3-(trimethoxysilyl)propyl)ethylenediamine. Preferably, the aminotrimethoxysilane is (3-aminopropyl)trimethoxysilane.

[0168] Relative to the total weight of the composition according to the invention, the adhesion promoter content may be from 0.1% by weight to 5% by weight, preferably from 0.5% by weight to 3% by weight.

[0169] Other additives

[0170] The composition according to the invention may further comprise one or more additives selected from moisture scavengers, pigments, plasticizers, solvents, rheology modifiers, UV stabilizers (or antioxidants) and mixtures thereof.

[0171] Advantageously, the composition according to the invention comprises a mixture of additives selected from moisture scavengers, pigments and UV stabilizers (or antioxidants).

[0172] Relative to the total weight of the composition, the total content of additives in the composition according to the invention may vary between 0.5% by weight and 20% by weight, preferably between 2% by weight and 15% by weight, more preferably between 3% by weight and 10% by weight.

[0173] Advantageously, the composition according to the invention comprises a moisture scavenger.

[0174] Suitable moisture scavengers (or desiccants) are in particular alkoxysilanes, such as trialkoxysilanes (especially trimethoxysilane). The moisture scavenger advantageously extends the shelf life of the composition according to the invention during storage and transportation before its use.

[0175] Advantageously, the moisture scavenger is selected from vinyltrimethoxysilane, trimethoxymethylsilane, propyltrimethoxysilane, vinyltriethoxysilane, alkoxyarylsilanes (such as GENIOSIL® XL 70 sold by WACKER), and mixtures thereof.

[0176] Preferably, the moisture scavenger is selected from vinyltrimethoxysilane, vinyltriethoxysilane, and mixtures thereof, more preferably vinyltrimethoxysilane.

[0177] The moisture scavenger content can be from 0.1 wt% to 5 wt%, preferably from 0.5 wt% to 3 wt%, based on the total weight of the composition according to the invention.

[0178] Advantageously, the composition according to the invention comprises a pigment.

[0179] The pigment can be an organic or inorganic pigment, such as titanium dioxide (e.g., Kronos 2066 from Kronos), carbon black (e.g., PRINTEX® 25 from Orion), or manganese ferrite (e.g., BAYFERROX® 303T from LANXESS), preferably titanium dioxide. TM The pigment content can be up to 5 wt%, preferably up to 3 wt%, based on the total weight of the composition according to the invention.

[0180] The composition according to the invention can comprise a plasticizer.

[0181] The plasticizer can be any plasticizer commonly used in the field of sealants.

[0182] Advantageously, the plasticizer is selected from:

[0183] - Diisodecyl phthalate (such as PALATINOL® DIDP sold by BASF),

[0184] - Diisononyl phthalate (DINP) (such as PALATINOL® N sold by BASF),

[0185] - Esters of alkylsulfonic acids and phenols (such as MESAMOLL® sold by LANXESS),

[0186] - Diisononyl 1,2 - cyclohexanedicarboxylate (such as HEXAMOLL DINCH® sold by BASF),

[0187] - Pentaerythritol tetrapentanoate (such as PEVALENTM sold by PERSTORP), and

[0188] - Mixtures thereof.

[0189]

[0190] ​The plasticizer content can be up to 15% by weight, preferably up to 10% by weight, relative to the total weight of the composition according to the invention.

[0191] The composition according to the invention may comprise from 0% to 5% by weight of a solvent relative to the total weight of the composition according to the invention. Preferably, the solvent is volatile at room temperature (a temperature of about 23 °C). For example, the volatile solvent may be selected from alcohols that are volatile at room temperature, such as ethanol or isopropanol. The volatility of the solvent results in the joint obtained after curing the composition containing no solvent.

[0192] "About X" means greater than or less than the X value by 10%.

[0193] The composition according to the invention may comprise a rheological agent.

[0194] The rheological agent may be any rheological agent commonly used in the field of adhesive and / or sealant compositions.

[0195] Advantageously, the rheological agent is selected from:

[0196] - PVC plastisols, corresponding to suspensions of PVC in plasticizers miscible with PVC, obtained in situ by heating at a temperature in the range of 60 °C to 80 °C. These plastisols may be those described in particular in "Polyurethane Sealants", Robert M. Evans, ISBN 087762 - 998 - 6.

[0197] - Fumed silica, such as HDK® N20 from WACKER,

[0198] - Urea derivatives produced by the reaction of aromatic diisocyanate monomers such as 4,4'-MDI with aliphatic amines such as butylamine,

[0199] - Amide waxes, preferably micronized amide waxes, such as CRAYVALLAC® SLX, CRAYVALLAC® SLW or CRAYVALLAC® SUPER from Arkema, or THIXATROL® AS8053 or THIXATROL® MAX (EC No: 432 - 430 - 3) obtainable from ELEMENTIS, or even RHEOBYK 7503 from BYK, and

[0200] - Mixtures thereof.

[0201] "Amide wax" means a wax containing one or more compounds having at least one amide group. In particular, amide waxes can be obtained from fatty acids (such as ricinoleic acid) and (di)amines.

[0202] "Micronization" means an average particle size of less than 1 mm, advantageously less than 500 μm, preferably less than 100 μm, and more preferably less than 10 μm.

[0203] The average particle size advantageously corresponds to the particle size Dv50, i.e., the maximum size of the smallest 50% of the particles by volume, and can be measured with a particle size analyzer, in particular by laser diffraction measurement on a device of the MALVERN type. (For example, according to standard ISO13320).

[0204] The content of the rheological agent can be up to 15% by weight, preferably up to 10% by weight, relative to the total weight of the composition according to the invention.

[0205] Advantageously, the composition according to the invention contains a UV stabilizer (or antioxidant). UV stabilizers are generally introduced to protect the composition from degradation due to reaction with oxygen, which may be formed by the action of heat or light. These compounds can include antioxidants capable of scavenging free radicals.

[0206] Advantageously, the UV stabilizer (or antioxidant) is selected from benzotriazoles, benzophenones, hindered phenols such as octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (CAS: 2082-79-3), pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (CAS: 6683-19-8) or ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate] (CAS: 36443-68-2), hindered amines (HALS also known as "hindered amine light stabilizers") such as bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate (CAS: 41556-26-7), methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate (CAS: 82919-37-7) or 4,4'-bis(α,α-dimethylbenzyl) diphenylamine, and mixtures thereof.

[0207] Preferably, the UV stabilizer (or antioxidant) is selected from hindered phenols, hindered amines and mixtures thereof, more preferably from hindered phenols.

[0208] Hindered phenols are generally phenols preferably substituted at the ortho position of the hydroxyl group by at least one bulky group (such as a tert-butyl group).

[0209] The content of the UV stabilizer (or antioxidant) can be from 0.1% to 5% by weight, preferably from 0.5% to 3% by weight, relative to the total weight of the composition according to the invention.

[0210] Other features of the composition according to the invention

[0211] The composition according to the invention can be a one-component composition or a two-component composition, preferably a one-component composition.

[0212] According to a preferred embodiment, the composition according to the invention is a one-component composition, which comprises:

[0213] - a moisture-crosslinkable polymer in an amount of 10% to 60% by weight, preferably a silylated polymer,

[0214] - at least 3% by weight of unexpanded thermally expandable organic particles, which preferably start to expand at a temperature of at least 90 °C,

[0215] - an inorganic filler in an amount of 20% to 70% by weight, preferably selected from carbonated fillers,

[0216] - a crosslinking catalyst in an amount of 0.01% to 5% by weight,

[0217] - an adhesion promoter in an amount of 0.1% to 5% by weight, and

[0218] - optionally one or more additives in an amount of 0.5% to 20% by weight, selected from moisture scavengers, pigments, plasticizers, solvents, rheology modifiers, UV stabilizers (or antioxidants) and mixtures thereof,

[0219] The weight percentages are relative to the total weight of the composition.

[0220] Preferably, the one-component composition according to the invention consists essentially of the above components. "Consisting essentially of" means that the composition contains less than 5% by weight, preferably less than 2% by weight, even more preferably less than 1% by weight, of components other than the above components relative to the total weight of the composition.

[0221] The components of this embodiment and their specific contents are as described above, including the embodiment and the preferred features.

[0222] In particular, the composition according to the invention is a one-component composition, which comprises:

[0223] - a moisture-crosslinkable polymer in an amount of 30% to 50% by weight, preferably a silylated polymer of formula (II") or (III'),

[0224] - unexpanded thermally expandable organic particles in an amount of 5% to 15% by weight, which preferably comprise a thermoplastic polymer shell, which is a polymer of at least one ethylenically unsaturated monomer, and a propellant containing hydrocarbons, and the unexpanded thermally expandable organic particles preferably start to expand at a temperature of at least 90 °C,

[0225] - 35 wt% to 50 wt% of an inorganic filler, preferably ground calcium carbonate or precipitated calcium carbonate, optionally coated with a fatty acid,

[0226] - 0.1 wt% to 1 wt% of a crosslinking catalyst, preferably a tin-based catalyst,

[0227] - 0.5 wt% to 3 wt% of an adhesion promoter, preferably selected from aminotrimethoxysilane, and

[0228] - Optionally 3 wt% to 10 wt% of one or more additives selected from moisture scavengers, pigments, plasticizers, solvents, rheology modifiers, UV stabilizers (or antioxidants) and mixtures thereof,

[0229] The weight percentages are relative to the total weight of the composition.

[0230] Preferably, the one-component composition according to the invention consists essentially of the above components.

[0231] The components of this embodiment and their specific contents are as described above, including the embodiment and preferred features.

[0232] According to another embodiment, the composition according to the invention is a two-component composition comprising component A and component B, wherein the composition comprises:

[0233] - In component A and / or B, preferably in component A, 10 wt% to 60 wt% of a moisture-crosslinkable polymer, provided that if the moisture-crosslinkable polymer in component A is a polyurethane with -NCO end groups, the moisture-crosslinkable polymer is preferably a silylated polymer,

[0234] - In component A and / or B, preferably in component B, at least 3 wt% of unexpanded heat-expandable organic particles, the unexpanded heat-expandable organic particles preferably starting to expand at a temperature of at least 90 °C,

[0235] - In component A and / or B, preferably in component B, 20 wt% to 70 wt% of an inorganic filler, the inorganic filler preferably selected from carbonated fillers,

[0236] - 0.01 wt% to 5 wt% of a crosslinking catalyst in component A,

[0237] - In component A and / or B, preferably in component A, 0.1 wt% to 5 wt% of an adhesion promoter,

[0238] - 0.0015 wt% to 0.55 wt% of water in component B, and

[0239] - Optionally, one or more additives in an amount of 0.5% to 20% by weight, said additives being selected from moisture scavengers, pigments, plasticizers, solvents, rheological agents, UV stabilizers (or antioxidants) and mixtures thereof, said additives being in component A and / or B, preferably in component A,

[0240] said percentages by weight being relative to the total weight of the composition, and

[0241] the weight ratio of component A to component B is preferably from 10 to 30.

[0242] Preferably, the two-component composition according to the invention consists essentially of the above components.

[0243] The components of this embodiment and their specific contents are as described above, including the embodiments and preferred features.

[0244] In particular, the composition according to the invention is a two-component composition comprising component A and component B, wherein the composition comprises:

[0245] - In component A and / or B, preferably in component A, 30% to 50% by weight of a moisture-crosslinkable polymer, provided that if the moisture-crosslinkable polymer in component A is a polyurethane having -NCO end groups, the moisture-crosslinkable polymer is preferably a silylated polymer of formula (II”) or (III’),

[0246] - In component A and / or B, preferably in component B, 5% to 15% by weight of unexpanded thermally expandable organic particles, said unexpanded thermally expandable organic particles preferably comprising a thermoplastic polymer shell which is a polymer of at least one ethylenically unsaturated monomer, and a propellant comprising a hydrocarbon, and said unexpanded thermally expandable organic particles preferably starting to expand at a temperature of at least 90 °C,

[0247] - In component A and / or B, preferably in component B, 35% to 50% by weight of an inorganic filler, said inorganic filler being preferably ground calcium carbonate or precipitated calcium carbonate, optionally coated with a fatty acid,

[0248] - 0.1% to 1% by weight of a crosslinking catalyst in component A, said crosslinking catalyst being preferably a tin-based catalyst,

[0249] - 0.5% to 3% by weight of an adhesion promoter in component A and / or B, preferably in component A, said adhesion promoter being preferably selected from aminotrimethoxysilane,

[0250] - 0.03% to 0.3% by weight of water in component B, and

[0251] - Optionally, 3% to 10% by weight of one or more additives selected from moisture scavengers, pigments, plasticizers, solvents, rheological agents, UV stabilizers (or antioxidants) and mixtures thereof, said additives being in component A and / or B, preferably in component A,

[0252] Said weight percentages are relative to the total weight of the composition, and

[0253] The weight ratio of component A to component B is preferably from 10 to 30.

[0254] Preferably, the two-component composition according to the invention consists essentially of the above ingredients.

[0255] The ingredients of this embodiment and their specific contents are as described above, including the embodiments and preferred features.

[0256] Advantageously, the composition according to the invention has a shear strength comprised between 1 MPa and 5 MPa, preferably between 1.0 MPa and 3 MPa.

[0257] The shear strength of the composition according to the invention is advantageously measured 14 days after curing the composition under standard conditions (e.g. 23 °C ± 2 °C, 50% RH ± 5% RH). A person skilled in the art knows how to measure the shear strength. In particular, the shear strength can be measured as described in Example 1 below.

[0258] The composition according to the invention can be prepared by simply mixing its ingredients. An example of the preparation of the composition according to the invention is described in Example 1.

[0259] The composition according to the invention is preferably stored in an anhydrous environment, for example in an airtight package, wherein the composition is protected from humidity and preferably protected from light.

[0260] Method for bonding substrates

[0261] The invention also relates to a method for bonding substrates, comprising the steps of:

[0262] - Coating at least one surface of a substrate with the composition according to the invention as described above (including the embodiments and preferred features), and then

[0263] - Bringing the substrates into contact.

[0264] It should be understood that during the coating step and the contact step, the composition according to the invention is in an uncured state.

[0265] The substrates can be the same or different.

[0266] Preferably, the two substrates are bonded together.

[0267] The substrates to be implemented are diverse and are advantageously made of plastic, metal, and / or composite materials. Preferably, at least one of the substrates is made of a metallic material, and more preferably, the substrates are made of a metallic material.

[0268] The plastic material can be a polyolefin, such as polyethylene or polypropylene, or a polyester.

[0269] The metallic material can be pure or an alloy and is advantageously aluminum or steel, preferably aluminum.

[0270] The composite material can be a reinforced plastic material, such as a fiber-reinforced plastic, especially a sheet molding compound (SMC). The fibers in the fiber-reinforced plastic can be glass, carbon, aramid, or basalt fibers, preferably glass fibers. The fiber length can vary between 6 mm and 50 mm. The polymer in the reinforced plastic material can be a polyester, polyolefin, epoxy resin, or vinyl ester resin, preferably a polyester or polyolefin (such as polyethylene or polypropylene). The polymer in the reinforced plastic material is preferably unsaturated. The reinforced plastic material can include other compounds (such as fillers and / or catalysts) in addition to the fibers and polymer. Preferably, the reinforced plastic material is SMC, especially glass fiber-reinforced unsaturated polyester.

[0271] According to a preferred embodiment, the substrates to be bonded are a battery cover and a battery container, especially for a motor vehicle.

[0272] Advantageously, the method for bonding substrates according to the present invention does not include the step of applying a primer to one or more substrates before the coating step.

[0273] Advantageously, the method for bonding substrates according to the present invention does not include surface treatment of one or more substrates before the coating step.

[0274] "Bringing the substrates into contact" means that the substrates are in contact via the composition according to the present invention sandwiched between them.

[0275] Once the substrates are in contact, the total thickness of the composition according to the present invention between the substrates can be 1 mm to 15 mm, preferably 2 mm to 10 mm.

[0276] Advantageously, the method for bonding substrates according to the present invention further includes the step of embedding a heating element in the composition according to the present invention. Preferably, this step is carried out before and / or simultaneously with the step of bringing the substrates into contact. Thus, the composition is in an uncured state during the embedding step.

[0277] This step can be carried out by:

[0278] - Place a heating element on a composition according to the invention of a first thickness, said composition coating at least one surface of a first substrate, and then

[0279] - Bring the heating element into contact with a composition according to the invention of a second thickness.

[0280] The step of bringing the heating element into contact with the composition of the second thickness can be carried out by directly coating the composition onto the heating element or by contacting a second substrate having at least one surface coated with the composition of the second thickness.

[0281] Thus, according to an embodiment, a method for bonding substrates according to the invention comprises the following steps:

[0282] - Coating at least one surface of a first substrate with a composition according to the invention of a first thickness, and then

[0283] - Place a heating element on the composition of the first thickness, and then

[0284] - Bring the heating element into contact with a composition according to the invention of a second thickness, and

[0285] - Bring the substrates into contact.

[0286] Advantageously, the thickness of the heating element is at least four times smaller, preferably at least eight times smaller, and more preferably at least ten times smaller than the thickness of the composition according to the invention between the substrates. The thickness of the heating element can be less than 0.7 mm, preferably less than 0.5 mm, and more preferably less than 0.3 mm.

[0287] The length and width of the heating element can be adjusted to fit the length and width of the composition according to the invention, i.e., suitable for providing sufficient heat throughout the composition. Preferably, the heating element is completely coated with the composition according to the invention.

[0288] Preferably, the heating element is an electric heating element, i.e., it provides heat when an electric current is applied.

[0289] The heating element can be one or more electric heating wires, one or more electric heating ribbons, and / or one or more electric heating strips, such as interwoven electric heating wires.

[0290] The heating element can be connected to a connector, which can be further connected to a heating power controller. The heating power controller is a device that can adjust the heating temperature of the heating element. For example, when the heating element is an electric heating element, the heating power controller can have a tuning switch to adjust the heating temperature by tuning the magnitude of the current. The heating power controller can also have a tuning switch to set the heating time.

[0291] Thus, the connector enables the heating element to be easily connected and disconnected from the heating power controller when needed.

[0292] Optionally, after bringing the substrates into contact, the substrates can be further fastened by fastening means such as bolts and / or rivets. Preferably, this step is carried out when the composition according to the invention is not fully cured.

[0293] When implementing the fastening means and the heating element, the heating element advantageously includes a hole for the fastening means to pass through the heating element.

[0294] After bringing the substrates into contact, the composition according to the invention is advantageously cured. Preferably, the curing is carried out at a temperature between 15 °C and 50 °C, more preferably between 18 °C and 30 °C, and at a relative humidity between 30% and 80%, more preferably between 40% and 70%. The curing time depends on the type and thickness of the composition (for example, a one-component composition cures more slowly than a two-component composition), temperature, and relative humidity.

[0295] Article

[0296] The invention further relates to an article comprising a (cured or uncured) composition according to the invention as described above (including embodiments and preferred features), the composition bonding at least two substrates of the article.

[0297] An article can be obtained due to the method for bonding substrates according to the invention.

[0298] The substrates are preferably as described above for the method for bonding substrates according to the invention (including embodiments and preferred features), in particular the substrates are made of a metallic material.

[0299] According to a preferred embodiment, the article is a battery housing comprising a lid and a container (especially for a motor vehicle), and the composition according to the invention bonds the lid and the container.

[0300] The total thickness of the composition according to the invention between the substrates can be from 1 mm to 15 mm, preferably from 2 mm to 10 mm.

[0301] Advantageously, the article further comprises a heating element embedded in the composition according to the invention. Once the composition according to the invention is cured, the heating element enables the composition to be easily heated, such that the thermally expandable organic particles expand and the composition breaks, and thus the substrates can be easily separated and the article can be easily disassembled.

[0302] The heating element is characterized as described above for the method for bonding substrates according to the invention (in particular, thickness, width, length, structure, etc.) (including embodiments and preferred features).

[0303] The heating element can be connected to a connector, which can be further connected to a heating power controller, as described above for the method for bonding substrates according to the invention (including embodiments and preferred features).

[0304] Optionally, the article according to the invention may include fastening means, such as bolts and / or rivets. The fastening means are used to further fasten the substrates bonded by the composition according to the invention.

[0305] When implementing the fastening means and the heating element, the heating element advantageously includes a hole for the fastening means to pass through the heating element.

[0306] An example of an article of a battery housing containing the composition according to the invention and further containing a heating element and bolts is shown in Figure 1 .

[0307] An embodiment of an embedded heating wire with holes is shown in Figure 2 .

[0308] Method for separating substrates

[0309] The present invention relates to a method for separating substrates, which includes a heating step.

[0310] First embodiment

[0311] According to a first embodiment, the method for separating substrates includes a heating step of the article according to the invention.

[0312] The article according to the invention is as described above, including embodiments and preferred features.

[0313] Preferably, the heating step is carried out in the region where the composition according to the invention is located. This enables the heating area to be restricted, which is advantageous for articles such as battery housings, since the components inside the housing are not heated.

[0314] When the article contains a heating element embedded in the composition according to the invention, this can be easily achieved. Other devices such as hot air guns can be used to heat the composition, but the embedded heating element is preferred.

[0315] Therefore, the article preferably contains a heating element embedded in the composition according to the invention.

[0316] When the article includes fastening means (such as bolts and / or rivets), the heating step can be carried out before or after removing them, usually after removing them.

[0317] The heating step is advantageously carried out at a temperature and for a period of time sufficient to break the composition according to the invention.

[0318] The heating step can be carried out at a temperature of at least 120 °C, preferably 120 °C to 250 °C, more preferably 150 °C to 220 °C.

[0319] The heating step can be carried out for 30 min or less, preferably 20 min or less, more preferably 5 min to 20 min.

[0320] After the heating step, the substrate of the article (which is bonded via the composition according to the invention) can be easily separated, especially manually.

[0321] Second embodiment

[0322] According to the second embodiment, the method for separating the substrate includes the steps of the method for bonding the substrate according to the invention as described above (including the embodiments and preferred features), followed by a heating step. In particular, the method for bonding the substrate advantageously includes the step of embedding a heating element in the composition, as described above (including the embodiments and preferred features).

[0323] The heating step is as described above for the first embodiment, including the embodiments and preferred features. In particular, the heating step is preferably carried out in the region where the composition according to the invention is located.

[0324] When the method for bonding the substrate includes the step of fastening the substrate by fastening means (such as bolts and / or rivets), the heating step can be carried out before or after removing them, usually after removing them.

[0325] As for the first embodiment, the substrate (which is bonded by the composition according to the invention) can be easily separated after the heating step, especially manually.

[0326] In particular, the method for separating the substrate according to this second embodiment includes the following steps:

[0327] - Coating at least one surface of the substrate with the composition according to the invention as described above (including the embodiments and preferred features), and then

[0328] - bringing the substrates into contact, and then

[0329] - curing the composition, and then

[0330] - heating the composition,

[0331] The method preferably includes the step of embedding a heating element in the composition according to the invention before and / or simultaneously with the step of bringing the substrates into contact.

[0332] Preferably, the method for separating substrates according to this second embodiment includes the following steps:

[0333] - Coating a first thickness of the composition according to the invention as described above (including embodiments and preferred features) on at least one surface of a first substrate, and then

[0334] - Placing a heating element on the composition of the first thickness, and then

[0335] - bringing the heating element into contact with a second thickness of the composition according to the invention,

[0336] - bringing the substrates into contact, and then

[0337] - curing the composition, and then

[0338] - heating the composition.

[0339] Use of the composition according to the invention

[0340] The invention further relates to the use of the composition according to the invention as an adhesive or a sealant, preferably as a sealant.

[0341] Preferably, the composition according to the invention is used for sealing the substrates as described above (including embodiments and preferred features) in the method for bonding substrates according to the invention.

[0342] According to a preferred embodiment, the composition according to the invention is used for sealing the lid and the container of a battery housing, in particular for a motor vehicle.

[0343] Furthermore, the invention relates to the use of the composition according to the invention for manufacturing an article comprising a thermally separable substrate.

[0344] Preferably, the article comprising a thermally separable substrate is the article according to the invention as described above, including embodiments and preferred features.

[0345] All of the above embodiments can be combined with each other. In particular, the various foregoing components in the composition, and especially the preferred embodiments, can be combined with each other. Description of the Drawings

[0346] Figure 1Shows one embodiment, but is not limited thereto, of an article that is a battery housing (10) including a lid (30) and a container (40), and a composition (60) according to the present invention bonds the lid (30) and the container (40). The battery housing (10) further includes bolts (50, 51, 52, 53, 54, 55) and a heating element (70) embedded in the composition (60), and the heating element (70) is connected to a connector (20). The leftmost bolt (50) is depicted to show its complete shape, but it passes through the edges of the lid (30) and the container (40), the composition (60), and the heating element (70) like the other bolts (51, 52, 53, 54, 55). When the heating element (70) is completely coated by the composition (60), it cannot be seen from the outside.

[0347] Figure 2 Shows a top view of one embodiment (but is not limited thereto) of a heating wire (71) embedded in a composition (60) according to the present invention. The heating wire (71) has holes (80) for passing through fastening means and is connected to a connector (20). When the heating wires (71) are completely coated by the composition (60), they cannot be seen from the outside.

[0348] The following examples illustrate the present invention without limiting it.

[0349] Examples

[0350] Example 1: Materials and methods

[0351] Materials

[0352] The following materials were implemented:

[0353] - MS POLYMER commercialized by KANEKA TM S203H: A polypropylene oxide end-capped with dimethoxysilyl and having a viscosity (Brookfield) of 6 - 10 Pa·s at 23°C, a polymer that can be crosslinked by moisture;

[0354] - MS POLYMER commercialized by KANEKA TM SAX400: A polyether end-capped with methyldimethoxysilyl and having a viscosity (Brookfield) of 19.5 - 28.5 Pa·s at 23°C, a polymer that can be crosslinked by moisture;

[0355] - Expancel® 043DU80 commercialized by Nouryon: Microspheres having a thermoplastic shell and a core containing a blowing agent and having an average particle size Dv50 of 16 - 24 μm (measured by laser diffraction, low-angle laser light scattering), unexpanded thermally expandable organic particles;

[0356] - DYNASYLAN® VTMO commercialized by EVONIK: Vinyltrimethoxysilane (CAS: 2768-02-7), moisture scavenger;

[0357] - DYNASYLAN® AMMO commercialized by EVONIK: (3-Aminopropyl)trimethoxysilane (CAS: 13822-56-5), adhesion promoter;

[0358] - Kronos 2066 commercialized by Kronos TM Titanium dioxide, pigment;

[0359] - CALOFORT® SV commercialized by Specialty Minerals: Precipitated calcium carbonate coated with calcium stearate, with an average particle size of 0.07 μm, inorganic filler;

[0360] - Irganox® 245 commercialized by BASF: Ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate] (CAS: 36443-68-2), antioxidant;

[0361] - TIB KAT® 226 commercialized by TIB Chemicals: Bis(2,4-pentanedionato)dibutyltin (CAS: 22673-19-4), catalyst.

[0362] Preparation of compositions A - E

[0363] Compositions A - E are prepared by mixing (speedmixer DAV 400) the components indicated in Table 1 at room temperature, for example 18°C - 25°C (the temperature in the mixture may rise during its preparation due to frictional shear), and at atmospheric pressure. Load MSPOLYMER TM , Expancel® (when present), VTMO, Irganox ® 245 and Kronos TM 2066 into the mixing cup and mix first (for example, mix at about 2000 rpm (revolutions per minute) for about 2 minutes). Then load CALOFORT® SV (when present) and mix (for example, at about 2000 rpm for about 3 minutes). Then add AMMO and TIB KAT 226 to the cup and mix under vacuum (for example, mix at about 2000 rpm, at a pressure of about 20 kPa for about 2 minutes). After their preparation, the compositions are stored in a sealed box until their properties are evaluated.

[0364] Shear strength

[0365] The shear strength was measured on a standard anodized aluminum 6061 substrate. Shear strength specimens were prepared by bonding two anodized aluminum plates (100 mm * 25 mm * 2 mm), with an overlap of 12.5 mm * 25 mm * 2 mm of the adhesive size (with the composition to be tested). The shear specimens were placed under standard conditions (23 °C ± 2 °C, 50% RH ± 5% RH (RH represents relative humidity)) for 14 days and then pulled on an Instron machine at 50 mm / min. The shear strength was then calculated by dividing the tensile force required to break the specimen by the square of 12.5 mm * 25 mm.

[0366] Properties after heating

[0367] The composition to be tested with a thickness of about 2 mm was applied to the first aluminum piece, and then intertwined electric heating wires (with a thickness less than 0.3 mm) were placed on the uncured composition and covered with a composition of about 2 mm thickness. Then the second aluminum piece was pressed down onto the uncured composition. Thus, the heating wires were embedded in the uncured composition (with a total thickness of about 4 mm), which was sandwiched between two aluminum pieces (the aluminum pieces being anodized aluminum 6061).

[0368] The composition was cured for two weeks under standard conditions (23 °C ± 2 °C, 50% RH ± 5% RH). Then a heating power controller (with a tuning switch to adjust the heating temperature by tuning the magnitude of the current, and a tuning switch to set the heating time) was connected to the heating wires, and the temperature was raised to 200 °C for 10 min - 15 min and then stopped.

[0369] The structure of the composition was visually evaluated, and it was tested whether the two aluminum pieces could be easily separated manually.

[0370] Example 2: The compositions according to the invention and comparative compositions

[0371] Compositions A - E were prepared with the ingredients shown in Table 1 as described in Example 1 (“Preparation of Compositions A - E”), and the percentages are weight percentages relative to the total weight of the composition.

[0372]

[0373] Table 1: Ingredients of Compositions A - E

[0374] Then their properties (“shear strength” and “properties after heating”) were evaluated as described in Example 1, and the results are shown in Table 2.

[0375]

[0376] Table 2 : Properties of Compositions A - E

[0377] The combination of inorganic filler and thermally expandable organic particles enables easy separation of two aluminum parts after heating, while maintaining a sufficiently high shear strength before heating (comparing Compositions B and C according to the invention with Comparative Compositions D and E).

[0378] A similar effect was observed for Composition A according to the invention, which is based on another moisture - crosslinkable polymer.

[0379] Thus, the compositions according to the invention enable an effective sealing structure to be provided (especially for a battery housing shell, where the composition is applied between the lid and the container), which can be easily disassembled if necessary (e.g., for repair or maintenance operations).

Claims

1. A composition comprising: - a moisture-crosslinkable polymer, - at least 3% by weight of unexpanded thermally expandable organic particles, and - at least 20% by weight of an inorganic filler, The weight percentages being relative to the total weight of the composition.

2. The composition according to claim 1, wherein the moisture-crosslinkable polymer is selected from polyurethanes having -NCO end groups, silylated polymers, and mixtures thereof, preferably selected from silylated polymers and mixtures thereof.

3. The composition according to claim 2, wherein the silylated polymer has the formula (II), (III) or (IV): ， Wherein: -R 4 , R 5 and p have the same meanings as in formula (I) above, - P represents a saturated or unsaturated polymeric group having a straight or branched open chain, or comprising one or more optionally aromatic rings, optionally containing one or more heteroatoms, such as oxygen, nitrogen, sulfur and / or silicon, preferably oxygen and / or nitrogen, -R 1 represents a divalent hydrocarbon group having 5 to 15 carbon atoms, saturated or unsaturated, straight-chain or branched-chain acyclic, or containing one or more rings which may optionally be aromatic -R 3 represents a divalent straight-chain or branched alkylene group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms -X represents a divalent group selected from -NH-, -NR 7 -, or -S-, -R 7 represents a straight-chain or branched alkyl group having 1 to 20 carbon atoms and optionally containing one or more heteroatoms - f is an integer ranging from 1 to 6, preferably from 2 to 4, more preferably equal to 2 or 3.

4. The composition according to any one of claims 1 to 3, wherein the content of the moisture-crosslinkable polymer is from 10% to 60% by weight, preferably from 20% to 55% by weight, more preferably from 30% to 50% by weight, relative to the total weight of the composition.

5. The composition according to any one of claims 1 to 4, wherein the unexpanded thermally expandable organic particles comprise a thermoplastic polymer shell and a propellant embedded therein.

6. The composition according to any one of claims 1 to 5, wherein the unexpanded thermally expandable organic particles start to expand at a temperature of at least 90 °C.

7. The composition according to any one of claims 1 to 6, wherein the inorganic filler is selected from carbonated fillers.

8. A method for bonding substrates, comprising the steps of: - coating on at least one surface of a substrate the composition according to any one of claims 1 to 7, and then - bringing the substrates into contact.

9. The method for bonding substrates according to claim 8, wherein the substrates to be bonded are a battery cover and a battery container, in particular a battery cover and a battery container for a motor vehicle.

10. The method for bonding substrates according to claim 8 or 9, further comprising the step of embedding a heating element in the composition.

11. An article comprising the composition according to any one of claims 1 to 7, the composition bonding at least two substrates of the article.

12. The article according to claim 11, the article being a battery housing comprising a cover and a container, and the composition bonding the cover and the container.

13. The article according to claim 11 or 12, further comprising a heating element embedded in the composition.

14. A method for separating substrates, comprising a heating step of the article according to any one of claims 11 to 13.

15. A method for separating substrates, comprising the steps of the method for bonding substrates according to any one of claims 8 to 10, followed by a heating step.

16. Use of the composition according to any one of claims 1 to 7 as an adhesive or a sealant, preferably as a sealant.

17. Use of the composition according to any one of claims 1 to 7 for manufacturing an article comprising a heat-separable substrate.

Images