Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J177/00—Adhesives based on polyamides obtained by reactions forming a carboxylic amide link in the main chain; Adhesives based on derivatives of such polymers
  • C09J177/06—Polyamides derived from polyamines and polycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
  • C08G69/40—Polyamides containing oxygen in the form of ether groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/001—Conductive additives
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/002—Physical properties
  • C08K2201/005—Additives being defined by their particle size in general

Definitions

• the present invention relates to a hot-melt adhesive composition for encapsulating electronic devices, a process for preparing such a composition and its use.
• polyamides as hot-melt adhesives to encapsulate electronic or mechanical devices used for example in the automotive fields or in the medical field.
• plastic materials are generally used to protect batteries, whether in an automobile or on a smaller scale, such as the shell of a mobile phone.
• the substrates to be encapsulated can be metals, such as copper or polymers such as, for example, materials making up printed circuits.
• these materials must be electrically insulating, in order to avoid possible short circuits. They must also be heat conductors in order to allow, for example, a battery, if this is the element to be encapsulated, to evacuate the heat it generates during its use.
• the encapsulation of the parts needs to be carried out at low pressure, so as not to damage the part to be molded.
• Encapsulation is a delicate process. The material used to encapsulate the part is melted. It is then delicately deposited hot on the element to be encapsulated. The pressure at the nozzle outlet of the molten material is qualified as low pressure. The term “wetting” is used to define this encapsulation. Indeed, if the pressure at the nozzle outlet is higher, the force applied to the part to be molded during the deposition of the ground material can damage the part, said Several low-pressure injection processes are known for encapsulating parts.
• epoxy potting has the disadvantage of being relatively long, leading to low productivity due to the relatively slow reaction time.
• the process by chemical vapor deposition is used in the field of encapsulation. However, this process is known to be dangerous. Thus, new materials are sought which must respond both to specific physico-chemical properties and must allow an easier low-pressure encapsulation process.
• the materials are in a molten state, generally in a melter, for a relatively long period of time.
• the known compositions have been observed to undergo phase segregation. This loss of homogeneity over time results in a difference in properties between the encapsulated product manufactured at the start of production, with the homogeneous material, and the encapsulated product manufactured at the end of production, with an inhomogeneous material.
• the sedimentation of the fillers, making the molten material too dense tends to clog the outlet nozzles. Then, over time, these relatively abrasive fillers deteriorate manufacturing facilities.
• the invention relates to a hot-melt adhesive composition
• a hot-melt adhesive composition comprising: i) at least one semi-crystalline aliphatic copolyamide comprising at least two units corresponding to the following formula (1): /Y (1)
• the X unit is a semi-crystalline unit obtained by the polycondensation of a unit chosen from an alpha, omega-aminocarboxylic acid in C6 to C18, a lactam in C6 to C18 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 being between 2 and 18 and b being between 4 and 18, the Ca diamine and the Cb diacid being linear or branched aliphatic, cycloaliphatic, saturated or unsaturated,
• the unit Y is a unit obtained by the polycondensation of a 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 and e being between 2 and 48, the Cd diamine and the Ce diacid being linear or branched aliphatic, cycloaliphatic, saturated or unsaturated, the Cd diamine possibly being a polyether amine, the unit Y having a Tg of less than 30°C, advantageously less than 20°C, very advantageously less than 0°C, the copolyamide having a viscosity in the molten state measured according to standard ASTM D3236-88 (2009) between 0.5 and 300 Pa.s at 200° C., the copolyamide constituting the matrix of the composition, and ii) from 3 to 35% by weight relative to the total weight of the composition of at least one thermally conductive filler , the carbon atom content of which is between
• the invention also relates to a method for preparing the composition according to the invention.
• the invention finally relates to the use of the composition for encapsulating electronic devices.
• hot melt is meant within the meaning of the present invention the ability of the composition to melt under the effect of heat.
• copolyamide present in the composition according to the invention is semi-crystalline and aliphatic.
• polystyrene-crystalline copolyamide covers copolyamides which exhibit both a glass transition temperature Tg and a melting temperature Tm.
• Tg and Tf can be determined respectively according to ISO 11357-2:2013 and 11357-3:2013.
• polyamides The nomenclature used to define polyamides is described in standard ISO 1874-1:1992 "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.
• PA denotes polyamide
• L denotes the number of carbon atoms of the amino acid or of the lactam.
• the polyamide is obtained by the polycondensation of the amino acid or the lactam comprising L carbon atoms.
• M designates the number of carbon atoms of the diamine
• N designates the number of carbon atoms of the diacid.
• the X unit is a semi-crystalline unit obtained by the polycondensation of a unit chosen from an alpha, omega-aminocarboxylic acid in C6 to C18, a lactam in C6 to C18 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 being between 2 and 18 and b being between 4 and 18, the Ca diamine and the Cb diacid being linear or branched aliphatic, cycloaliphatic, saturated or unsaturated,
• the unit Y is a unit obtained by the polycondensation of a 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 and e being between 2 and 48, the Cd diamine and the Ce diacid being aliphatic linear or branched, cycloaliphatic, saturated or unsaturated, the Cd diamine possibly being a polyether amine, the unit Y having a Tg of less than 30°C, advantageously less than 20°C, very advantageously less than 0°C, the copolyamide having a viscosity in the molten state measured according to standard ASTM D3236-88 (2009) of between 0.5 and 300 Pa.s at 200° C. the copolyamide constituting the matrix of the composition.
• the polyamide of formula (1) has a ratio: number of carbon atoms to number of nitrogen atoms, denoted C/N greater than or equal to 8.
• semi-crystalline unit within the meaning of the present invention a polyamide, which has a melting temperature (Tm) in DSC according to the ISO 11357-3: 2013 standard, and an enthalpy of crystallization during the cooling step at a speed of 5 K/min in DSC measured according to standard ISO 11357-3 of 2013 greater than 15 J/g, preferably greater than 30 J/g.
• Tm melting temperature
• the X motif can result from the polycondensation of one or more C6 to C12 alpha, omega-aminocarboxylic acids.
• the alpha, omega-aminocarboxylic acid is chosen from amino-7-heptanoic acid, amino-11-undecanoic acid and amino-12-dodecanoic acid.
• the X motif can result from the polycondensation of one or more C6 to C12 lactams.
• the lactam is chosen from caprolactam, oenantholactam and lauryllactam.
• the X pattern can result from the polycondensation of a unit (diamine to Ca). (Cb diacid), with a representing the number of carbon atoms of the diamine and b representing the number of carbon atoms of the diacid, a being between 2 and 18 and b being between 4 and 18. More particularly, b is between 5 and 18.
• the Ca diamine can be chosen from aliphatic, linear or branched diamines, cycloaliphatic diamines.
• the Ca-diamine When the Ca-diamine is aliphatic and branched, it may have one or more methyl or ethyl substituents on the main chain.
• it can advantageously be chosen from 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 2-methyl-1,8-octanediamine.
• the Ca diamine is chosen from ethylene diamine, hexamethylene diamine, decanediamine and piperazine.
• the Cb diacid can be chosen from aliphatic, linear or branched diacids, cycloaliphatic diacids.
• the diacid when it is cycloaliphatic, it may comprise the following carbon skeletons: norbornyl, cyclohexyl, dicyclohexyl, dicyclohexylpropane.
• the unit X is chosen from caprolactam, oenantholactam and lauryllactam, amino-7-heptanoic acid, amino-11-undecanoic acid and amino-12-dodecanoic acid, PA 26, PA 29, PA 210, PA 212, PA 214, PA 218, PA 56, PA59, PA510, PA 66, PA 69, PA610, PA 512, PA612, PA 514, PA614, PA618, PA pip10, PA pip12, PA1010, PA1012, PA1014, PA1018, PA1210, PA1212, PA1214, PA1218.
• the unit X is chosen from caprolactam, lauryllactam, amino-11-undecanoic acid, PA 26, PA 29, PA 210, PA 212, PA 214, PA 218, PA59, PA510, PA 69, PA610, PA 512 and PA612.
• the unit X is chosen from an amino acid and a lactam or PA 26, PA 29, PA 210, PA 212, PA 214, PA 218, PA59, PA510, PA 66, PA 69 PA610, PA 512, PA612, more particularly, the X unit is chosen from amino acids and the lactams have a number of carbon atoms greater than 6. More particularly, the X unit is a PA6, a PA11 a PA12, a PA 210, a PA 212, a PA 69, a PA610, or a PA612.
• the Y unit is obtained by the polycondensation of one unit (Cd diamine).
• 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 and e being between 2 and 48, the Cd diamine and the Ce diacid being aliphatic linear or branched, saturated or unsaturated, the Cd diamine being chosen from aliphatic diamines, cycloaliphatic diamines and polyetheramines.
• the Cd diamine can be chosen from aliphatic, linear or branched diamines, cycloaliphatic diamines, as defined above for the Ca diamines.
• the Cd diamine can also come from the amination of polymerized fatty acids, as defined below.
• the Cd diamine can be a C36 or C44 diamine.
• the Cd diamine can also be a polyetheramine, i.e. a polyoxyalkylene diamine.
• a polyoxyalkylene diamine Preferably, it is a polyoxyalkylene chain carrying an amine group at the end of the chain.
• the polyoxyalkylene chain preferably comprises oxyethylene (POE), oxypropylene (POP), oxytetramethylene (POTM) groups, alone or as a mixture. When the groups are mixed, the mixtures POE and POP or else POTM and POP are preferred.
• polyetheramine is preferably chosen from commercially available products, in particular sold by Huntsman under the Jeffamine® and Elastamine® brands (for example Jeffamine® D400, D2000, ED 2003, XTJ 542, Elastamine® RT 1000, RP 405, RP 2009) or under the Baxxodur® brand by BASF (for example Baxxodur® EC 302, EC 301; EC 303, EC 311).
• the number-average molecular mass 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 .
• the Cd diamine can also come from the amination of polymerized fatty acids, as defined below. These diamines are commercially available under the trade name “Versamine®” sold by Cognis Corporation (BASF) and under the trade name Priamine® from Croda.
• the Ce diacid can be chosen from aliphatic, linear or branched diacids, cycloaliphatic diacids, as defined above for the Cb diacids.
• the C6 diacid can come from polymerized fatty acids. These polymerized fatty acids designate the compounds produced from coupling reactions of unsaturated fatty acids, which lead to mixtures of products bearing two acid functions (called acid dimers) or three acid functions (called acid trimers).
• This coupling can be a combination or condensation reaction of 2 moles of an unsaturated monocarboxylic acid, the monoacids possibly being identical or different.
• This dimerization reaction can be carried out according to catalytic or non-catalytic polymerization methods according to known methods.
• the C36 dimer diacid can be obtained by dimerization of an unsaturated C18 monoacid, such as oleic acid, linoleic acid, linolenic acid and their mixture.
• these mixtures are present for example in tall oil.
• these mixtures mainly comprise the dimer, and in lesser quantities the monomer, the trimer and oligomers.
• the fatty acid dimers are mainly obtained from 75% to more than 98%, in a mixture with in particular the monomer, the “1 and 1/2 mer” and the corresponding trimer.
• Dimer diacids can be obtained from myristoleic acid in C14, palmitoleic acid in C16, sapienic acid in C16, oleic acid in C18, elaidic acid in C18, trans-vaccenic acid in C18, linoleic acid in C18, linolelaidic acid in C18, alpha-linolenic acid in C18, gamma-linolenic acid in C18, 11-eicosenoic acid in 20, eicosapentaenoic acid in 20, dihomo-gamma-linolenic acid at C20, arachidonic acid at 20, erucic acid at 22, clupanodonic acid at C22, docosahexaenoic acid at C22, nervonic acid at 24 and their mixture.
• the polymerized fatty acids are marketed and in particular the product with the trade name Pripol® marketed by the company Croda can be used as well as the product with the trade name Empol® marketed by the company Cognis or the product with the trade name Unydime® marketed by the company Kraton or else the product with the trade name Radiacid® marketed by the company Oleon.
• the fatty acid dimers can then be transformed into amino 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.
• the diacids used for the Y unit are acid dimers, and more particularly the C36 and C44 dimers are used.
• the unit Y is chosen from PA 236, PA 536, PA 636, PA 1036, PA pip36, PA pip44, PA 244, PA 544, PA 644, PA 1044, PA POP36, PA POP44, PA POP6, PA POP9, PA POP10, PA POP12, PA POP14, POP being a polyetheramine with a molar mass of between 60 and 2000 g/mol.
• the Y unit of the copolyamide according to the invention preferably has a Tg of less than 30°C, advantageously 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.
• the copolyamide according to the invention comprises from 30 to 99.5% by mole of X unit and from 0.5 to 70% by mole of Y unit, preferably from 40 to 98% by mole of X unit and from 2 to 60 mol% of unit Y, and more particularly from 50 to 90% by mol of unit X and from 10 to 50% by mol of unit Y.
• the molar percentages of the units X and Y are measured by calculating the percentage of the number of moles of monomers constituting the unit X for example with respect to the sum of the numbers of moles of all the monomers constituting the copolyamide, that is to say say X and Y, excluding the chain limiter: the excess diamine or diacid is not counted.
• the following formula illustrates the calculation: n(monomers of unit X) * 100
• 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 300 Pa.s at 200° C., preferably from 0.5 to 200 Pa. s, even more preferably from 1 to 100 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 the ASTM D3236-88 (2009) standard at 200°C.
• the copolyamide according to the invention preferably has a Tg of less than 20°C, advantageously less than 0°C.
• the noted glass transition temperature can be determined by differential scanning calorimetry (DSC) according to the standard ISO 11357-2: 2013, Plastics -Differential Scanning Calorimetry (DSC) Part 2. The heating and cooling rates are 20°C/min.
• the copolyamide according to the invention comprises at least one of the units chosen from PA 26, PA 29, PA 210, PA 212, PA 214, PA 218, PA 56, PA 59, PA 510, PA 512, PA66, PA 69, PA 610, PA 612, PA6, PA11 , PA 12, PA1010, PA 1012, PA 1212, PA pipi 0, PA pip36, PA pip44, PA POP40036, PA POP40044, PA POP40010, PA POP4006, PA POP200036, PA POP200044, PA PQP200010, PA POP20006, PA3636, PA3644, PA 4436, PA 4444 and mixtures thereof.
• the copolyamide according to the invention is chosen from the following structures: PA 26/pip36, PA 210/pip36, PA 212/pip36, PA 214/pip36, PA 218/pip36, PA 59/pip36, PA 510/ pip36, PA 512/ pip36, PA 610/ pip36, PA 612/ pip36, PA6/ pip36, PA1010/ pip36, PA 1012/ pip36, PA 1212/ pip36, PA 26/ pip44, the PA 212/ pip44, PA 214/ pip44, PA 218/ pip44, PA 59/ pip44, PA 510/ pip44, PA 512/ pip44, PA 610/ pip44, PA 612/ pip44, PA6/ pip44, PA1010/ pip44, PA 1012/ pip44, PA 1212/ pip44, PA 26/ POP40036, PA 210/ POP40036, PA 212/
• the copolyamide according to the invention comprises an X unit chosen from a diamine.diacid unit and a Y unit comprising piperazine as Cd diamine and a diacid comprising more than 6 carbon atoms as diacid in this.
• the C6 diacid is a C36 or C44 acid dimer.
• the copolyamide according to the invention comprises an X unit of (Ca-diamine) type. (Cb diacid) comprising an average number of carbon atoms per nitrogen atom greater than or equal to 6 and a Y unit comprising piperazine as Cd diamine and a diacid comprising more than 6 carbon atoms as as Ce diacid.
• the copolyamide according to the invention comprises as C6 diacid an acid dimer or else a polyetheramine as Cd diamine.
• the copolyamide according to the invention is chosen from PA 26/pip36, PA 210/pip36, PA 59/pip36, PA 510/pip36, PA 512/pip36, PA 610/pip36, PA 210/ POP40036, PA 59/ POP40036, PA 510/ POP40036PA 610/ POP40036, PA 210/ PCP40010, PA 59/ POP4009, PA 510/ PCP40010, , PA 26/ POP4006, PA 210/ POP4006, PA 610/ POP4006, PA 26/ pip36/ POP40036, PA 210/ pip36/ POP40036, PA 510/ pip36/ POP40036, PA 610/ pip36/ POP40036, PA6/ pip36/ POP40036, PA 210/ pip36/ PCP200036, PA 59/ pip36/ PCP200036, PA 510/ pip36, PA 510/ pi
• the copolyamide consists of the two units X and Y defined above.
• the copolyamide comprises more than two X and Y units defined above.
• the copolyamide included in the composition according to the invention comprises at least three different units.
• the copolyamide according to the invention may comprise two X units and one Y unit, one X unit and two Y units or even two X units and two Y units.
• the copolyamide included in the composition according to the invention is a terpolyamide and a tetrapolyamide.
• the copolyamide according to the invention comprises fatty acid dimer, advantageously in a content of 1 to 35 mol%, preferably of 2 to 30 mol%, preferentially of 7 to 25 mol% with respect to the total number of moles of the copolyamide.
• the copolyamide according to the invention comprises a polyether diamine content of between 0.5 and 25 mol%, preferably between 1 and 22 mol%, preferably between 1.5 and 14 mol% relative to the total number of moles of the copolyamide.
• the piperazine content in the copolyamide is preferably less than 40 mol%, advantageously less than 30 mol%, very advantageously less than 20 mol% relative to the total number of moles of the copolyamide.
• copolyamides of the invention are synthesized in a conventional manner, in the presence if necessary of chain limiter or chain terminating agents.
• Chain terminators suitable for reacting with the amine terminal function can be monocarboxylic acids, anhydrides, such as phthalic anhydride, monohalo acids, monoesters or monoisocyanates.
• 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, tridecyl, myristic acid, palmitic acid, stearic acid, pivalic acid and isobutyric acid; alicyclic acids, such as cyclohexane carboxylic acid; aromatic monocarboxylic acids; such as benzoic acid, toluic acid, a-naphthalenecarboxylic acid, P-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid and phenylacetic acid; and their mixtures.
• aliphatic monocarboxylic acids such as acetic acid, propionic acid, lactic acid, valeric acid, caproic acid, capric acid, lauric acid, tridecyl, myristic acid, palmitic acid, stearic acid
• the preferred compounds are aliphatic acids, and in particular acetic acid, propionic acid, lactic acid, valeric acid, caproic acid, capric acid, lauric acid, tridecyl acid, myristic acid, palmitic acid and stearic acid.
• chain-terminating agents suitable for reacting with the acid terminal function mention may be made of monoamines, monoalcohols, monoisocyanates.
• 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.
• aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, laurylamine, stearylamine, dimethylamine, diethylamine, dipropylamine and dibutylamine
• alicyclic amines such as
• 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 with respect to the stoichiometry of the diamine or diamines; or alternatively a diamine which is introduced in excess relative to the stoichiometry of the diacid(s).
• the copolyamide present in the composition according to the invention is wholly or partly a recycled copolyamide.
• the polyamide is a recycled polyamide, it contains functions resulting from oxidation reactions chosen from imide, alcohol or carboxylic acid functions, preferably imides or alcohols, in a molar ratio relative to the amide functions higher than that of the same polyamide not recycled.
• said molar ratio of the functions resulting from oxidation reactions that is to say the sum of the number of moles of the imide, acid and alcohol functions over the number of moles of amide functions of the copolyamide is comprised between 1/10000 and 1/20.
• the copolyamide sample is prepared by dissolving the copolyamide in dichloromethane-d2, adding HFIP (hexafluoroisopropanol).
• said molar ratio of the imide functions is between 1/1000 and 1/20, in particular between 1/500 and 1/20, in particular between 1/200 and 1/50.
• said molar ratio of the carboxylic acid functions is between 1/5000 and 1/20, in particular between 1/3000 and 1/50, very advantageously between 1/500 and 1/25.
• said molar ratio of the alcohol functions is between 1/1000 and 1/20 and advantageously between 1/1000 and 1/25 very advantageously between 1/200 and 1/50.
• the copolyamide present in the composition preferably has a melting point of between 100 and 220°C, advantageously between 120 and 200°C, very advantageously between 130 and 180°C.
• the water content of the copolyamide after exposure to 23° C. and 50% relative humidity (measurement carried out at equilibrium) is preferably between 0.1 and 1.2% by weight, advantageously from 0.15 to 0.7% by weight relative to the total weight of the copolyamide.
• copolyamide described above constitutes the matrix of the composition according to the invention.
• the composition according to the invention comprises from 3 to 35% by weight relative to the total weight of the composition, of at least one thermally conductive filler, the carbon atom content of which is between 80 and 100% relative to the number of atoms constituting the charge.
• the filler comprises 94 to 99.99% carbon atoms.
• the carbonaceous filler can be chosen from natural graphites, synthetic graphites, expanded graphites, graphenes, carbon blacks and carbon fibers.
• the filler is chosen from natural graphites, synthetic graphites and expanded graphites.
• the graphite used in the composition according to the invention can be produced synthetically or naturally. There are three types of naturally produced graphite available commercially. These are flake graphite, amorphous graphite and crystalline graphite.
• Amorphous graphite is not really amorphous as its name suggests but is actually crystalline. Amorphous graphite is available in average sizes from about 5 micrometers to about 10 centimeters. Crystalline graphite usually has a vein-like appearance on its outer surface, hence its name. Crystalline graphite is commercially available in flake form from Asbury Graphite and Carbon Inc Carbons.
• Synthetic graphite can be produced from coke and/or pitch which are derived from petroleum or coal. Synthetic graphite is of higher purity than natural graphite, but is not as crystalline.
• One type of synthetic graphite is electrographite, which is produced from calcined petroleum coke and coal tar pitch in an electric furnace. Another type of synthetic graphite is produced by heating calcined petroleum pitch to 2800° C.
• Graphite Synthetic tends to have lower density, higher porosity and higher electrical resistance than natural graphite.
• the thermally conductive filler has a median average particle size D50 ranging from 0.5 to 500 micrometers. Within this range, filler particles having D50 sizes comprised from 1 to 200 ⁇ m, preferably from 20 to 150 ⁇ m can be advantageously used.
• the thermally conductive filler has a median average particle size D90 ranging from 1 to 400 micrometers, advantageously from 2 to 200 ⁇ m, very advantageously from 5 to 150 ⁇ m.
• D50 and D90 can be estimated according to the ISO 13320-1:1999 standard.
• the thermally conductive filler does not comprise particles with a diameter greater than 500 ⁇ m, advantageously no particles with a diameter greater than 400 ⁇ m.
• the impurities are preferably chosen from the following chemical species: SiO2, Fe2O3, Al2O3, CaO, MgO, K2O, Na2O, TiO2, MnO, P2O5.
• the BET specific surface measured according to ISO 9277:2010 is between 1 and 300 m 2 /g, very advantageously between 1.5 and 200 m 2 /g.
• these fillers have an average aspect ratio greater than 3, advantageously greater than 7, very advantageously greater than 15.
• Scanning electron microscopy allows observation and visual appreciation of the morphology of compounds.
• Morphometry based on video acquisition and image analysis, provides access to quantifiable parameters characteristic of particle morphology.
• Alpaga 500 Nano apparatus for each tested sample, acquisitions are made on 10,000 particles and the elongation and blunting parameters are calculated for each particle.
• the thermally conductive filler has a density of less than 3 kg/L, advantageously less than 2.5 kg/L, very advantageously less than 2.3 kg/L. Density is measured according to ISO 787-10:1993.
• the thermally conductive filler is expanded graphite
• it is present in the composition according to the invention in a content of between 5 and 17% by weight relative to the total weight of the composition.
• the expanded graphite is the only thermally conductive filler in the composition.
• the thermally conductive filler When the thermally conductive filler is not expanded graphite, then it is present in the composition according to the invention in a content of between 5 and 35% by weight relative to the total weight of the composition. Preferably, when the thermally conductive filler is not expanded graphite, then it is present in the composition in a content of between 10 and 29.90%, preferably between 15% and 25%.
• composition according to the invention may comprise at least one additive.
• the additive can be chosen from a catalyst, an antioxidant, a heat stabilizer, a UV stabilizer, a light stabilizer, a lubricant, a flame retardant, a nucleating agent, a chain extender and a colorant.
• composition defined above further comprises additives chosen from antioxidants, UV stabilizers, heat stabilizers, plasticizers, nucleating agents, sticking agents, modifiers shocks, flame retardants, antistatic agents, reinforcing agents, lubricants, organic and inorganic fillers, optical brighteners, mold release agents, pigments, dyes, catalysts and mixtures thereof.
• additives chosen from antioxidants, UV stabilizers, heat stabilizers, plasticizers, nucleating agents, sticking agents, modifiers shocks, flame retardants, antistatic agents, reinforcing agents, lubricants, organic and inorganic fillers, optical brighteners, mold release agents, pigments, dyes, catalysts and mixtures thereof.
• the composition may comprise between 0 and 10% by weight of additives relative to the total weight of the composition, preferably between 0.1 and 5% of additive.
• composition comprises less than 20%, very advantageously less than 10%, preferably less than 5% of components having a density greater than 3.
• component is meant within the meaning of the present invention, any product present in the composition according to the invention regardless of its chemical nature. In other words, less than 20% of the fillers and additives possibly present in the composition must have a density greater than 3.
• the composition consists of the copolyamide as defined above as matrix, from 3 to 35% by weight relative to the total weight of the composition of at least one thermally conductive material, the carbon atom content of which is between 80 and 100%, and from 0 to 10% by weight of additives relative to the total weight of the composition, the composition comprising less than 20% of components having a higher density to 3 (measured according to ISO 787-10:1993).
• the melt viscosity of the composition is preferably between 0.5 and 400 Pa.s, advantageously between 2 and 200 Pa.s, very advantageously between 3 and 100 Pa.s.
• the melt viscosity is measured using a Brookfield rheometer using the SC 4-27 module according to the ASTM D3236-88 (2009) standard at 210°C.
• the composition according to the invention thus has a surface resistivity greater than 1010 Q.m, preferably greater than 1011 Q.m, measured according to standard IEC 62631-3-2 (2015).
• the composition is electrically insulating.
• the composition according to the invention preferably has an elongation at break (during ISO 527 tensile tests at 23° C.) greater than 10%, advantageously greater than 30%.
• the tensile modulus at 23° C. of the composition measured on test piece 1A (ISO 527) is preferably between 100 and 5000 MPa, advantageously between 200 and 4000 MPa, very advantageously between 200 and 800 MPa.
• the composition preferably has a dielectric constant (Dk) measured at 1 GHz preferably comprised between 2 and 6, advantageously from 2.5 to 4 and a dissipation factor (tan 5) comprised between 0.001 and 0.1, advantageously between 0.005 and 0.05.
• Dk dielectric constant
• titanium 5 dissipation factor
• the dielectric constant and the dissipation factor are measured according to the ASTM D150 standard on a 100*100*2 mm plate at a frequency of 1 GHz.
• composition according to the invention has a thermal conductivity of between 0.9 W/m.K and 4 W/m.K, advantageously from 1 W/m.K to 3 W/m.K, measured according to standard ASTM D5930-17.
• the invention also relates to the encapsulation process using the composition according to the invention.
• the composition according to the invention is used to manufacture 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 melted composition according to the invention is injected into the mold up to a pressure of between 0.5 and 50 bar and possibly subjected to a holding pressure, c) the molding composition is left to solidify by cooling, d) the mold is opened, e) the injection molded parts are removed from the mould.
• the low pressure injection molding process generally operates in the range of 2 to 40 bar, the temperature being between 160 and 250°C.
• composition according to the invention is capable of being injected at low pressure, that is to say at a pressure of less than 100 bars, preferably less than 50 bars.
• the present invention relates to the use of the composition according to the invention as defined above for the encapsulation of electronic devices, also called overmolding or molding, preferably located under the engine cover of a vehicle or in medical devices.
• the present invention also relates to the use of the composition according to the invention as defined above for the manufacture of a hot-melt adhesive in the form of a veil, a film, granules, a filament, a grid or a powder.
• the melt viscosity of the composition is between 0.5 and 400 Pa.s, advantageously between 2 and 200 Pa.s, very advantageously between 3 and 100 Pa.s.
• the melt viscosity is measured using a Brookfield rheometer using the SC 4-27 module according to the ASTM D3236-88 (2009) standard at 210° C. for a powder.
• compositions were obtained by melt mixing the components described in Tables 1 and 2 below.
• compositions above were manufactured using a ZSK 18 mm twin-screw extruder (Coperion). The barrel temperature was set at 210°C and the screw speed was 280 rpm with a throughput of 8 kg/h. The compositions were then dried under reduced pressure at 80° C. in order to reach a moisture content of less than 0.04%.
• Polyamide designates a hot-melt adhesive polyamide composed of 31 mol% of C10 diacid, 19% of pripol® 1013, 25 mol% of piperazine, 6.6 mol% of Jeffamine® D 2000 and 18.4 mol% of ethylene diamine.
• the Tg of the polyamide is -22°C measured by DSC, and a viscosity of 9 Pa.s at 200°C measured according to standard ASTM D3236-88 (2009).
• polyamide A is 210/pip10/pip36/POP36, pip being piperazine, POP being Jeffamine® D2000.
• the nomenclature used to define polyamides is described in standard ISO 1874-1:1992 "Plastics - Materials polyamides (PA) for molding and extrusion - Part 1: Designation", in particular on page 3 (tables 1 and 2).
• Expanded graphite refers to graphite with the trade name Timrex® C Therm HD max with a density of less than 2.5 sold by Imerys
• Graphite refers to graphite under the trade name Timrex® M100 with a density of less than 2.5 sold by Imerys
• Polyamide A designates a hot-melt adhesive polyamide composed of 31 mol% of C10 diacid, 19% of pripol® 1013, 25 mol% of piperazine, 6.6 mol% of Jeffamine® D 2000 and 18.4 mol% of ethylene diamine.
• Polyamide B denotes a PA 6 having a melting point of 220°C and a melt viscosity measured according to standard ASTM D3236-88 (2009) of 325 Pa.s at 280°C.
• Graphite refers to graphite with the trade name Timrex® M100 with a density of less than 2.5 sold by Imerys
• Expanded graphite is sold by under the name C Therm® HD max with a density of less than 2.5 sold by Imerys
• thermo and electrical properties of these compositions were measured according to the following methods.
• the homogeneity of these compositions in the molten state was also evaluated.
• the thermal conductivity was measured at 23°C on 100*100*5 mm plates using the Neotim® FP2C machine fitted with a hot wire, following the ASTM D5930-17 standard.
• Granules of the compositions are placed in a test tube immersed in a silicone oil bath at 15° C. above the Tm of the copolyamide for 30 minutes. At the end of the 30 minutes, the tube is placed in ambient air until the composition solidifies. The tube is then broken to recover the composition.
• the sample is cut in two (upper part separated from the lower part of the tube) in order to estimate the densities at 23°C according to ISO 1182-1 of the upper and lower parts of the sample. If the difference in density is greater than 0.3, the sedimentation is considered too great.
• composition according to the invention makes it possible to encapsulate parts at low pressure using a melter.
• the composition according to the invention has good thermal conductivity making it possible to avoid overheating of electronic equipment while being electrically insulating, which makes it possible to avoid short circuits.
• Compositions 9 and 10 cannot be used in an overmolding process because of their excessive viscosities and melting points.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Polyamides (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)

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• 2021
  • 2021-10-14 FR FR2110897A patent/FR3128223B1/fr active Active
• 2022
  • 2022-10-13 WO PCT/FR2022/051931 patent/WO2023062325A1/fr not_active Ceased
  • 2022-10-13 CN CN202280069133.7A patent/CN118103474A/zh active Pending
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