WO2021209729A2

WO2021209729A2 - Hot melt adhesive withstanding motor vehicle fluids

Info

Publication number: WO2021209729A2
Application number: PCT/FR2021/050679
Authority: WO
Inventors: Quentin Pineau; Thomas PRENVEILLE; Pierre-Jean ROUMANET
Original assignee: Arkema France; Bostik Sa
Priority date: 2020-04-17
Filing date: 2021-04-16
Publication date: 2021-10-21
Also published as: FR3109384B1; EP4136134A2; WO2021209729A3; CN116096783A; FR3109384A1

Abstract

The invention relates to a semi-crystalline copolyamide comprising at least two units corresponding to the following formula: X/Y where - the X unit is a crystalline unit obtained by polycondensation of a unit selected from a C6-C12 alpha,omega-aminocarboxylic acid, a C6-C12 lactam and a (Ca diamine).(Cb diacid) unit, where a is the number of carbon atoms of the diamine and is greater than 6 and b is the carbon number of the diacid and is greater than or equal to 6; - the Y unit is a unit obtained by the polycondensation of a (Cd diamine).(Ce diacid) unit, where d is the number of carbon atoms of the diamine and e is the carbon number of the diacid, d being between 4 and 48 and e being between 6 and 48, the Cd diamine being selected from aliphatic diamines, cycloaliphatic diamines and amine-terminated polyethers; - the copolyamide not comprising ethylenediamine; - the copolyamide comprising from 30 to 98 mol % of unit X and from 2 to 70 mol % of unit Y; - the copolyamide having a viscosity in the molten state, measured according to standard ASTM D3236-88 (2009), of between 0.5 and 100 Pa.s at 200° C; - the copolyamide having a Tg below 0°C. The invention also relates to a method for preparing same and to the use thereof.

Description

Title: Automotive Fluid Resistant Hot Melt Adhesive

The present invention relates to copolyamides for the encapsulation of electronic devices, a process for preparing such a copolyamide, a composition containing it and its use.

It is known to use polyamides as hot melt adhesives to encapsulate electronic devices used in the automotive fields, such as in automotive engines or in the medical field. This encapsulation needs to be carried out at low pressure, so as not to damage the part to be molded.

[0003] Furthermore, this adhesive has the function of protecting the device from the environment, in which it is placed. It can come in contact with brake fluid, engine oil, gasoline, diesel, kerosene, alcohol, battery fluid or even coolant. These fluids are known to be very aggressive, especially when brought to high temperatures, especially during engine operation. Today's car engines find themselves in an increasingly confined environment. The temperature of the air surrounding the engine is rising for reasons of efficiency and noise. The higher temperature will tend to increase the temperature of the liquids, making the latter even more aggressive towards the materials in contact with them. These liquids, under the effect of higher temperatures, are particularly sensitive to oxidation, hydrolysis and degradation. This typically results in the formation of peroxides, which decompose into free radicals, which themselves attack the polymeric material of the automotive part in contact with said liquid. The resistance to aging in the face of these liquids must therefore be improved.

However, it turns out that the hot-melt adhesives currently marketed age poorly in these liquids, and more particularly in brake fluid, engine oil, battery fluid and diesel gasoline.

It is known from documents US2010 / 0282411,

US2003 / 0173707, US2009 / 0291288, US2012 / 0175817, EP1533330 and EP1533331 to use specially structured copolyamides for low pressure molding applications.

[0006] Thus, good adhesion properties of these materials are sought for on various substrates, such as epoxy resins loaded with glass fibers, PA6, PBT, PA6 loaded with glass fibers, PA6.6 or still on metal surfaces. Good chemical resistance to the above-mentioned liquids is also sought, and in particular good resistance to hot aging, good mechanical properties, and finally satisfactory processability for injection at low pressure.

[0007] There is therefore a real need to provide polymers combining all of these aforementioned properties.

Summary of the invention

The invention relates to a semi-crystalline hot-melt copolyamide comprising at least two units corresponding to the following formula (1):

X / Y (1) where

the X unit is a crystalline unit obtained by the polycondensation of a unit chosen from a C5 to C12 alpha, omega-aminocarboxylic acid, a C6 to C12 lactam and a unit (Ca diamine). (Cb diacid), with a representing the number of carbon atoms of the diamine and being greater than 6 and b representing the carbon number of the diacid and being greater than or equal to 6,

the Y unit is a unit obtained by the polycondensation of one unit (Cd diamine). (diacid in Ce), with d representing the number of carbon atoms of the diamine and e representing the number of carbon of the diacid, d being between 4 and 48 and e being between 6 and 48, the Cd diamine being chosen by aliphatic diamines, cycloaliphatic diamines and polyethers terminating amine chains,

-the copolyamide not containing ethylene diamine,

the copolyamide comprising from 30 to 99.5% by mole of unit X and from 0.5 to 70% by mole of unit Y,

- copolyamide having a viscosity in the molten state measured according to standard ASTM D3236-88 (2009) of between 0.5 and 100 Pa.s at 200 ° C,

-the copolyamide having a Tg of less than 0 ° C.

[0009] The invention also relates to a process for preparing the copolyamide according to the invention.

[0010] A subject of the invention is also a composition comprising the copolyamide according to the invention.

Finally, the invention relates to the use of this copolyamide or of the composition containing it to encapsulate electronic devices.

detailed description

[0012] The invention is now described in more detail and in a non-limiting manner in the description which follows.

[0013] For the purposes of the present invention, the term “hot melt” means the ability of the copolyamide to melt under the effect of heat.

The expression "semi-crystalline copolyamide" covers copolyamides which have both a glass transition temperature Tg and a melting temperature Tm. Tg and Tf can be determined according to ISO 11357-2: 2013 and 11357-3: 2013 respectively.

The nomenclature used to define the polyamides is described in the ISO 1874-1: 1992 standard "Plastics - Polyamide materials (PA) for molding and extrusion - Part 1: Designation", in particular on page 3 (tables 1 and 2) and is well known to those skilled in the art. In the PAL notation, PA denotes polyamide and L denotes the number of carbon atoms of the amino acid or else of the lactam. Thus, polyamide is obtained by the polycondensation of the amino acid or of the lactam comprising L carbon atoms. In the PAMN notation, M denotes the number of carbon atoms of the diamine and N denotes the number of carbon atoms of the diacid.

Throughout the description, unless otherwise indicated, all the percentages indicated are molar percentages.

By the expression "between ... and .." is meant within the meaning of the present invention that the terminals are included in the range described.

The semi-crystalline hot-melt copolyamide comprising at least two units corresponding to the following formula (1): X / Y (1).

The pattern X

The X unit is a crystal unit obtained by the polycondensation of a unit chosen from a C5 to C12 alpha, omega-aminocarboxylic acid, a C6 to C12 lactam and a unit (Ca diamine). (Cb diacid), with a representing the number of carbon atoms of the diamine and being greater than 6 and b representing the carbon number of the diacid and being greater than or equal to 6.

[0020] The X unit can result from the polycondensation of one or more C5 to C12 alpha, omega-aminocarboxylic acids. Preferably, the alpha, omega-aminocarboxylic acid is selected from among 7-amino-heptanoic acid, 11-amino-undecanoic acid and 12-amino-dodecanoic acid.

[0021] The X unit can result from the polycondensation of one or more C6 to C12 lactams. Preferably, the lactam is chosen from caprolactam, enantholactam and lauryllactam.

The X unit can result from the polycondensation of a unit (diamine in Ca). (Cb diacid), with a representing the number of carbon atoms of the diamine and being greater than 6 and b representing the carbon number of the diacid and being greater than or equal to 6.

Preferably, a is between 7 and 48, more particularly between 8 and 48, and very preferably between 9 and 48 and b is between 6 and 48, more particularly between 8 and 48.

The Ca diamine can be chosen from aliphatic, linear or branched diamines, cycloaliphatic diamines and alkylaromatic diamines.

When the Ca diamine is aliphatic and linear, of formula H2N- (CH2) a-NH2, it is preferably chosen 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), docosanediamine (a = 22).

[0025] The Ca diamine can also come from the amination of polymerized fatty acids, as defined below. The Ca diamine can be a C36 diamine.

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 can advantageously be chosen 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.

When the Ca diamine is alkylaromatic, it can be chosen from 1, 3-xylylenediamine and 1, 4-xylylenediamine.

The Cb diacid can be chosen from aliphatic, linear or branched diacids, cycloaliphatic diacids, aromatic diacids.

Throughout the description, the expressions "diacid" or "dicarboxylic acid" or "dicarboxylic acid" denote the same product.

When the Cb diacid is aliphatic, it can be chosen from adipic acid (b = 6), heptanedioic acid (b = 7), acid octanedioic 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 (b = 20), docosanedioic acid (b = 22) and fatty acid dimers.

When the diacid is cycloaliphatic, it may contain the following carbon skeletons: norbornyl, cyclohexyl, dicyclohexyl, dicyclohexylpropane.

When the diacid is aromatic, it is chosen from terephthalic acid (denoted T), isophthalic (denoted I) and naphthalenic diacids.

Preferably, the unit X is chosen from caprolactam, oenantholactam and lauryllactam, 7-amino-heptanoic acid, 11-amino-undecanoic acid and 12-amino-dodecanoic acid, PA1010, PA1012, PA1014, PA1018, PA1210, PA1212, PA1214, PA1218. More particularly, the unit X is chosen from caprolactam, 11-amino-undecanoic acid, lauryllactam, PA 1012 and PA 1010.

The Y pattern

The Y unit is a unit obtained by the polycondensation of one unit (Cd diamine). (Ce diacid), with d representing the number of carbon atoms of the diamine and e representing the carbon number of the diacid, d being between 4 and 48 and e being between 6 and 48, the Cd diamine being selected from aliphatic diamines, cycloaliphatic diamines and polyethers terminating amine chains.

The Cd diamine can be aliphatic and linear. It is then chosen from butanediamine (d = 4), pentanediamine (d = 5), hexanediamine (d = 6), heptanediamine (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), docosanediamine (d = 22).

[0036] The Cd diamine can also come from the amination of polymerized fatty acids, as defined below. The Cd diamine can be a C36 diamine.

The Cd diamine can be cycloaliphatic. It can be chosen from bis (3,5-dialkyl-4-aminocyclohexyl) methane, bis (3,5-dialkyl-4-aminocyclohexyl) ethane, bis (3,5-dialkyl-4-aminocydohexyl) propane, bis (3,5-dialkyl-4-aminocyclo-hexyl) butane, bis- (3- methyl-4-aminocyclohexyl) -methane (BMACM or MACM), p- bis (aminocyclohexyl) - methane (PACM) ) and isopropylidenedi (cyclohexylamine) (PACP), isophoronediamine (d = 10), piperazine (d = 4) noted pip below, amino-ethylpiperazine. It can also include the following carbon skeletons: norbornyl methane, cyclohexylmethane, dicyclohexylpropane, di (methylcyclohexyl), di (methylcyclohexyl) propane. A non-exhaustive list of these cycloaliphatic diamines is given in the publication "Cycloaliphatic Amines" (Encyclopaedia of Chemical Technology, Kirk-Othmer, 4th Edition (1992), pp. 386-405).

[0038] The Cd diamine can also be a polyetheramine, ie a polyoxyalkylene diamine. Preferably, it is a polyoxyalkylene chain carrying an amine group at the end of the chain. The polyoxyalkylene chain preferably contains oxyethylene (POE), oxypropylene (POP), oxytetramethylene (POTM) groups, alone or as a mixture. When the groups are mixed, the POE and POP or alternatively POTM and POP mixtures are preferred.

These compounds can be obtained by cyanoacetylation of aliphatic α, w-dihydroxylated polyoxyalkylene called polyetherdiols. The polyetheramine is preferably chosen from commercially available products, in particular sold by Huntsman under the brands Jeffamine® and Elastamine® (for example Jeffamine® D400, D2000, ED 2003, XTJ 542, Elastamine® RT 1000, RP 405, RP 2009) or under Baxxodur® brand by the company BASF (for example Baxxodur® EC 302, EC 301; EC 303, EC 311).

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

Preferably, the Y unit comprises a polyetheramine.

The Ce diacid can be chosen from aliphatic, linear or branched diacids, cycloaliphatic diacids.

When the Ce diacid is aliphatic, it can be chosen from adipic acid (e = 6), heptanedioic acid (e = 7), octanedioic acid (e = 8), azelaic acid (e = 9), sebacic acid (e = 10), undecanedioic acid (e = 11), dodecanedioic acid (e = 12), brassylic 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 fatty acid dimers.

Polymerized fatty acids denote the compounds produced from coupling reactions of unsaturated fatty acids which lead to mixtures of products carrying two acid functions (called acid dimers) or three acid functions (called acid trimers). Polymerized fatty acids are marketed and in particular the product of the trade name Pripol ^® marketed by the company Croda can be used as well as the product of the trade name Empol ^® marketed by the company Cognis or the product of the trade name Unydime ^® marketed by the company Kraton. or the trade name product Radiacid ^® marketed by the company Oleon.

After separation, the fatty acid dimers are obtained predominantly from 75% to more than 98%, as a mixture with in particular the monomer, the 1 1/2 mer and the corresponding trimer. Thus, depending on the purity of the commercial product used, the final copolyamide may comprise in its structure, in a very minor amount, of the polycondensation products of the X unit, of the Cd diamine and of the monomers or trimers of the Ce diacid present in the mixture of the dimer.

The fatty acid dimers can then be transformed into amine dimers (by transformation of the two acid functions into an amine function) or into amino acid dimers (by transformation of one of the acid functions into an amine function).

Preferably, the diacids used for the Y unit are acidic dimers, and more particularly the C36 and C44 dimers are used.

When the C-diacid is cycloaliphatic, it may contain the following carbon skeletons: norbornyl, cyclohexyl, dicyclohexyl, dicyclohexylpropane.

Preferably, the Y unit is chosen from PA pip36, PA pip44, PA POP 40036, PA POP4006, PA POP40044, PA POP 200036, PA POP20006, PA POP200044. POP400 signifying a polyoxypropylenediamine unit with a number average molecular mass of 400 g. mol ¹ .

Preferably, the unit Y comprises a diacid comprising more than 9 carbon atoms as a C-diacid.

According to a preferred embodiment, the unit Y comprises a polyetheramine or piperazine and a diacid comprising more than 9 carbon atoms as a C-diacid.

According to a preferred embodiment, an X unit chosen from 11-amino-undecanoic acid, caprolactam, lauryllactam, PA 1010, and PA 1012 and PA 1014 and a Y unit comprising a polyetheramine and / or piperazine as Cd diamine and a diacid having more than 6 carbon atoms as Cdiacid. The molar mass of the Y unit 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 g / mol to 1000 g / mol.

The copolyamide according to the invention does not contain ethylene diamine. Indeed, the inventors have observed that the presence of ethylenediamine deteriorates the chemical resistance properties of the material. It seems that this diamine participates in the swelling of the material in aggressive hot liquids.

The copolyamide of the invention preferably comprises a content of between 1 and 35% by mole, in particular between 2 and 30% by moles, and most particularly between 7 and 25% by moles of fatty acid dimers.

Furthermore, the copolyamide of the invention preferably comprises polyether diamines in a content of between 0.5 and 25% by moles, in particular between 1 and 22% by moles and very particularly between 1.5 and 14% by moles per relative to the total number of moles of the components of the copolyamide.

The copolyamide also optionally comprises piperazine in a content of between 0 and 30% by mole, and in particular between 0 and 22% by mole relative to the total number of moles of the components of the copolyamide.

Advantageously, the copolyamide according to the invention is derived exclusively from monomers comprising acid, amine or alcohol functions. The copolyamide also advantageously comprises mainly carboxylic acid chain ends.

The copolyamide according to the invention comprises from 30 to 99.5% by mole of unit X and from 0.5 to 70% by mole of unit Y, preferably from 35 to 95% by mole of unit X and of 5 to 65 mole% of Y unit, and more particularly 40 to 90 mole% of X unit and 10 to 60 mole% of Y unit. The molar percentages of the units X, Y and optionally Z are calculated by calculating the percentage of the number of moles of monomers constituting the unit X for example relative to the sum of the numbers of moles of all the monomers constituting the copolyamide , that is to say X, Y and possibly Z, when it is present, and this excluding the chain limiter: the diamine or the diacid in excess is not counted. The following formula illustrates the calculation:

[Form 1]

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

The copolyamide according to the invention has a Tg of less than 0 ° C. The noted glass transition temperature can be determined by differential scanning calorimetry (DSC) according to ISO 11357-2: 2013, Plastics -Differential Scanning Calorimetry (DSC) Part 2. Heating and cooling rates are 20 ° C / min.

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

Preferably, the copolyamide of the invention exhibits a threshold stress at 23 ° C, as measured according to the ISO 527 standard, from 4 to 12 MPa, preferably from 5 to 11.5 MPa and very particularly from 6 to 11 MPa.

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

[0068] According to one embodiment of the invention, the copolyamide comprises only the two units X and Y defined above.

[0069] According to another embodiment, the semi-crystalline hot-melt copolyamide according to the invention may comprise an additional unit. The copolyamide according to the invention can be represented according to the following formula (2): X / Y / Z (2) in which

-the pattern X is as defined above,

the Y pattern is as defined above,

-the Z unit is a unit obtained by the polycondensation of one unit (diamine in Cf). (Cg diacid), with f representing the number of carbon atoms of the diamine and g representing the carbon number of the diacid, f being between 4 and 48 and g being between 4 and 48, the diamine in Cf being chosen by aliphatic diamines and cycloaliphatic diamines,

-the copolyamide not containing ethylene diamine,

the copolyamide comprising from 30 to 99.5% by mole of unit X and from 0.5 to 70% by mole of units Y and Z,

- copolyamide having a melt viscosity measured according to the ASTM D3236-88 standard (validated in 2009) of between 0.5 and 100 Pa.s at 200 ° C,

-the copolyamide having a Tg of less than 0 ° C.

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

Cf diamine denotes diamines as defined above for Cd diamine. Cg diacid denotes diacids as defined above Ce diacid.

Preferably, the copolyamide according to the invention comprises at least one of the units chosen from PA pip.36, PA pip44, PA POP 40036, PA POP4006, PA POP40044, PA POP 200036, PA POP2000.6, PA POP200044

Preferably, the Z unit comprises a diacid comprising more than 5 carbon atoms as a Cg diacid.

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

Particularly preferably, the copolyamide according to the invention comprises an X unit chosen from an amino acid and a lactam, a Y unit comprising a polyetheramine as Cd diamine and a diacid comprising at least 6 carbon atoms as as a C-diacid, a Z unit comprising piperazine as a Cf-diamine and a diacid comprising at least 6 carbon atoms as a C8-diacid.

According to another preferred embodiment, the C6 diacid and C8 diacid are C36 acid dimers.

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

Particularly preferably, the copolyamide according to the invention comprises an X unit chosen from an amino acid and a lactam, a Y unit comprising a polyetheramine as a Cd diamine and a diacid comprising 36 carbon atoms as a diacid in Ce, a Z unit comprising piperazine as Cf diamine and a diacid comprising 36 carbon atoms as Cg diacid.

The copolyamide according to the invention comprises from 30 to 99% by mole of unit X, from 0.5 to 69.5% by mole of unit Y and from 0.5 to 69.5% by mole of unit Z ; preferably from 50 to 97 mole% of the X unit, from 1.5 to 48.5 mole% of the Y unit and from 1.5 to 48.5 mole% of the Z unit. According to another preferred embodiment, the copolyamide according to the invention does not contain any amine containing less than 7 carbon atoms, with the exception of piperazine.

Preferably, the copolyamide according to the invention comprises at least one of the units chosen from PA6, PA11, PA1010, PA 1012, PA 12, PA pip36, PA pip44 PA POP40036, PA POP40010, PA POP4006 and their mixture.

Preferably, the copolyamide according to the invention is chosen from the following structures: PA6 / pip36, PA 11 / pip36, PA 12 / pip36, PA 1010 / pip36, PA 1012 / pip36, PA 6 / POP40036, PA 11 / POP40036, PA 12 / POP40036, PA 1010 / POP40036, PA 1012 / POP40036, 6 / POP4006,

PA 11 / POP4006, PA 12 / POP4006, PA 1010 / 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, PA 12 / POP40010 / pip10 , PA 1010 / POP40010 / pip10, PA 1012 / POP40012 / pip12. More preferably, the copolyamide according to the invention is chosen from PA11 / POP40036 / pip36, PA6 / POP40036 / pip36, PA11 / POP200036 / pip36 and PA6 / POP200036 / pip36.

[0083] 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 X units, one or more different Y units and one or more different Z units.

Chain limiter

The copolyamides of the invention are synthesized in a conventional manner, in the presence, if necessary, of a chain limiter or chain terminating agents.

The chain terminating agents suitable for reacting with the amino terminal function can be acids monocarboxylic anhydrides, such as phthalic anhydride, monohalogenated acids, monoesters or monoisocyanates.

Preferably, monocarboxylic acids are used. They can be chosen from aliphatic monocarboxylic acids, such as acetic acid, propionic acid, lactic acid, valeric acid, caproic acid, capric acid, lauric acid, acid. tridecylic, 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-naphthalenecarboxylic acid, b-naphthalenecarboxylic acid, methylnaphthalene carboxylic acid and phenylacetic acid; and their mixtures. The preferred compounds are aliphatic acids, and in particular acetic acid, propionic acid, lactic acid, valeric acid, caproic acid, capric acid, lauric acid, tridecylic acid, myristic acid, palmitic acid and stearic acid.

Among the chain terminating agents suitable for reacting with the acid terminal function, mention may be made of monoamines, monoalcohols and monoisocyanates.

Preferably, monoamines are used. They can be chosen 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 and naphthylamine; and their mixtures.

The preferred compounds are butylamine, hexylamine, octylamine, decylamine, laurylamine, stearylamine, cyclohexylamine and aniline.

The chain limiters can also be a dicarboxylic acid, which is introduced in excess relative to the stoichiometry of the diamine (s); or else a diamine which is introduced in excess relative to the stoichiometry of the diacid (s).

Preparation process

A subject of the invention is also the process for preparing the copolyamide according to the invention. In a suitable reactor equipped with a mixer, all of the reagents are charged and then heated under nitrogen at a temperature between 190 to 250 ° C for 20 to 180 minutes (until the volume of distillate no longer increases under flushing d 'nitrogen). Then, the reactor is placed under vacuum at a pressure between 0.5 and 300 mBar and maintained under these conditions until the desired viscosity is obtained.

[0092] Composition

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

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

It is preferred that the composition exclusively comprises compounds with an acid, amine or alcohol function. In particular, it is preferred that the composition does not contain isocyanate or urethane compounds.

Advantageously, the composition of the invention does not include an alkaline catalyst. Indeed, this type of catalyst can affect chemical resistance.

The composition according to the invention can be used to produce molded parts which can be produced by known methods, for example by extrusion, casting molding, injection molding, compression molding, transfer molding, etc. However, according to the invention, the composition is made into molded parts by low pressure injection molding. This injection molding cycle can comprise the following different steps: a) the mold is closed after the parts to be bonded have been inserted, b) the molten composition according to the invention is injected into the mold up to a pressure of between 0.5 and 50 bar and optionally subjected to a holding pressure, c) the molding composition is allowed to solidify by cooling, d) the mold is opened, e) the injection molded parts are removed from the mold.

The low pressure injection molding process generally operates in the range of 2 to 40 bar, the temperature being between 160 and 250 ° C.

Thus, the composition according to the invention is suitable for injection at low pressure, that is to say at a pressure less than 100 bars, preferably less than 50 bars.

Use

[0100] According to yet another aspect, the present invention relates to the use of copolyamide as defined above for the encapsulation of electronic devices, also called overmolding or molding, preferably located under the bonnet of a vehicle or in medical devices.

The present invention also relates to the use of at least one copolyamide as defined above for the manufacture of a hot-melt adhesive, in particular a web, a film, granules, a filament, a grid, a powder or a suspension.

[0102] The invention finally relates to the use of a semi-crystalline copolyamide copolyamide comprising at least two units corresponding to the following formula (3): X / Y (3) in which

-the unit X is a crystalline unit obtained by the polycondensation of a unit selected from a C5 to C12 alpha, omega-aminocarboxylic acid, a C6 to C12 lactam and a unit (diamine in Ca). (Cb diacid), with a representing the number of carbon atoms of the diamine and b representing the carbon number of the diacid, a and b being greater than or equal to 4,

-the Y unit is a unit obtained by the polycondensation of one unit (Cd diamine). (Ce diacid), with d representing the number of carbon atoms of the diamine and e representing the carbon number of the diacid, d being between 4 and 48 and e being between 6 and 48 - the Cd diamine being chosen by aliphatic diamines, cycloaliphatic diamines and polyethers terminating amine chains,

-the copolyamide not containing ethylene diamine,

- copolyamide having a melt viscosity measured according to the ASTM D3236-88 standard (validated in 2009) of between 0.5 and 70 Pa.s at 200 ° C,

copolyamide having a Tg of less than 0 ° C., for manufacturing hot-melt adhesives exhibiting improved chemical resistance after aging of the material when hot to automotive fluids.

It turns out that the copolyamide of formula (3) has good adhesion properties on various substrates, such as epoxy resins loaded with glass fibers, PA6, PBT, PA6 loaded with glass fibers, PA6.6 or else on metal surfaces, good mechanical properties, satisfactory processability for injection at low pressure, and above all improved chemical resistance to automotive fluids, after hot aging of the material.

[0104] For the purposes of the present invention, automotive liquid is understood to mean brake fluid, engine oil, gasoline, such as diesel, bio-diesel, battery liquid, and cooling liquid. By improved chemical resistance after hot aging of the material, is meant a swelling of less than 20% by mass.

Preferably, the X, Y and optionally Z units, thus having the other characteristics of the copolyamide, are as defined above. The invention is illustrated by the figure and the following examples which are in no way limiting.

Description of figures

[0108] [Fig.1] shows the curves obtained following the tensile tests carried out on dumbbells formulated from copolyamides according to the invention and from a comparative material. On the x-axis, the percentage of strain is shown and on the y-axis, the stress expressed in MPa is shown.

Examples

1. Preparation of the copolvamides The synthesis was carried out according to a one-step process as follows.

In a suitable reactor equipped with a mixer, all the reagents were charged and then heated under nitrogen at a temperature of 235 ° C for 90 minutes. Then, the reactor is evacuated to 100 mBar and maintained under these conditions until the desired viscosity is obtained. [0110] The following copolyamides are prepared from the reagents listed in Table 1 below.

[0111] [Table 1]

[0112; In this table :

[0113] Amino acid-11 refers to 11-aminoundecanic acid.

DA 10 denotes decanediamine.

DC 10 denotes sebacic acid. Baxxodur ^® EC 302 is marketed by the company BASF and refers to a polyoxypropylene diamine of molecular weight 400 g. mol ¹ .

Pripol 1013 ^® is marketed by Croda and means the dimer acid C36.

Jeffamine ^® D 2000 is marketed by Huntsman and designates a polyoxypropylene diamine of molecular weight 2000 g. mol

1

[0114] Examples A and G are comparative copolyamides, Examples B to F are copolyamides according to the invention.

[0115] An excess of sebacic acid was used as a chain limiter during the synthesis of Example B according to the invention. An excess of

Pripol®1013 was used as a chain limiter during the synthesis of Examples C, D, E and F according to the invention.

The synthesized copolyamides exhibit the following compositions and characteristics. The Tg is measured by differential scanning calorimetry

(DSC) according to ISO 11357-2: 2013, Plastics -Differential Scanning Calorimetry (DSC) Part 2. Heating and cooling rates are 20 ° C / min.

[0118] The melt viscosity is measured using a Brookfield rheometer using the SC 4-27 module according to ASTM D3236-88

(2009) at 200 ° C. [0119] [Table 2]

[0120] ^* ND = not determined

[0121] 2. Preparation of samples

[0122] The copolymers synthesized were ground. The granules obtained were processed by compression using a Darragon plate press heated to 220 ° C. and a mold for making plates of 100 cm ² having a thickness of 2 mm. The following protocol was used:

1 min of compression at 220 ° C at 1 bar, 2 minutes of compression at 220 ° C 50 bars,

4 minutes of cooling (circulation of cold water in the press trays) at 50 bars.

[0123] Dumbbells were then cut from these plates using a cookie cutter making it possible to cut 1 BA dumbbells (Annex A of the ISO 527-2: 2012 standard) in order to carry out the tensile tests by following ISO 527-2: 2012.

[0124] 3. Evaluation of the samples

[0125] 3.1. Swelling resistance The aging of the samples in a brake fluid is evaluated. The samples are placed in DOT 5.1 brake fluid at 80 ° C. for 24 hours. The swelling of each sample is then measured by making the difference between the mass of the dumbbell measured before aging and the mass of the dumbbell measured after aging. In order to obtain reproducible results, the aged 1 BA dumbbells are wiped so that no liquid remains on the surface of the sample. The results of the swelling test are reported in Table 3 below. [0127] [Table 3]

[0128] The results obtained show that the copolyamides according to the invention are much more resistant to aging in hot brake fluid than the comparative material. [0129] 3.2. Mechanical resistance

The tensile tests were performed on 1 BA dumbbells (Annex A of ISO 527-2: 2012) following ISO 527-2: 2012.

The results obtained are shown in Figure 1 and Table 2 above. These results show that the copolyamides according to the invention exhibit better mechanical properties than the comparative material.

Furthermore, it is noted that the copolyamides of Comparative Examples A and G exhibit a high modulus and a high threshold stress, which is not desirable for the overmolding of parts by injection at low pressure. Copolyamides comprising units derived from an acid dimer (Examples C to F) exhibit a clearly better suited profile of mechanical properties, and they are therefore clearly more advantageous for this application.

Claims

[Claim 1] Semi-crystalline copolyamide comprising at least two units corresponding to the following formula: X / Y in which

the X unit is a crystalline unit obtained by the polycondensation of a unit chosen from a C5 to C12 alpha, omega-aminocarboxylic acid, a C6 to C12 lactam and a unit (Ca diamine). (Cb diacid with a representing the number of carbon atoms of the diamine and being greater than 6 and b representing the carbon number of the diacid and being greater than or equal to 6,

-the Y unit is a unit obtained by the polycondensation of one unit (Cd diamine). (Ce diacid), with d representing the number of carbon atoms of the diamine and e representing the carbon number of the diacid,, d being between 4 and 48 and e being between 6 and 48, the Cd diamine being chosen by aliphatic diamines, cycloaliphatic diamines and polyethers terminating amine chains,

-the copolyamide not containing ethylene diamine,

-the copolyamide having a Tg of less than 0 ° C.

[Claim 2] A copolyamide according to claim 1, characterized in that the Cd diamine is an amine chain terminated polyether.

[Claim 3] Copolyamide according to any one of the preceding claims, characterized in that it comprises an X unit chosen from 11-amino-undecanoic acid, caprolactam, lauryllactam, PA 1010, and PA 1012 and PA 1014 and a Y unit comprising a polyetheramine and / or piperazine as Cd diamine and a diacid comprising more than 6 carbon atoms as Ce diacid.

[Claim 4] Copolyamide according to any one of the preceding claims, characterized in that it comprises an additional unit, the copolyamide then has the following formula (2):

XIYIZ (2) in which

-the unit X is as defined in claim 1,

-the Y unit is as defined in claim 1,

-the copolyamide not containing ethylene diamine,

-the copolyamide having a Tg of less than 0 ° C.

[Claim 5] Copolyamide according to any one of the preceding claims, characterized in that the viscosity in the molten state is between 0.5 and 70 Pa.s at 200 ° C, preferably from 1 to 50 Pa.s at 200 ° C, and more particularly from 2 to 30 Pa.s at 200 ° C.

[Claim 6] Copolyamide according to any one of the preceding claims, characterized in that it comprises at least one of the units chosen from PA6, PA11, PA1010, PA 1012, PA 12, PA pip36, PA pip44 POP40036, PA POP40010, PA POP4006 and their mixture.

[Claim 7] Copolyamide according to any one of the preceding claims, characterized that it comprises an X unit chosen from an amino acid and a lactam, a Y unit comprising a polyetheramine as Cd diamine and a diacid comprising more than 6 atoms of carbon as C6 diacid, a Z unit comprising piperazine as Cf diamine and a diacid comprising more than 6 carbon atoms as C8 diacid.

[Claim 8] Copolyamide according to any one of the preceding claims, characterized in that it is of the following formula: PA6 / pip36, PA 11 / pip36, PA 12 / pip36, PA 1010 / pip36, PA 1012 / pip36 PA 6 / POP40036, PA 11 / POP40036, PA 12 / POP40036, PA 1010 / POP40036, PA 1012 / POP40036, 6 / POP4006, PA 11 / POP4006, PA 12 / POP4006, PA 1010 / 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 / pip.10, PA 11 / POP40010 / pip10, PA 12 / POP40010 / pip.10, PA 1010 / POP40010 / pip.10, PA 1012 / POP40012 / pip.12.

[Claim 9] A composition comprising the copolyamide as defined in any one of claims 1 to 8.

[Claim 10] Composition according to claim 9, characterized in that it comprises additives chosen from antioxidants, UV stabilizers, thermal stabilizers, plasticizers, nucleating agents, tackifiers, impact modifiers, flame retardants , antistatic agents, reinforcing agents, lubricants, organic and inorganic fillers, optical brighteners, release agents, pigments, dyes, catalysts and mixtures thereof.

[Claim 11] Composition according to claim 9 or 10, characterized in that it is suitable for being injected at a pressure below 100 bars, preferably below 50 bars.

[Claim 12] Use of the copolyamide as defined in any one of claims 1 to 8 or of the composition as defined in any one of claims 9 to 11 for the encapsulation of electronic devices, preferably located under the engine hood of a vehicle or in medical devices.

[Claim 13] Use of a semi-crystalline copolyamide comprising at least two units corresponding to the following formula: X / Y in which the unit X is a crystalline unit obtained by the polycondensation of a unit chosen from an alpha, omega acid -C6 to C12 aminocarboxylic, a C6 to C12 lactam and a unit (Ca diamine). (diacid in Cb), with a representing the number of carbon atoms of the diamine and b representing the carbon number of the diacid, a and b being greater than or equal to 4,

- the Y unit is a unit obtained by the polycondensation of a unit (diamine in Cd). (Ce diacid), with d representing the number of carbon atoms of the diamine and e representing the carbon number of the diacid, d being between 4 and 48 and e being between 6 and 48, the Cd diamine being chosen by aliphatic diamines, cycloaliphatic diamines and polyethers terminating amine chains,

-the copolyamide not containing ethylene diamine,

- copolyamide having a viscosity in the molten state measured according to standard ASTM D3236-88 (2009) of between 0.5 and 70 Pa.s at 200 ° C,

copolyamide having a Tg of less than 0 ° C., for manufacturing hot-melt adhesives exhibiting improved chemical resistance after aging of the material when hot to automotive fluids. [Claim 14] Use according to claim 13, characterized in that the X and Y units are as described in any one of claims 1 to 8.