Hot melt adhesives resistant to automotive fluids

Abstract

The present invention relates to a semi-crystalline copolyamide comprising at least two units corresponding to the following formula: X / Y, wherein the X unit is a crystalline unit obtained by polycondensation of units selected from C6 to C12 α,ω-aminocarboxylic acids, C6 to C12 lactams and units (Ca diamine).(Cb diacid), wherein a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, a represents the number of carbon atoms of the diamine and is greater than 6, and b represents the number of carbon atoms of the diacid and is greater than or equal to 6, the Y unit is a unit obtained by polycondensation of units (Cd diamine).(Ce diacid), wherein d represents the number of carbon atoms of the diamine and e represents the number of carbon atoms of the diacid, d is between 4 and 48, and e is between 6 and 48, the Cd diamine is selected from aliphatic diamines, alicyclic diamines and polyethers with amine chain endcapping, the copolyamide does not contain ethylenediamine, the copolyamide comprises 30 to 98 mol% of units X and 2 to 70 mol% of units Y, according to standard ASTM D3236-88 (2009), the viscosity of the copolyamide in the molten state measured at 200° C. is 0.5 to 100 Pa.s, and the Tg of the copolyamide is lower than 0° C. The present invention also relates to a preparation method and use thereof.

Description

[0001] The present invention relates to copolyamides for encapsulating electronic devices, a process for preparing such copolyamides, compositions containing them and their use.

[0002] The use of polyamides as hot melt adhesives for encapsulating electronic devices used in the automotive sector, such as car engines, or in the medical field is known. This encapsulation needs to be carried out at low pressure to avoid damaging the part being molded.

[0003] Furthermore, this adhesive has the function of protecting the device from the environmental impacts of its environment. It may come into contact with brake fluid, engine oil, gasoline, diesel, kerosene, alcohol, battery fluid, or even coolant. These fluids are known to be highly corrosive, especially at high temperatures, and especially during engine operation. Today's automotive engines operate in increasingly enclosed environments. For efficiency and noise reasons, the air temperature surrounding the engine is increasing. Higher temperatures tend to increase the temperature of the fluids, making them more corrosive to the materials they come into contact with. These fluids are particularly susceptible to oxidation, hydrolysis, and degradation at higher temperatures. This often leads to the formation of peroxides, which decompose into free radicals, which themselves can corrode the polymer materials of automotive components that come into contact with these fluids. Therefore, improved aging resistance is essential for these fluids.

[0004] However, hot melt adhesives currently on the market have been shown to age poorly in these fluids, particularly brake fluid, engine oil, battery fluid, and gasoline and diesel fuel.

[0005] The known documents US2010 / 0282411, US2003 / 0173707, US2009 / 0291288, US2012 / 0175817, EP1533330 and EP1533331 use copolyamides with specific structures for low-pressure molding applications.

[0006] Therefore, good adhesion properties of these materials on various substrates, such as glass-filled epoxy resins, PA6, PBT, glass-filled PA6, PA6.6 or even metal surfaces, are sought. Also sought are good chemical resistance to the aforementioned liquids, in particular good resistance to thermal aging, good mechanical properties and, ultimately, satisfactory processing properties by low-pressure injection molding.

[0007] Therefore, there is a need to provide polymers that combine all of these aforementioned properties. Summary of the Invention

[0008] The present invention relates to a semicrystalline hot-melt copolyamide comprising at least two units corresponding to the following formula (1):

[0009] X / Y(1)

[0010] in

[0011] - the unit X is a crystalline unit obtained by polycondensation of units chosen from C5 to C12 α,ω-aminocarboxylic acids, C6 to C12 lactams and the units (C a diamine) and (C b diacid), a representing the number of carbon atoms of the diamine and being greater than 6, and b representing the number of carbon atoms of the diacid and being greater than or equal to 6,

[0012] - the unit Y is a unit obtained by polycondensation of the units (Cd diamine).(Ce diacid), wherein d represents the number of carbon atoms of the diamine, e represents the number of carbon atoms of the diacid, d is between 4 and 48, and e is between 6 and 48, the Cd diamine being chosen from aliphatic diamines, alicyclic diamines and polyethers having amine chain terminations,

[0013] - The copolyamide does not contain ethylenediamine,

[0014] - the copolyamide comprises 30 to 99.5 mol % of units X and 0.5 to 70 mol % of units Y,

[0015] - the copolyamide has a viscosity in the melt of 0.5 to 100 Pa·s, measured at 200° C., according to standard ASTM D3236-88 (2009),

[0016] -T of copolyamide g Below 0℃.

[0017] The invention also relates to a process for the preparation of the copolyamide according to the invention.

[0018] The invention also relates to a composition comprising the copolyamide according to the invention.

[0019] The present invention finally relates to the use of the copolyamide or a composition comprising it for encapsulating electronic devices. DETAILED DESCRIPTION

[0020] In the following description, the present invention is described in a non-limiting manner and in more detail.

[0021] Hot melt, within the meaning of the present invention, refers to the ability of the copolyamide to melt under the action of heat.

[0022] The term "semi-crystalline copolyamides" includes polyamides having a glass transition temperature T g and melting temperature T m Copolyamide. g and T f Can be determined according to ISO 11357-2:2013 and 11357-3:2013 respectively.

[0023] The nomenclature used to define polyamides is described in ISO 1874-1:1992, "Plastics - Polyamide (PA) materials for molding and extrusion - Part 1: Designations," particularly page 3 (Tables 1 and 2), and is well known to those skilled in the art. In the PAL notation, PA stands for polyamide, and L represents the number of carbon atoms in the amino acid or lactam. Thus, a polyamide is obtained by polycondensation of an amino acid or lactam containing L carbon atoms. In the PAMN notation, M represents the number of carbon atoms in the diamine, and N represents the number of carbon atoms in the diacid.

[0024] Throughout the description, all percentages given are mole percentages unless otherwise indicated.

[0025] The expression "between ... and ..." is, within the meaning of the present invention, the endpoints included in the described range.

[0026] The semicrystalline hot-melt copolyamide comprises at least two units corresponding to the following formula (1):

[0027] X / Y (1).

[0028] Unit X

[0029] Unit X is a crystalline unit obtained by polycondensation of units selected from C5 to C12 α,ω-aminocarboxylic acids, C6 to C12 lactams and units (C a diamine) and (C b diacid), a representing the number of carbon atoms of the diamine and being greater than 6, and b representing the number of carbon atoms of the diacid and being greater than or equal to 6.

[0030] Unit X can be produced by the polycondensation of one or more C5 to C12 α,ω-aminocarboxylic acids. Preferably, the α,ω-aminocarboxylic acids are selected from 7-aminoheptanoic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid.

[0031] Unit X may be produced by the polycondensation of one or more C6 to C12 lactams. Preferably, the lactam is selected from caprolactam, enantholactam and laurolactam.

[0032] The unit X may be obtained by polycondensation of a unit (C a diamine).(C b diacid), a representing the number of carbon atoms of the diamine and being greater than 6, b representing the number of carbon atoms of the diacid and being greater than or equal to 6. Preferably, a is between 7 and 48, in particular between 8 and 48, and very preferably between 9 and 48, and b is between 6 and 48, in particular between 8 and 48.

[0033] The Ca diamine may be chosen from aliphatic diamines, linear or branched, alicyclic diamines and alkyl aromatic diamines.

[0034] When the Ca diamine is aliphatic and linear, it has the formula H2N-(CH2) a-NH2, which is preferably selected from heptanediamine (a=7), octanediamine (a=8), nonanediamine (a=9), decanediamine (a=10), undecanediamine (a=11), dodecanediamine (a=12), tridecanediamine (a=13), tetradecanediamine (a=14), hexadecanediamine (a=16), octadecanediamine (a=18), octadecanediamine (a=18), eicosanediamine (a=20), and docosanediamine (a=22).

[0035] The Ca diamine may also be derived from the amination of polymerized fatty acids, as defined below. The Ca diamine may be a C36 diamine.

[0036] When the Ca diamine is aliphatic and branched, it may contain one or more methyl or ethyl substituents on the main chain. For example, it may be advantageously selected from 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine, 2-methyl-1,8-octanediamine.

[0037] When the Ca diamine is an alkyl aromatic hydrocarbon, it may be selected from 1,3-phenylenediamine and 1,4-phenylenediamine.

[0038] The Cb diacid may be selected from aliphatic diacids, linear or branched, alicyclic diacids, aromatic diacids.

[0039] Throughout the description, "diacid" or "carboxylic diacid" or "dicarboxylic acid" refers to the same product.

[0040] When the Cb diacid is aliphatic, it can be selected from adipic acid (b=6), pimelic acid (b=7), suberic acid (b=8), azelaic acid (b=9), sebacic acid (b=10), undecanedioic acid (b=11), dodecanedioic acid (b=12), brassylic acid (b=13), tetradecanedioic acid (b=14), hexadecanedioic acid (b=16), octadecanedioic acid (b=18), octadecenedioic acid (b=18), eicosanedioic acid (b=20), docosanedioic acid (b=22) and dimers of fatty acids.

[0041] When the diacid is alicyclic, it may contain the following carbon skeletons: norbornyl, cyclohexyl, dicyclohexyl, dicyclohexylpropane.

[0042] When the diacid is aromatic, it is selected from terephthalic acid (denoted by T), isophthalic acid (denoted by I) and naphthalene dicarboxylic acid.

[0043] Preferably, the unit X is selected from caprolactam, enantholactam and laurolactam, 7-aminoheptanoic acid, 11-aminoundecanoic acid and 12-aminododecanoic acid, PA1010, PA1012, PA1014, PA1018, PA1210, PA1212, PA1214, PA1218. More particularly, the unit X is selected from caprolactam, 11-aminoundecanoic acid, laurolactam, PA 1012 and PA1010.

[0044] Unit Y

[0045] Unit Y is a unit obtained by condensation of units (Cd diamine) and (Ce diacid), d represents the number of carbon atoms of the diamine, e represents the number of carbon atoms of the diacid, d is between 4 and 48, e is between 6 and 48, and Cd diamine is selected from aliphatic diamines, alicyclic diamines and amine chain-terminated polyethers.

[0046] The Cd diamine may be aliphatic and linear. It is then selected from butanediamine (d=4), pentamethylenediamine (d=5), hexamethylenediamine (d=6), heptamethylenediamine (d=7), octanediamine (d=8), nonanediamine (d=9), decanediamine (d=10), undecanediamine (d=11), dodecanediamine (d=12), tridecanediamine (d=13), tetradecanediamine (d=14), hexadecanediamine (d=16), octadecanediamine (d=18), octadecenediamine (d=18), eicosanediamine (d=20), and docosanediamine (d=22).

[0047] The Cd diamine may also be derived from the amination of polymerized fatty acids, as defined below. The Cd diamine may be a C36 diamine.

[0048] The Cd diamine may be alicyclic. It may be selected from bis(3,5-dialkyl-4-aminocyclohexyl)methane, bis(3,5-dialkyl-4-aminocyclohexyl)ethane, bis(3,5-dialkyl-4-aminocyclohexyl)propane, bis(3,5-dialkyl-4-aminocyclohexyl)butane, bis-(3-methyl-4-aminocyclohexyl)-methane (BMACM or MACM), p-bis(aminocyclohexyl)-methane (PACM) and isopropylidenebis(cyclohexylamine) (PACP), isophorone diamine (d=10), piperazine (d=4) hereinafter referred to as pip, aminoethylpiperazine. It may also contain the following carbon skeleton: norbornylmethane, cyclohexylmethane, dicyclohexylpropane, di(methylcyclohexyl), di(methylcyclohexyl)propane. A non-exhaustive list of these cycloaliphatic diamines is given in the document “Cycloaliphatic Amines” (Encyclopedia of Chemical Technology, Kirk-Othmer, 4th edition (1992), pages 386-405).

[0049] The Cd diamine can also be a polyetheramine, i.e., a polyoxyalkylene diamine. Preferably, it is a polyoxyalkylene chain with an amino group at the end of the chain. The polyoxyalkylene chain preferably contains groups of ethylene oxide (POE), propylene oxide (POP), or tetramethylene oxide (POTM), either alone or in combination. When these groups are mixed, mixtures of POE and POP or even POTM and POP are preferred.

[0050] These compounds can be obtained by cyanoacetylation of aliphatic α,ω-dihydroxypolyoxyalkylenes (known as polyether diols). The polyether amines are preferably selected from commercially available products, in particular those manufactured by Huntsman under the trade name and Selling under a brand (e.g. D400, D2000, ED 2003, XTJ 542, RT 1000, RP405, RP 2009) or by BASF Selling under a brand (e.g. EC 302, EC301; EC 303, EC 311).

[0051] Preferably, the number average molecular weight of the polyetheramine is between 60 and 2000 g.mol -1 between 80 and 1500 g.mol -1 and even more preferably between 100 and 500 g.mol -1 between.

[0052] Preferably, unit Y comprises a polyetheramine.

[0053] Ce diacids can be selected from aliphatic diacids, linear or branched, alicyclic diacids.

[0054] When the Ce diacid is aliphatic, it can be selected from adipic acid (e=6), pimelic acid (e=7), suberic acid (e=8), azelaic acid (e=9), sebacic acid (e=10), undecanedioic acid (e=11), dodecanedioic acid (e=12), brassic acid (e=13), tetradecanedioic acid (e=14), hexadecanedioic acid (e=16), octadecanedioic acid (e=18), octadecenedioic acid (e=18), eicosanedioic acid (e=20), docosanedioic acid (e=22) and dimers of fatty acids.

[0055] Polymeric fatty acids are compounds resulting from coupling reactions of unsaturated fatty acids, these reactions leading to mixtures of products with two acid functional groups (called acid dimers) or three acid functional groups (called acid trimers). Polymeric fatty acids are commercially available, in particular those sold by the company Croda under the trade name and products sold by Cognis under the trade name Products sold by Kraton Corporation under the trade name Products sold by Oleon under the trade name products.

[0056] After separation, mainly 75% to more than 98% of fatty acid dimers are obtained, in particular in mixture with monomers, 1.5-mers and the corresponding trimers. Therefore, depending on the purity of the commercial product used, the final copolyamide may contain in its structure very small amounts of polycondensation products of units X, Cd diamine and monomers or trimers of Ce diacids present in the dimer mixture.

[0057] The fatty acid dimer can then be converted to an amino dimer (by converting both acid functional groups to amine functional groups) or to an amino acid dimer (by converting one of the acid functional groups to an amine functional group).

[0058] Preferably, the diacid used for unit Y is an acid dimer, more particularly a dimer of C36 and C44 is used.

[0059] When the Ce diacid is alicyclic, it may contain the following carbon skeletons: norbornyl, cyclohexyl, dicyclohexyl, dicyclohexylpropane.

[0060] Preferably, unit Y is selected from PA pip36, PA pip44, PAPOP 40036, PA POP4006, PA POP40044, PA POP 200036, PA POP20006, PA POP200044. POP400 means the number average molecular weight is 400 g.mol -1 of polyoxypropylene diamine.

[0061] When the Ce diacid is alicyclic, it may contain the following carbon skeletons: norbornyl, cyclohexyl, dicyclohexyl, dicyclohexylpropane.

[0062] Preferably, the unit Y comprises as Ce diacid a diacid containing more than 9 carbon atoms.

[0063] According to a preferred embodiment, the unit Y comprises a polyetheramine or piperazine and a diacid containing more than 9 carbon atoms as Ce diacid.

[0064] According to a preferred embodiment, the units X are selected from 11-aminoundecanoic acid, caprolactam, laurolactam, PA1010, PA 1012 and PA 1014 and the units Y comprise polyetheramine and / or piperazine as Cd diamine and a diacid having more than 6 carbon atoms as Ce diacid.

[0065] The molar mass of the units Y is preferably in the range from 200 to 3000 g / mol, in particular from 250 to 2500 g / mol, more preferably from 300 to 2250 g / mol and very particularly from 330 to 1000 g / mol.

[0066] According to the invention, the copolyamide does not contain ethylenediamine. In fact, the inventors have observed that the presence of ethylenediamine reduces the chemical resistance of the material. This diamine appears to be involved in the expansion of the material in hot, corrosive liquids.

[0067] The copolyamide of the present invention preferably comprises fatty acid dimers in an amount of 1 to 35 mol %, in particular 2 to 30 mol %, most in particular 7 to 25 mol %.

[0068] Furthermore, the copolyamide of the present invention preferably comprises polyetherdiamine in an amount of 0.5 to 25 mol %, in particular 1 to 22 mol %, most particularly 1.5 to 14 mol %, relative to the total moles of the copolyamide constituents.

[0069] The copolyamide may also contain piperazine in an amount of 0 to 30 mol %, in particular 0 to 22 mol %, relative to the total molar number of the copolyamide constituents.

[0070] Advantageously, the copolyamide according to the invention is derived exclusively from monomers comprising acid, amine or alcohol functional groups. Furthermore, the copolyamide advantageously comprises mainly carboxylic acid chain ends.

[0071] The copolyamide according to the invention comprises 30 to 99.5 mol % of units X and 0.5 to 70 mol % of units Y, preferably 35 to 95 mol % of units X and 5 to 65 mol % of units Y, more particularly 40 to 90 mol % of units X and 10 to 60 mol % of units Y.

[0072] The molar percentages of units X, Y and optionally Z are calculated by calculating the percentages of the number of moles of the monomer constituting the unit X, for example relative to the sum of the number of moles of all monomers constituting the copolyamide, i.e. X, Y and optionally Z, when present, and excluding chain limiters: excess diamine or diacid is not taken into account. The following formula illustrates the calculation process:

[0073] [Formula 1]

[0074]

[0075] The copolyamide according to the present invention has a viscosity in the melt of 0.5 to 100 Pa.s, preferably 0.5 to 70 Pa.s, more preferably 1 to 50 Pa.s at 200° C., and more particularly 2 to 30 Pa.s at 200° C., measured according to ASTM D3236-88 (2009). More specifically, the viscosity in the melt is measured at 200° C. using a Brookfield rheometer using an SC 4-27 module according to ASTM D3236-88 (2009).

[0076] The copolyamides according to the invention have a temperature Tg below 0° C. The glass transition temperature Tg indicated above was determined by differential scanning calorimetry (DSC) according to ISO 11357-2:2013, Plastics - Differential Scanning Calorimetry (DSC), Part 2. The heating and cooling rates were 20° C. / min.

[0077] Advantageously, the copolyamide of the invention has a tensile modulus at 23° C., measured according to ISO 527 standard, ranging from 5 to 240 MPa, preferably from 10 to 223 MPa, more preferably from 30 to 220 MPa and most particularly from 65 to 200 MPa.

[0078] Preferably, the copolyamide of the invention has a threshold stress at 23° C., measured according to standard ISO 527, ranging from 4 to 12 MPa, preferably from 5 to 11.5 MPa and more particularly from 6 to 11 MPa.

[0079] The melting temperature of the copolyamide of the invention is preferably in the range of 80 to 220° C., in particular 90 to 210° C., measured by differential scanning calorimetry (DSC) according to standard NF EN ISO 11 357-3, using a heating rate of 20° C. / min.

[0080] According to one embodiment of the invention, the copolyamide comprises only two units X and Y as defined above.

[0081] According to another embodiment, the semi-crystalline hot-melt copolyamide according to the present invention may contain an additional unit. The copolyamide according to the present invention can be represented by the following formula (2):

[0082] X / Y / Z(2)

[0083] in

[0084] - Unit X is as defined previously,

[0085] - Unit Y is as defined above,

[0086] - the unit Z is a unit obtained by polycondensation of the units (Cf diamine).(Cg diacid), wherein f represents the number of carbon atoms of the diamine, g represents the number of carbon atoms of the diacid, f is between 4 and 48 and g is between 4 and 48, Cf diamine being chosen from aliphatic diamines and alicyclic diamines,

[0087] - the copolyamide does not contain ethylenediamine,

[0088] - the copolyamide comprises 30 to 99.5 mol % of units X and 0.5 to 70 mol % of units Y and units Z,

[0089] - The copolyamide has a melt viscosity of between 0.5 and 100 Pa.s measured at 200°C according to standard ASTM D3236-88 (effective in 2009),

[0090] - The Tg of the copolyamide is below 0°C.

[0091] In other words, the copolyamide according to the invention comprises at least three units: the X, Y and Z units.

[0092] Cf diamine represents a diamine as defined above for Cd diamine. Cg diacid represents a diacid as defined above for Ce diacid.

[0093] Preferably, the copolyamide according to the invention comprises at least one unit selected from PA pip.36, PA pip44, PAPOP 40036, PA POP4006, PA POP40044, PA POP 200036, PA POP2000.6, PA POP200044.

[0094] Preferably, the unit Z comprises as Cg diacid a diacid containing more than 5 carbon atoms.

[0095] According to one preferred embodiment, the unit Z comprises a polyetheramine or piperazine as Cf diamine and a diacid comprising more than 5 carbon atoms as Cg diacid.

[0096] Particularly preferably, the copolyamide according to the invention comprises units X selected from amino acids and lactams, units Y comprising a polyetheramine as Cd diamine and a diacid comprising at least 6 carbon atoms as Ce diacid, and units Z comprising piperazine as Cf diamine and a diacid comprising at least 6 carbon atoms as Cg diacid.

[0097] According to another preferred embodiment, the Ce diacid and the Cg diacid are C36 acid dimers.

[0098] According to a preferred embodiment, the Cd diamine is a polyetheramine, the Cf diamine is piperazine, and the Ce diacid and the Cg diacid are C36 acid dimers.

[0099] In a particularly preferred manner, the copolyamide according to the invention comprises units X selected from amino acids and lactams, units Y comprising a polyetheramine as Cd diamine and a diacid comprising 36 carbon atoms as Ce diacid, and units Z comprising piperazine as Cf diamine and a diacid comprising 36 carbon atoms as Cg diacid.

[0100] The copolyamide according to the invention comprises 30 to 99 mol % of units X, 0.5 to 69.5 mol % of units Y and 0.5 to 69.5 mol % of units Z; preferably 50 to 97 mol % of units X, 1.5 to 48.5 mol % of units Y and 1.5 to 48.5 mol % of units Z.

[0101] According to another preferred embodiment, the copolyamide according to the invention does not contain amines having fewer than 7 carbon atoms, with the exception of piperazine.

[0102] Preferably, the copolyamide according to the present invention comprises at least one unit selected from PA6, PA11, PA1010, PA1012, PA 12, PA pip36, PA pip44, PA POP40036, PA POP40010, PA POP4006 and mixtures thereof.

[0103] Preferably, the copolyamide according to the present invention is selected from the following structures: PA6 / pip36, PA 11 / pip36, PA12 / pip36, PA1010 / pip36, PA1012 / pip36, PA6 / POP40036, PA11 / POP40036, PA12 / POP40036, PA1010 / POP40036, PA 1012 / POP40036, 6 / POP4006, PA 11 / POP4006, PA12 / POP4006, PA1010 / POP4006, PA 1012 / POP4006, PA 6 / POP40010, PA 11 / POP40010, PA 12 / POP40010, PA 1010 / POP40010, PA 1012 / POP40010, PA 6 / pip36 / POP40036, PA 11 / pip36 / POP40036, PA 12 / pip36 / POP40036, PA 1010 / pip36 / POP40036, PA 1012 / pip36 / POP40036, PA 6 / POP40010 / pip10, PA 11 / POP40010 / pip10, PA12 / POP40010 / pip10, PA 1010 / POP40010 / pip10, PA1012 / POP40012 / pip12. Even more preferably, the copolyamide according to the invention is chosen from PA11 / POP40036 / pip36, PA6 / POP40036 / pip36, PA11 / POP200036 / pip36 and PA6 / POP200036 / pip36.

[0104] According to one embodiment of the invention, the copolyamide comprises only the three units X, Y and Z defined above. According to this embodiment, the copolyamide consists of one or more different units X, one or more different units Y and one or more different units Z.

[0105] Chain limiting agent:

[0106] The copolyamides of the invention are synthesized in a conventional manner, if necessary in the presence of chain limiters or chain terminators.

[0107] Suitable chain terminators for reacting with the amine terminal functional groups may be monocarboxylic acids, anhydrides, such as phthalic anhydride, monohalogen acids, monoesters or monoisocyanates.

[0108] Monocarboxylic acids are preferably used. They can be selected from aliphatic monocarboxylic acids, such as acetic acid, propionic acid, lactic acid, valeric acid, caproic acid, capric acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyric acid; alicyclic acids, such as cyclohexanecarboxylic acid; aromatic monocarboxylic acids, such as benzoic acid, toluic acid, α-naphthoic acid, β-naphthoic acid, methylnaphthoic acid, phenylacetic acid, and the like, and mixtures thereof. Preferred compounds are fatty acids, in particular acetic acid, propionic acid, lactic acid, valeric acid, caproic acid, capric acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, and stearic acid.

[0109] Among the chain terminators suitable for reacting with the acid terminal functional groups, mention may be made of monoamines, monoalcohols, monoisocyanates.

[0110] Monoamines are preferably used. They can be selected from aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, laurylamine, stearylamine, dimethylamine, diethylamine, dipropylamine and dibutylamine; alicyclic amines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine, naphthylamine, etc.; and mixtures thereof.

[0111] Preferred compounds are butylamine, hexylamine, octylamine, decylamine, laurylamine, stearylamine, cyclohexylamine and aniline.

[0112] The chain limiter may also be a dicarboxylic acid, introduced in a stoichiometric excess relative to the diamine(s), or a diamine, introduced in a stoichiometric excess relative to the diacid(s).

[0113] Preparation method:

[0114] The present invention also relates to a process for preparing the copolyamide according to the invention. In a suitable reactor equipped with a mixer, all the reagents are charged and then heated under nitrogen at a temperature of 190 to 250° C. for 20 to 180 minutes (until the volume of the distillate no longer increases under nitrogen purge). The reactor is then placed under vacuum at a pressure of 0.5 to 300 mBar and maintained under these conditions until the desired viscosity is achieved.

[0115] Composition:

[0116] According to another aspect, the present invention relates to a composition comprising a copolyamide as defined above.

[0117] Advantageously, the composition defined above further comprises additives chosen from antioxidants, UV stabilizers, heat stabilizers, plasticizers, nucleating agents, tackifiers, impact modifiers, flame retardants, antistatic agents, reinforcing agents, lubricants, organic and inorganic fillers, optical brighteners, release agents, pigments, colorants, catalysts and mixtures thereof.

[0118] Preferably the composition comprises only compounds having acid, amine or alcohol functionality. Particularly preferably the composition does not comprise isocyanate or urethane compounds.

[0119] Advantageously, the composition of the invention does not comprise alkaline catalysts. In fact, this type of catalyst may affect the chemical resistance.

[0120] The composition according to the invention can be used to produce molded parts that can be produced by known methods, such as extrusion, cast molding, injection molding, compression molding, transfer molding, etc. However, according to the present invention, the composition is molded into molded parts by low-pressure injection molding. The injection molding cycle can include the following different steps:

[0121] a) After the parts to be bonded are inserted, close the mold.

[0122] b) injecting the molten composition according to the invention into the mold until the pressure is between 0.5 and 50 bars and optionally subjecting it to a holding pressure,

[0123] c) allowing the molded composition to cool and solidify,

[0124] d) The mold opens,

[0125] e) Remove the injection molded part from the mold.

[0126] Low-pressure injection molding processes typically operate in the range of 2 to 40 bars and temperatures between 160 and 250°C.

[0127] The composition according to the invention can therefore be injection moulded at low pressure, that is to say at a pressure of less than 100 bar, preferably less than 50 bar.

[0128] use:

[0129] According to another aspect, the invention relates to the use of the copolyamide as defined above in the encapsulation, also called overmolding or molding, of electronic devices, preferably under the hood of a vehicle or in a medical device.

[0130] The invention also relates to the use of at least one copolyamide as described above for producing a hot-melt adhesive, in particular a yarn, film, granulate, filament, mesh, powder or suspension.

[0131] The invention finally relates to the use of semicrystalline copolyamides comprising at least two units corresponding to the following formula (3):

[0132] X / Y(3)

[0133] in

[0134] - unit X is a crystalline unit obtained by polycondensation of units selected from C5 to C12 α, ω-aminocarboxylic acids, C6 to C12 lactams and units (Ca diamine) . (Cb diacid) , where a represents the number of carbon atoms of the diamine and b represents the number of carbon atoms of the diacid, and a and b are greater than or equal to 4,

[0135] - Unit Y is a unit obtained by polycondensation of units (Cd diamine).(Ce diacid), wherein d represents the number of carbon atoms of the diamine, e represents the number of carbon atoms of the diacid, d is between 4 and 48, e is between 6 and 48, and Cd diamine is selected from aliphatic diamines, alicyclic diamines and amine chain-terminated polyethers,

[0136] - The copolyamide does not contain ethylenediamine,

[0137] - the copolyamide comprises 30 to 99.5 mol % of units X and 0.5 to 70 mol % of units Y,

[0138] - The viscosity of the copolyamide in the melt measured at 200°C is between 0.5 and 70 Pa.s according to standard ASTM D3236-88 (effective in 2009),

[0139] - Tg of the copolyamide is below 0°C,

[0140] Hot melt adhesives used to produce materials with improved chemical resistance to automotive fluids after heat aging.

[0141] It has been shown that copolyamides with formula (3) have good adhesion properties on various substrates, such as glass-filled epoxy resins, PA6, PBT, glass-filled PA6, PA6.6 and even metal surfaces, good mechanical properties, satisfactory low-pressure injection molding processability and, most importantly, improved chemical resistance to automotive fluids after thermal aging of the material.

[0142] Automotive fluids within the meaning of the present invention are brake fluid, engine oil, gasoline, for example diesel, biodiesel, battery fluid, coolant.

[0143] For improved chemical resistance after thermal aging of the material, the expansion is less than 20 wt%.

[0144] Preferably, the units X, Y and optionally Z, and the other characteristics of the copolyamide are as defined above.

[0145] The invention is illustrated by the accompanying drawings and the following non-limiting examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0146] [ Figure 1] represents the curves obtained after tensile tests carried out on dumbbell-shaped specimens of the copolyamide according to the present invention and the comparative material. The abscissa represents the deformation in percentage and the ordinate represents the stress in MPa.

[0147] Example:

[0148] 1. Preparation of copolyamide:

[0149] The synthesis is carried out as follows. In a suitable reactor equipped with a mixer, all reagents are loaded and then heated at 235°C for 90 minutes under nitrogen. The reactor is then placed under a vacuum of 100 mBar and maintained under these conditions until the desired viscosity is achieved.

[0150] The following copolyamides were prepared from the reagents listed in Table 1 below.

[0151] [Table 1]

[0152]

[0153] In this table:

[0154] 11-amino acid means 11-aminoundecanoic acid.

[0155] DA10 represents decanediamine.

[0156] DC 10 represents sebacic acid.

[0157] EC 302 is sold by BASF and has a molecular weight of 400 g.mol -1 of polyoxypropylene diamine.

[0158] 1013 is sold by Croda and is referred to as a C36 acid dimer.

[0159] D 2000 is sold by Huntsman and refers to a molecular weight of 2000 g.mol -1 of polyoxypropylene diamine.

[0160] Examples A and G are comparative copolyamides and Examples B to F are copolyamides according to the invention.

[0161] In the synthesis process according to Example B of the present invention, excess sebacic acid was used as a chain limiter. In the synthesis process according to Examples C, D, E and F of the present invention, excess 1013 was used as a chain limiting agent.

[0162] The synthesized copolyamide has the following composition and properties.

[0163] The Tg is measured by differential scanning calorimetry (DSC) according to standard ISO 11357-2:2013, Plastics - Differential Scanning Calorimetry (DSC) Part 2. The heating and cooling rate is 20°C / min.

[0164] The viscosity in the molten state is measured at 200° C. with the aid of a Brookfield rheometer using an SC 4-27 module, according to standard ASTM D3236-88 (2009).

[0165] [Table 2]

[0166]

[0167] *ND = not determined.

[0168] 2. Sample preparation

[0169] The synthesized copolymer was ground. 100 cm2 of granules were prepared by pressing the obtained granules using a Darragon plate press heated to 220°C and a die. 2 The thickness of the plate is 2 mm.

[0170] Use the following scheme:

[0171] Compressed at 220℃ and 1 bar for 1 minute,

[0172] Compressed at 220℃ and 50bars for 2 minutes,

[0173] Cooling at 50 bars for 4 minutes (cold water circulated in the platens).

[0174] Dumbbell-shaped specimens The support of the component allows the cutting of dumbbell-shaped specimens 1BA These flat plates are cut (Annex A standard ISO 527-2:2012) for tensile testing according to standard ISO 527-2:2012.

[0175] 3. Sample evaluation:

[0176] 3.1. Anti-swelling:

[0177] The aging of the samples was evaluated in brake fluid. The samples were placed in DOT 5.1 brake fluid at 80°C for 24 hours. The expansion of each sample was then measured by taking the difference between the weight of the dumbbell specimen measured before and after aging. To obtain reproducible results, the aged dumbbell specimens 1BA were wiped dry to remove any residual liquid from the sample surface. The results of the expansion test are reported in Table 3 below.

[0178] [Table 3]

[0179] CoPA Expansion (%) Comparative Example A 43.9 Inventive Example B 1010 / POP400.10 12.9 Inventive Example C 11 / POP400.36 14.0 Inventive Example D 11 / POP400.36 10.0 Inventive Example E 11 / pip.36 / POP400.36 16.8 Inventive Example F 6 / pip.36 / POP400.36 14.5 Comparative Example G 11 / POP400.10 17.0

[0180] The results obtained show that the copolyamides according to the invention are more resistant to thermal aging in brake fluid than the comparative materials.

[0181] 3.2. Mechanical resistance:

[0182] According to the standard ISO 527-2:2012, the tensile test was carried out on a dumbbell-shaped specimen 1BA (Appendix A standard ISO 527-2:2012).

[0183] The results are shown above Figure 1 and in Table 2 above. These results show that the copolyamides according to the invention have better mechanical properties than the comparative materials.

[0184] Furthermore, we note that the copolyamides of comparative examples A and G have high moduli and high threshold stresses, which are undesirable for parts overmolded by low-pressure injection molding. The copolyamides containing units derived from acid dimers (Examples C to F) exhibit significantly more suitable mechanical properties and are therefore clearly more suitable for this application.

Claims

1. A semi-crystalline copolyamide comprising at least two units corresponding to the following formula: X / Y wherein - unit X is a crystalline unit obtained by polycondensation as a unit of 11-aminoundecanoic acid, - Unit Y is a unit obtained by polycondensation of units (Cd diamine).(Ce diacid), wherein d represents the number of carbon atoms of the diamine, and e represents the number of carbon atoms of the diacid, d is between 4 and 48, e is between 6 and 48, Cd diamine is selected from aliphatic diamines, alicyclic diamines and amine chain-terminated polyethers, Ce diacid is a diacid selected from acid dimers, - The copolyamide does not contain ethylenediamine, - the copolyamide comprises 30 to 99.5 mol % of units X and 0.5 to 70 mol % of units Y, - the copolyamide has a melt viscosity measured at 200° C. between 0.5 and 100 Pa.s according to standard ASTM D3236-88 (2009), - The Tg of the copolyamide is below 0°C.

2. The copolyamide according to claim 1, characterized in that Cd diamine is a polyether terminated with an amine chain.

3. The copolyamide according to claim 1 or 2, characterized in that It comprises units Y which comprise polyetheramine and / or piperazine as Cd diamine and a diacid comprising more than 6 carbon atoms as Ce diacid.

4. The copolyamide according to claim 1 or 2, characterized in that It contains an additional unit, and the copolyamide then has the following formula (2): X / Y / Z(2) in - unit X as defined in claim 1, - unit Y as defined in claim 1, - the unit Z is a unit obtained by polycondensation of the units (Cf diamine).(Cg diacid), wherein f represents the number of carbon atoms of the diamine, g represents the number of carbon atoms of the diacid, f is between 4 and 48 and g is between 4 and 48, Cf diamine being chosen from aliphatic diamines and alicyclic diamines, - The copolyamide does not contain ethylenediamine, - the copolyamide comprises 30 to 99.5 mol % of units X and 0.5 to 70 mol % of units Y and units Z, - the copolyamide has a melt viscosity measured at 200° C. between 0.5 and 100 Pa.s according to standard ASTM D3236-88 (2009), - The Tg of the copolyamide is below 0°C.

5. The copolyamide according to claim 1 or 2, characterized in that The melt viscosity is between 0.5 and 70 Pa·s at 200°C.

6. The copolyamide according to claim 5, characterized in that The melt viscosity is between 1 and 50 Pa·s at 200°C.

7. The copolyamide according to claim 5, characterized in that The melt viscosity is between 2 and 30 Pa·s at 200°C.

8. The copolyamide according to claim 1 or 2, characterized in that It comprises at least one unit selected from PA11 PApip36, PApip44 POP40036 and mixtures thereof, wherein pip represents piperazine and POP represents polyoxypropylenediamine.

9. The copolyamide according to claim 4, characterized in that It comprises units Y comprising a polyetheramine as Cd diamine and a diacid comprising more than 6 carbon atoms as Ce diacid, units Z comprising piperazine as Cf diamine and a diacid comprising more than 6 carbon atoms as Cg diacid.

10. The copolyamide according to claim 1 or 2, characterized in that It has the following formula: PA 11 / pip36, PA 11 / POP40036, PA 11 / pip36 / POP40036, wherein pip represents piperazine and POP represents polyoxypropylenediamine.

11. A composition comprising a copolyamide as defined in any one of claims 1 to 10.

12. The composition according to claim 11, characterized in that It contains additives selected from antioxidants, UV stabilizers, heat stabilizers, plasticizers, nucleating agents, tackifiers, impact modifiers, flame retardants, antistatic agents, reinforcing agents, lubricants, organic and inorganic fillers, optical brighteners, mold release agents, colorants, catalysts and mixtures thereof.

13. The composition according to claim 11, characterized in that It contains pigments as additives.

14. The composition according to any one of claims 11 to 13, characterized in that It is suitable for injection molding at pressures less than 100 bars.

15. The composition according to claim 14, characterized in that It is suitable for injection molding at pressures less than 50 bars.

16. Use of a copolyamide as defined in any one of claims 1 to 10 or a composition as defined in any one of claims 11 to 15 in the encapsulation of electronic devices.

17. The use according to claim 16, characterized in that The electronic device is located under the hood of a vehicle or in a medical device.

18. Use of a semicrystalline copolyamide comprising at least two units corresponding to the following formula: X / Y in - Unit X is a unit crystal obtained by polycondensation of units selected from 11-aminoundecanoic acid, - Unit Y is a unit obtained by polycondensation of units (Cd diamine).(Ce diacid), wherein d represents the number of carbon atoms of the diamine and e represents the number of carbon atoms of the diacid, d is between 4 and 48, e is between 6 and 48, the Cd diamine is selected from aliphatic diamines, alicyclic diamines and amine chain-terminated polyethers, and the Ce diacid is a diacid selected from acid dimers, - The copolyamide does not contain ethylenediamine, - the copolyamide comprises 30 to 99.5 mol % of units X and 0.5 to 70 mol % of units Y, - the copolyamide has a melt viscosity measured at 200° C. between 0.5 and 70 Pa.s according to standard ASTM D3236-88 (2009), - Tg of the copolyamide is below 0°C, Hot melt adhesives used to produce materials with improved chemical resistance to automotive fluids after heat aging.

19. The use according to claim 18, characterized in that Units X and Y are as claimed in any one of claims 2 to 10.

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