Flame-retardant composition based on bio-based polycarbonate copolymer, for use in 3D printing

Abstract

The invention relates to a flame-retardant material composition for use in 3D printing, comprising or consisting of: - 35% to 79% by weight, relative to the total weight of the composition, of at least one bio-based polycarbonate copolymer, the bio-based polycarbonate copolymer comprising at least repeating units resulting from the polymerisation of the 1,4:3,6-dianhydrohexitol monomer and at least repeating units resulting from the polymerisation of a monomer of a dihydroxylated alicyclic component; - 10% to 20% by weight, relative to the total weight of the composition, of organic phosphorus-containing compound; - 10% to 15% by weight, relative to the total weight of the composition, of a zinc molybdate and magnesium silicate complex; - 0.1% to 15% by weight, relative to the total weight of the composition, of a carbonate; and - optionally 0.1% to 15%, relative to the total weight of the composition, of talc.

Description

[0001] Flame-retardant composition based on bio-sourced polycarbonate copolymer usable in 3D printing

[0002] TECHNICAL FIELD OF THE INVENTION

[0003]

[0001] The field of the invention is that of flame retardant materials.

[0004]

[0002] More specifically, the invention relates to a flame retardant material composition based on bio-sourced polycarbonate copolymer, 3D printable and complying with the EN45545 fire safety standard and its particular fire / smoke requirement HL2-R22 for applications in the railway industry. The invention also relates to a method for manufacturing a flame retardant material comprising the composition which is the subject of the present invention as well as a method for preparing a three-dimensional shaped product by means of 3D printing, from the flame retardant material composition which is the subject of the present invention.

[0005] STATE OF THE ART

[0006]

[0003] 3D printing, also called additive manufacturing, is a shaping process, intended to produce objects by adding layer by layer a material corresponding to the successive cuts of a 3D model. Additive manufacturing is seen as a key technology for the future of the railway sector because it allows for the design of custom parts and therefore effectively addresses issues related to the maintenance and supply of parts (P. Kingsland, “3D printing in the railway sector with Deutsche Bahn”, Railway Technology, May 5, 2019; “3D printing in the railway industry”, OMNI3D, September 24, 2020). 3D also makes it possible to move closer to the concept of a circular economy by improving the environmental footprint by reducing material and energy waste linked to complex assemblies and the manufacturing of parts.A recent analysis has highlighted that the integration of additive manufacturing can reduce production waste by 70 to 80% while time to market is significantly shortened by up to 90% (H. Everett, “3D printing contributes to wabtec's sustainability achievements”, 3D Printing Industry, October 27, 2020).

[0007]

[0004] Despite the growing interest in additive manufacturing, the use of 3D printing technologies is slow to be used within the railway sector, as illustrated by the case of SNCF. This observation can be explained by the lack of availability of materials that are printable, high-performance (compatible with current fire / smoke standards), and competitive. Indeed, few solutions exist and all those proposed are too expensive to allow routine adoption of 3D printing for spare parts, which leads to the need to explore the transformation of other materials with which the targeted performances are currently, given the state of available knowledge, not acquired.

[0008]

[0005] While the choice of these new materials is primarily driven by the level of technicality required (in particular the fireproofing performance essential for parts studied in the railway industry), the train of the future is also guided by the imperatives of the railway market: developing lighter trains, reducing their carbon footprint while saving energy for an eco-responsible industry, gaining competitiveness by improving the efficiency of maintenance and reducing its cost. On this last point, the challenges are firstly economic (because the immobilization of a train represents a very high cost per day) but above all ecological: the parts come from the four corners of the planet, ordered in excess numbers, stored in huge hangars and often manufactured from petroleum-sourced materials. In addition, sustainable development has become a key consideration in the industry regardless of the levels of the supply chain.Reducing waste and improving operational efficiency are actions that help us move closer to the concept of the circular economy, which aims to make the best use of resources in order to avoid waste.

[0009]

[0006] The majority of 3D printable bio-based solutions currently available on the market are related to the building, furniture and construction sectors, or in some cases the automotive, packaging, or even bioengineering and pharmaceutical industries. However, their use remains very limited compared to petro-source materials. In addition, for a material to be used in the railway industry, it must respect and meet the requirements set by very strict and global fire safety standards such as EN 45545 (AFNOR, Railway applications - Fire protection in railway vehicles - Part 2: Requirements for the fire behavior of materials and components. 2013; J.-M. Guillemot and Y. -H. Grunevald, “Composites in railway construction”, p. 19, 2000).Indeed, due to the high thermal stresses to which materials are subjected during their use, this regulation specifies the reaction to fire performance requirements of the materials used and aims to reduce the risk of fires and the possible consequences if such an accident were to occur. The 2020 version of the EN 45545 regulation is structured according to the vehicle and the part used. There are thus three risk levels ("Hazard Levels" in English terminology, noted "HL") with HL1, HL2 and HL3 (HL1 being the lowest level), while there are twenty-eight levels of requirements ("Requirements" in English terminology, noted "R") which are based on the location of the part and its application. Each level of requirement is defined by a series of fire scenarios. In addition to these fire / smoke requirements, certain parts present within the train are subject to high mechanical stresses.It is therefore important to combine mechanical performance and high fire protection.

[0010]

[0007] For example, requirement R22 at hazard level HL2 includes three fire scenarios to be validated. All the criteria to be achieved are summarized in Table 1 below:

[0011] [Table 1]

[0012]

[0013] Table 1: Fire performance to be achieved to meet the HL2-R22 requirement of standard EN 45545 year 2020.

[0014]

[0008] All the criteria to be achieved (summarized in Table 1) highlight technological challenges. We can therefore see that the EN45545 fire / smoke standard, adapted to the railway sector, requires the materials developed to meet criteria when exposed to certain very specific fire scenarios. These criteria include: a minimum oxygen limit index of 28% according to ISO 4589-2, a maximum optical density (D smax) less than 300 with a heat flux of 25 kW / m 2 in the presence of a pilot flame according to ISO 5659-2 and finally an ITCG toxicity index OR

[0015] ITCPNL less than 0.9 based on EN17084 according to method 1 or method 2, respectively. Only the combination and validation of these three results ensures compliance with the HL2-R22 fire / smoke requirement.

[0016]

[0009] For most industrial sectors, the design of new parts or the replacement of existing ones involves a development phase. This includes the selection of a material that meets the specifications. Among the wide range of materials available, thermoplastic polymer materials have many advantages. It is possible to mention their low density, their thermomechanical properties, which allow their use over a wide temperature range, or their ability to be shaped with complex shapes thanks to their viscous behavior in a molten environment. In the railway sector, compliance with the EN45545 standard ensures that parts have good fire resistance in order to ensure a high level of safety. However, the development of polymer materials for the railway industry is a real challenge given the poor fire properties of certain virgin polymers such as polyolefins.However, these materials have many advantages as listed above and the contribution of new functional properties, including high fire resistance, would allow their use in the railway sector.

[0017]

[0010] With a view to reducing dependence on fossil resources, it would be good if the material included a bio-sourced component. However, the introduction of materials from renewable resources must not be to the detriment of the sustainability of the materials. Taking this factor into account rules out so-called biodegradable polymers. Indeed, their sensitivity to external conditions, i.e. UV, humidity, temperature, would lead to a degradation of their fire and mechanical properties due to chain splitting and the reduction of their molecular mass.

[0018]

[0011] The implementation method also plays a role. When the shaping method is 3D printing, the designed part must retain its fire properties in order to comply with the EN45545 standard. However, the printing parameters can play a key role in the final properties. Dimensional accuracy and the prevention of warping are influenced by the implementation conditions such as, for example, the temperatures of the nozzles and plates of the 3D printing devices as well as by the environment. Indeed, a shaping temperature that is too low can lead to a lack of inter-layer adhesion, lower rigidity but also greater porosity.

[0019]

[0012] It would therefore be appropriate to find new compositions of 3D printable materials, the compounds of which have the lowest possible cost, and have a low reaction to fire while limiting the spread of fire and minimizing the opacity and toxicity of the smoke released to comply with the railway standard EN45545 and in particular the R22 requirement of the HL2 hazard level of said standard. Such compositions should advantageously be ecological. The fact that the material is 3D printable would provide a considerable advantage for the replacement of obsolete parts, in particular due to the short manufacturing times and the absence of specific molds or tools for the latter. This would also allow the production of small volumes and provide the opportunity to review the design of certain parts in the railway sector.

[0020] STATEMENT OF THE INVENTION

[0021]

[0013] To this end, according to a first aspect, the present invention relates to a flame-retardant material composition comprising or consisting of:

[0022] - 35% to 79% by weight of at least one bio-sourced polycarbonate copolymer relative to the total weight of the composition, said bio-sourced polycarbonate copolymer comprising at least repeating units resulting from the polymerization of the 1,4:3,6-dianhydrohexitol monomer and at least repeating units resulting from the polymerization of a monomer of a dihydroxylated alicyclic component.;

[0023] - 10% to 20% by weight of organic phosphorus compound relative to the total weight of the composition,

[0024] - 10% to 15% by weight of a zinc molybdate and magnesium silicate complex relative to the total weight of the composition,

[0025] - 0.1% to 15% by weight of a carbonate relative to the total weight of the composition, and,

[0026] - optionally 0.1% to 15% of talc relative to the total weight of the composition.

[0014] In the present invention, the term “alicyclic compound” means any compound comprising one or more cycles, said cycle(s) being without heteroatom and non-aromatic, saturated or unsaturated.

[0027]

[0015] The biosourced polycarbonate copolymer is a polymer with a very low oxygen index and evaluated at only 18%. Furthermore, the evaluation of the opacity of the fumes of this biosourced polycarbonate copolymer subjected to a flow of 25 kW / m 2 and in the presence of a pilot flame, revealed the presence of significant soot which resulted in an increase in the opacity of the fumes, i.e. a D smax much higher than 300. The technical solution that is the composition that is the subject of the present invention is based on the introduction of an organic phosphorus compound and more particularly an aluminum diethylphosphinate. This agent acting preferentially in condensed phase in the biosourced polycarbonate copolymer matrix leads to a strong increase in the oxygen index and can reach 28% for a loading rate of 15% by mass relative to the total weight of the composition. This is made possible by the production of a carbon source acting as a protective barrier to fire. However, its sole addition does not allow a reduction in the opacity of the fumes. Aluminum diethylphosphinate must therefore be combined with other flame retardant fillers. The addition of a smoke suppressant has thus been considered and more particularly via the introduction of a zinc molybdate / magnesium silicate complex.The role of smoke suppressant is fulfilled by the addition of this complex with a strong reduction in the opacity of the smoke while ensuring a high value of the limiting oxygen index, i.e. greater than 28%. However, the technical solution that is the composition that is the subject of the present invention is also based on the introduction of magnesium carbonate and / or silicate in addition to the zinc molybdate / magnesium silicate complex. Despite its action on the opacity of the smoke, its sole addition with the organic phosphorus compound does not make it possible to meet the HL2-R22 requirement of the EN45545 standard. Only the combined addition of organic phosphorus compound, a zinc molybdate / magnesium silicate complex, a carbonate and optionally magnesium silicate (talc) in the proportions indicated above makes it possible to address the technical problem. These compounds have a synergistic action and lead to a reduction in the opacity of the smoke.These fire-smoke performances are demonstrated by the composition having a minimum oxygen index (Ol) limit of 28% according to ISO 4589-2, a maximum optical density in the test chamber (D. s max) less than 300 according to ISO 5659-2 and a conventional toxicity index (ITCg) less than 0.9.

[0028]

[0016] The composition that is the subject of the present invention makes it possible to partially address the problem of materials derived from fossil resources by reducing dependence on these materials. Indeed, the composition is based on a matrix derived from renewable resources and more particularly the biosourced polycarbonate copolymer. The high modulus of elasticity of this matrix makes it possible to produce rigid parts and its amorphous nature makes it possible to more easily address the technical problem of 3D printability.

[0017] Indeed, a material comprising or consisting of the composition that is the subject of the present invention can be advantageously used for the manufacture of parts by 3D printing.As used herein, the term "3D printing" may be understood in the broadest sense as any process that constructs a three-dimensional (3D) object from a computer-aided design (CAD) model, from a scan or other information, or by 3D drawing or any other means to generate a specific 3D shape. Typically, but not necessarily, 3D printing is accomplished by successively adding material layer by layer, which may be referred to as additive manufacturing. 3D printing may be distinguished from casting processes, forging processes, milling processes, and conventional machining.

[0029]

[0018] Furthermore, the compounds used to produce the composition which is the subject of the present invention have an advantageously low cost compared to that of the compounds of the flame retardant compositions of the prior art.

[0030]

[0019] The biosourced polycarbonate copolymer used in the composition that is the subject of the present invention is particularly well suited for implementation by 3D printing. Indeed, it does not have a semi-crystalline phase, which makes it possible to limit the phenomena of shrinkage of the material and consequently of warping. Furthermore, it comprises a high glass transition temperature (preferably between 70°C and 170°C, preferably between 95 and 140°C), which makes it possible to have at room temperature a material in a glassy state and having a high modulus of elasticity. The combination of these elements makes it an element of choice for responding to the technical problem formulated above.

[0031]

[0020] To this end, the invention further relates to the use of said flame-retardant material composition above for 3D printing.

[0032]

[0021] In preferred embodiments of the present invention, the flame retardant material composition comprises:

[0033] - 40% to 70% by weight of at least one bio-sourced polycarbonate copolymer relative to the total weight of the composition;

[0034] - 10% to 15% by weight of organic phosphorus compound relative to the total weight of the composition,

[0035] - 10% to 15% by weight of a zinc molybdate and magnesium silicate complex relative to the total weight of the composition, - 2% to 10% by weight of a carbonate relative to the total weight of the composition, and,

[0036] - optionally 2% to 10% talc relative to the total weight of the composition.

[0037]

[0022] In preferred embodiments of the present invention, the flame retardant material composition comprises:

[0038] - 65% by weight of at least one bio-sourced polycarbonate copolymer relative to the total weight of the composition;

[0039] - 12.5% ​​by weight of organic phosphorus compound relative to the total weight of the composition,

[0040] - 12.5% ​​by weight of a zinc molybdate and magnesium silicate complex relative to the total weight of the composition,

[0041] - 5% by weight of a carbonate relative to the total weight of the composition, and,

[0042] - optionally 5% talc relative to the total weight of the composition.

[0043]

[0023] It is with these proportions of each of its compounds that the composition which is the subject of the present invention gives the material which comprises it or is made of it the best flame retardant property meeting the railway industry standard EN 45545 and particularly the HL2-R22 requirement level.

[0044]

[0024] In preferred embodiments of the present invention, the flame retardant material composition comprises:

[0045] - 70% by weight of at least one bio-sourced polycarbonate copolymer relative to the total weight of the composition;

[0046] - 12.5% ​​by weight of organic phosphorus compound relative to the total weight of the composition,

[0047] - 12.5% ​​by weight of a zinc molybdate and magnesium silicate complex relative to the total weight of the composition,

[0048] - 5% by weight of a carbonate relative to the total weight of the composition.

[0049]

[0025] With these proportions of each of its compounds, the composition which is the subject of the present invention gives the material which comprises it or is made of it a very good flame retardant property meeting the railway industry standard EN 45545 and particularly the HL2-R22 requirement level.

[0050]

[0026] In particular embodiments, the invention further meets the following characteristics, implemented separately or in each of their technically operative combinations.

[0027] In particular embodiments, 1,4:3,6-dianhydrohexitol is selected from 1,4:3,6-dianhydro-D-sorbitol (isosorbide), 1,4:3,6-dianhydro-D-mannitol (isomannide), and 1,4:3,6-dianhydro-L-id itol (isoidide). Preferably, 1,4:3,6-dianhydrohexitol is 1,4:3,6-dianhydro-D-sorbitol also called isosorbide.

[0051]

[0028] In particular embodiments of the present invention, the biosourced polycarbonate copolymer comprises a number of repeating units resulting from the polymerization of 1,4:3,6-dianhydrohexitol relative to its total number of repeating units greater than or equal to 20%, preferably greater than or equal to 30%, more preferably greater than or equal to 50%, more preferably greater than or equal to 60%.

[0052]

[0029] According to a particular embodiment, the dihydroxylated alicyclic compound comprises a cycle with 5 or 6 carbon atoms.

[0053]

[0030] Preferably, the dihydroxylated alicyclic compound comprises a number of carbon atoms less than or equal to 70, preferably less than or equal to 50, more preferably less than or equal to 30.

[0054]

[0031] According to a particular embodiment, said dihydroxylated alicyclic compound is chosen from a compound of general formula (I) HOCH2-R 1 - CH2OH and a compound of general formula (II) HC-R 2 -OH, in which R 1 and R 2 , represent a cycloalkyl group having from 4 to 20 carbon atoms or a cycloalkoxyl group having from 6 to 20 carbon atoms.

[0055]

[0032] In a particular embodiment, the dihydroxylated alicyclic compound is chosen from cyclohexanedimethanol (CHDM) and the isomers of cyclohexanedimethanol, and in particular 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol and 1,4-cyclohexanedimethanol; tricyclodecanemethanol, pentacyclopentadecanedimethanol, including the isomers of the latter; decalindimethanol, and tricyclotetradecanedimethanol, including the isomers of the latter, in particular 2,6-decalindimethanol, 1,5-decalindimethanol and 2,3-decalindimethanol; norbonanedimethanol, including the isomers of the latter, in particular 2,3-norbonanedimethanol, and 2,5-norbonanedimethanol; adamantanedimethanol, including isomers thereof, notably 1,3-adamantanedimethanol.

[0056]

[0033] In a particular embodiment, the dihydroxylated alicyclic compound is chosen from cyclohexanediol and isomers thereof, in particular 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-ethyl-1,4-cyclohexanediol; tricyclodecanediol and isomers thereof; decalindiol, tricyclotetradecanediol and isomers thereof, in particular 2,6-decalindiol, 1,5-decalindiol, and 2,3-decalindiol; norbornanediol and isomers thereof, such as 2,3-norbornanediol, and 2,5-norbornanediol; and adamantanediol and isomers thereof, such as 1,3-adamantanediol.

[0057]

[0034] In particular embodiments of the present invention, the biosourced polycarbonate copolymer comprises a number of repeating units resulting from the polymerization of the dihydroxylated alicyclic compound relative to its total number of repeating units less than or equal to 60%, preferably less than or equal to 50%, more preferably less than or equal to 40%.

[0058]

[0035] In particular embodiments of the present invention, the bio-sourced portion of the bio-sourced polycarbonate copolymer is between 15% and 100%, preferably between 25% and 90%, preferentially between 55% and 75%. According to a preferred embodiment, the bio-sourced portion of the polycarbonate is 56%.

[0059]

[0036] In particular embodiments of the present invention, the carbonate is calcium carbonate.

[0060]

[0037] In particular embodiments of the present invention, the organic phosphorus compound is selected from phosphonates, phosphinates, phosphites, phosphazenes and a mixture of two or more of these. Preferably, said organic phosphorus compound is selected from alkylphosphinates. Preferably, said organic phosphorus compound is selected from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-melamine also known as dopo-melamine and aluminum diethylphosphinate. More preferably, said organic phosphorus compound is aluminum diethylphosphinate. The latter makes it possible to obtain the best flame retardant results.

[0061]

[0038] In a preferred embodiment of the present invention, the flame retardant material composition comprises:

[0062] - 65% by weight of at least one bio-sourced polycarbonate copolymer relative to the total weight of the composition; - 12.5% ​​by weight of aluminum diethylphosphinate relative to the total weight of the composition,

[0063] - 12.5% ​​by weight of a zinc molybdate and magnesium silicate complex relative to the total weight of the composition,

[0064] - 5% by weight of calcium carbonate relative to the total weight of the composition, and,

[0065] - optionally 5% talc relative to the total weight of the composition.

[0066]

[0039] In a preferred embodiment of the present invention, the flame retardant material composition comprises:

[0067] - 70% by weight of at least one bio-sourced polycarbonate copolymer relative to the total weight of the composition;

[0068] - 12.5% ​​by weight of aluminum diethylphosphinate relative to the total weight of the composition,

[0069] - 12.5% ​​by weight of a zinc molybdate and magnesium silicate complex relative to the total weight of the composition,

[0070] - 5% by weight of calcium carbonate relative to the total weight of the composition.

[0071]

[0040] In particular embodiments of the present invention, the flame retardant material composition comprises at least one polymeric additive selected from stabilizers, antioxidants, colorants, pigments, mold release agents, plasticizers, treatment agents, antimicrobial agents, slip agents, antistatics, conductive additives, insulating additives, anti-drip agents, other flame retardants, and combinations of two or more thereof. Preferably, said at least one polymeric additive is present in the composition at a level of 0.1% to 10% by weight, preferably 0.1% to 5% by weight, relative to the total weight of the composition.

[0072]

[0041] In particular embodiments of the present invention, the flame retardant material composition comprises at least one reinforcing agent. Such a reinforcing agent is preferably included in the composition at a level of 0.1% to 10% by weight, preferably 0.1% to 5% by weight, relative to the total weight of the composition. Preferably, the reinforcing agent is chosen from glass fiber, carbon fiber, aramid fiber, basalt fiber, flax fiber, cellulose fiber, jute fiber and a mixture of at least two of these.

[0042] According to a second aspect, the present invention relates to a 3D printing powder, a 3D printing granule or a 3D printing filament, comprising or consisting of the flame retardant material composition which is the subject of the present invention.

[0073]

[0043] According to a third aspect, the present invention relates to the use of a composition which is the subject of the present invention, of a 3D printing powder, of a 3D printing granule or of a 3D printing filament which is the subject of the present invention, for 3D printing.

[0074]

[0044] According to a fourth aspect, the present invention relates to a part intended for the railway industry comprising or consisting of the flame-retardant material composition which is the subject of the present invention.

[0075]

[0045] According to a fifth aspect, the present invention relates to a means of rail transport comprising a part comprising or consisting of the flame-retardant material composition which is the subject of the present invention. Such a means of rail transport is, for example, a train.

[0076]

[0046] According to a sixth aspect, the present invention relates to a method for manufacturing a flame-retardant material comprising or strictly consisting of the composition which is the subject of the present invention, said method comprising the following steps of:

[0077] - heating of the bio-sourced polycarbonate copolymer;

[0078] - adding to the heated biosourced polycarbonate copolymer said at least one organic phosphorus compound, said zinc molybdate and magnesium silicate complex, said at least one carbonate and optionally talc, so as to obtain the flame retardant material composition which is the subject of the present invention, the biosourced polycarbonate copolymer being present in the composition at a level of 35% to 79% by weight relative to the total weight of the composition, the organic phosphorus compound at 10% to 20% by weight relative to the total weight of the composition, the zinc molybdate and magnesium silicate complex at 10% to 15% by weight relative to the total weight of the composition, the carbonate at 0.1% to 15% by weight relative to the total weight of the composition and the talc at 0.1% to 15% by weight relative to the total weight of the composition;

[0079] - mixing of the flame retardant material composition;

[0080] - cooling said composition so as to obtain the flame retardant material.

[0047] According to particular embodiments of the present invention, the method for manufacturing a flame retardant material which is the subject of the present invention comprises an additional step of cutting the cooled composition into granules so as to obtain the flame retardant material in the form of granules. Such an operation can be carried out for example in a granulator or a grinder.

[0081]

[0048] In particular embodiments of the present invention, the step of heating the biosourced polycarbonate copolymer is carried out at a temperature between 90°C and 260°C, preferably between 200°C and 250°C.

[0082]

[0049] In particular embodiments of the present invention, during the step of heating the bio-sourced polycarbonate copolymer, said heating is carried out gradually. Preferably, the heating step is carried out in parallel with a mixture of the bio-sourced polycarbonate copolymer, for example by shearing.

[0083]

[0050] In particular embodiments of the present invention, the step of cooling the composition is carried out at room temperature.

[0084]

[0051] In particular embodiments of the present invention, the steps of heating, adding to the heated polycarbonate said at least one organic phosphorus compound, said zinc molybdate and magnesium silicate complex, said at least one carbonate and optionally talc, and mixing, are carried out with an extruder.

[0085]

[0052] According to a seventh aspect, the present invention relates to a method for preparing a three-dimensional shaped product by means of 3D printing, injection, thermoforming or thermocompression from the flame-retardant material composition which is the subject of the present invention.

[0086]

[0053] The present invention particularly relates to a method for preparing a product of three-dimensional shape by means of 3D printing, said method comprising the steps, preferably successive, of:

[0087] - provision of a flame retardant material composition which is the subject of the present invention;

[0088] - heating defined portions of the flame retardant material composition above the glass transition temperature of said composition;

[0089] - preparing the three-dimensional shaped product from the heated flame retardant material composition; - cooling the heated flame retardant material composition to obtain the solid three-dimensional shaped product.

[0090]

[0054] According to embodiments of the method for preparing a three-dimensional shaped product by means of 3D printing, the step of preparing the three-dimensional shaped product from the heated flame-retardant material composition involves depositing successive layers of the heated flame-retardant material composition on a support.

[0091]

[0055] According to embodiments of the method for preparing a three-dimensional shaped product by means of 3D printing, the step of heating the defined parts of the flame-retardant material composition is preferably carried out at a temperature of between 190°C and 290°C, between 200°C and 280°C, between 210°C and 270°C, between 220°C and 260°C, between 230°C and 255°C, preferably at 250°C.

[0092]

[0056] According to embodiments of the method for preparing a three-dimensional shaped product by means of 3D printing, the cooling step can be carried out at a temperature between room temperature which is approximately 20°C and 120°C, preferably between 20°C and 110°C, between 30°C and 90°C, between 40°C and 100°C, between 60°C and 100°C, between 70°C and 90°C or between 70 and 80°C. Preferably, the cooling step is carried out at room temperature which is approximately 20°C or at a temperature below room temperature.

[0093]

[0057] According to one embodiment of the method for preparing a three-dimensional shaped product by means of 3D printing, the flame retardant material composition is replaced by a 3D printing powder, a 3D printing granule or a 3D printing filament, comprising or consisting of the flame retardant material composition.

[0094] BRIEF DESCRIPTION OF THE FIGURES

[0095]

[0058] Other advantages, aims and particular characteristics of the present invention will emerge from the following non-limiting description of at least one particular embodiment of the compositions and processes which are the subject of the present invention, with reference to the appended drawing, in which:

[0096] - [Fig. 1] Figure 1 is a schematic view of a twin-screw extruder (Haake® Rheomex OS PTW16, “Thermo Scientific” (Waltham, Massachusetts, United States of America)) for implementing the method of manufacturing the flame-retardant material comprising the composition which is the subject of the present invention.

[0097] DETAILED DESCRIPTION OF THE INVENTION

[0098]

[0059] The present description is given as a non-limiting example of embodiment.

[0099]

[0060] As a reminder, the present invention relates to a flame-retardant material composition comprising:

[0100] - 35% to 79% by weight of at least one bio-sourced polycarbonate copolymer relative to the total weight of the composition, said bio-sourced polycarbonate copolymer comprising at least repeating units resulting from the polymerization of the 1,4:3,6-dianhydrohexitol monomer and at least repeating units resulting from the polymerization of a monomer of a dihydroxylated alicyclic component;

[0101] - 10% to 20% by weight of organic phosphorus compound relative to the total weight of the composition,

[0102] - 10% to 15% by weight of a zinc molybdate and magnesium silicate complex relative to the total weight of the composition,

[0103] - 0.1% to 15% by weight of a carbonate relative to the total weight of the composition, and,

[0104] - optionally 0.1% to 15% of talc relative to the total weight of the composition.

[0061] 1,4:3,6-dianhydrohexitol is preferably chosen from 1,4:3,6-dianhydro-D-sorbitol (isosorbide), 1,4:3,6-dianhydro-D-mannitol (isomannide), and 1,4:3,6-dianhydro-L-iditol (isoidide). Preferably, 1,4:3,6-dianhydrohexitol is 1,4:3,6-dianhydro-D-sorbitol also called isosorbide.

[0105]

[0062] The dihydroxylated alicyclic compound is preferably chosen from a compound of general formula (I) HOCH2-R 1 -CH2OH and a compound of general formula (II) HC-R 2 -OH, in which R 1 and R 2 , represent a cycloalkyl group having from 4 to 20 carbon atoms or a cycloalkoxyl group having from 6 to 20 carbon atoms.

[0106]

[0063] Preferably, the dihydroxylated alicyclic compound is chosen from cyclohexanedimethanol (CHDM) and cyclohexanedimethanol isomers, and in particular 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol and 1,4-cyclohexanedimethanol; tricyclodecanemethanol, pentacyclopentadecanedimethanol, including isomers thereof; decalindimethanol, and tricyclotetradecanedimethanol, including isomers thereof, in particular 2,6-decalindimethanol, 1,5-decalindimethanol and 2,3-decalindimethanol; norbonanedimethanol, including isomers thereof, in particular 2,3-norbonanedimethanol, and 2,5-norbonanedimethanol; adamantanedimethanol, including isomers thereof, notably 1,3-adamantanedimethanol.

[0107]

[0064] Preferably, the dihydroxylated alicyclic compound is chosen from cyclohexanediol and the isomers thereof, in particular 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-ethyl-1,4-cyclohexanediol; tricyclodecanediol and the isomers thereof; decalindiol, tricyclotetradecanediol and the isomers thereof, in particular 2,6-decalindiol, 1,5-decalindiol, and 2,3-decalindiol; norbornanediol and the isomers thereof, such as 2,3-norbornanediol, and 2,5-norbornanediol; and adamantanediol and isomers thereof, such as 1,3-adamantanediol.

[0108]

[0065] One of the biosourced polycarbonate copolymers preferred for producing the composition which is the subject of the present invention is, for example, poly(isosorbide carbonate-co-1,4-cyclohexanedimethanol).

[0109]

[0066] Organic phosphorus compounds that can be used for producing the composition that is the subject of the present invention are, for example, phosphonates, phosphinates, phosphites, phosphazenes and a mixture thereof. Preferably, said organic phosphorus compound is chosen from alkylphosphinates. Preferably, said organic phosphorus compound is chosen from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-melamine (dopo-melamine) and aluminum diethylphosphinate (for example Exolit® OP 1230 marketed by the company “Clariant”). Another example is dimethyl methyl phosphonate (DMMP). Aluminum diethylphosphinate remains the preferred organic phosphorus compound.

[0110]

[0067] Carbonates that can be used to produce the composition that is the subject of the present invention are preferably chosen from calcium carbonates, magnesium carbonates, sodium carbonates, potassium carbonates and zinc carbonates. Preferably, calcium carbonate is used as carbonate of the composition that is the subject of the present invention.

[0068] The present invention also relates to a method for manufacturing a flame-retardant material comprising or consisting strictly of the composition that is the subject of the present invention, said method comprising the following steps:

[0111] - heating of the bio-sourced polycarbonate copolymer;

[0112] - adding to the heated biosourced polycarbonate copolymer said at least one organic phosphorus compound, said zinc molybdate and magnesium silicate complex, said at least one carbonate and optionally talc, so as to obtain the flame retardant material composition which is the subject of the present invention, the biosourced polycarbonate copolymer being present in the composition at a level of 35% to 79% by weight relative to the total weight of the composition, the organic phosphorus compound at 10% to 20% by weight relative to the total weight of the composition, the zinc molybdate and magnesium silicate complex at 10% to 15% by weight relative to the total weight of the composition, the carbonate at 0.1% to 15% by weight relative to the total weight of the composition and the talc at 0.1% to 15% by weight relative to the total weight of the composition;

[0113] - mixing of the flame retardant material composition;

[0114] - cooling said composition so as to obtain the flame retardant material.

[0069] A. Example of a method for manufacturing a flame retardant material comprising a composition which is the subject of the present invention:

[0115]

[0070] A.1 Compounds

[0116]

[0071] A copolymer matrix of the biosourced polycarbonate type derived from isosorbide was chosen as part of the technical solution. This is a biosourced polycarbonate copolymer according to the invention in which the 1,4:3,6-dianhydrohexitol is 1,4:3,6-dianhydro-D-sorbitol. More precisely, it is poly(isosorbide carbonate-co-1,4-cyclohexanedimethanol). The trade name of the biosourced polycarbonate copolymer used is DURABIO® D7340 (“MCPP”, Tokyo, Japan) and contains a biosourced portion of 56%. This biosourced polycarbonate copolymer is used for the manufacture of the flame-retardant material which is the subject of the present invention.

[0117]

[0072] Aluminum diethylphosphinate (Exolit® OP1230 marketed by "Clariant") is used as an organic phosphorus compound. A zinc molybdate and magnesium silicate complex marketed under the name Kemgard® 911 C by "Huber Materials" is used (it contains magnesium silicate, molybdenum zinc oxide and crystalline silicas and quartz which are impurities). Calcium carbonate (Millicarb® OG marketed by "Omya") is used as a carbonate. JETFINE® 3CA talc marketed by "Imerys" is also used. All the compounds of the developed flame retardant material composition, as well as their mass percentage and role are summarized in the

[0118] Table 2 below.

[0119] [Table 2]

[0120] Table 2: Example of composition of the flame retardant material

[0073] This flame retardant material composition is the composition implemented by the inventors having the best results in the fire / smoke performance tests so as to meet the HL2-R22 requirement criteria of the railway standard EN45545.

[0074] A.2 Extrusion manufacturing process

[0075] A twin-screw extruder (Haake® Rheomex OS PTW16, “Thermo Scientific” (Waltham, Massachusetts, United States of America)), with a screw diameter of 16 mm and a length to diameter ratio of 40 / 16 L / D, is used to formulate the flame retardant material. This extruder 100 consists of ten heating zones, set to the following temperature profile: Ti: 260°C - T2: 260°C - T3: 260°C - T4: 240°C - Ts: 220°C - Te: 220°C - T7: 220°C - Ts: 220°C - T9: 220°C - T10: 220°C, from a feed zone 101 of bio-sourced polycarbonate copolymer derived from isosorbide (PC) to an outlet die 102 of the flame-retardant material (figure 1).The compounds other than the copolymer are introduced into the zones which are at temperature Ts and Te, by means of a gravimetric doser 103. The speed of the extruder screw is 200 rpm. At the extrusion outlet, a rod 104 of flame-retardant polymer material is obtained and the latter is cooled in air to ambient temperature and then cut into granules 105 by means of a granulator or grinder 106 (“Thermo Scientific” (Waltham, Massachusetts, United States of America)). The granules can then be used to produce a product 107 by 3D printing, thermocompression or injection for example.

[0121]

[0076] A.3 Formatting

[0122]

[0077] From the granules of the fireproof material, plates of standardized dimensions and dependent on the fire scenarios considered (10x100xe mm 3for the measurement of the limiting oxygen index, where e represents the thickness of the sample and may vary depending on the thickness to be certified; 75 x 75 mm 2 with variable thickness for the measurement of D s max), were produced by thermocompression using a “Fontijne” press (“Fontijne Grotnes BV”, Niles, Michigan, USA) or 3D printing (pellet additive manufacturing (PAM) technique, with the “Tool Changer” printer supplied by “E3D”).

[0123]

[0078] B. Study of the fire / smoke performance of the flame retardant material

[0124]

[0079] As explained in the preceding paragraphs, the technical solution is based on the simultaneous mixing of three fillers or optionally four in a matrix of biosourced polycarbonate copolymer derived from isosorbide. These fillers are aluminum diethylphosphinate (marketed under the name Exolit® OP1230), a zinc molybdate / magnesium silicate complex (commercially sold under the name kemgard® 911), calcium carbonate and optionally magnesium silicate (talc). The combination of these different fillers makes it possible to meet the criteria of the HL2-R22 requirement defined in the EN45545 standard and whose fire performances for a thickness of 2 mm, 3 mm and 6 mm are given in Table 3 below.

[0125] [Table 3]

[0126] Table 3: Summary of fire performance for the flame-retardant material composition according to the invention obtained by thermocompression on samples with a thickness of 3 mm and by 3D printing on samples with a thickness of 2 mm, 3 mm and 6 mm.

[0127]

[0080] The biosourced polycarbonate copolymer derived from isosorbide is a copolymer exhibiting very low fire-smoke performance and in particular a low limiting oxygen index, i.e. 18%. When a sample is subjected to the impact of a flame, a strong dripping phenomenon is present. The composition which is the subject of the present invention with or without the presence of talc shows a high limiting oxygen index and reaches a value of 30 and 29% respectively for a thickness of 3 mm. Taking mechanical properties into account in a specification is an important point when developing an industrial part. However, the inclusion of fillers in a matrix tends to reduce mechanical performance due to the low compatibility between the fillers and the matrix. Minimizing the overall filler content is thus a lever for improving these properties.The technical solution that is the composition that is the subject of the present invention optionally proposes the inclusion of magnesium silicate in order to increase the oxygen index and reach 30%. Said composition, when subjected to the impact of a flame, develops a carbon source (also called "char") and allows flame retardancy of the biosourced polycarbonate copolymer matrix.

[0128]

[0081] Compliance with the HL2-R22 requirement is also conditioned by low smoke opacity characterized by the D s , max. This index is obtained through a smoke chamber based on ISO 5659-2. The composition object of the present invention with or without the presence of magnesium silicate, a carbon source is generated through the intumescent system which acts as a protective barrier. The flame retardant composition object of the present invention makes it possible to obtain an index Ds max less than 300.

[0129]

[0082] Finally, the toxicity of the fumes was evaluated using EN 17084 and the smoke chamber test. The ITCg value obtained for the composition which is the subject of the present invention comprising magnesium silicate is very much lower than the maximum value required by the HL2-R22 requirement with an ITCg value at 4 and 8 minutes of less than 0.9. The toxicity of the technical solution without the magnesium silicate also gives an ITCg value at 4 and 8 minutes of less than 0.9.

[0130]

[0083] In summary, the technical solution is obtained by introducing aluminum diethylphosphinate at a level of 12.5%, a zinc molybdate and magnesium silicate complex at a level of 12.5%, calcium carbonate with or without the presence of talc at a respective level of 5%, in a biosourced polycarbonate copolymer type matrix. The fire performances evaluated on samples with a thickness of 3 mm obtained by thermocompression make it possible to meet the HL2-R22 fire / smoke requirement with values ​​of LOI, D smax and ITCg in accordance with the required thresholds of the HL2-R22 requirement. The same applies to the fire performance evaluated on samples with a thickness of 2 mm obtained by 3D printing which meets the HL2-R22 requirement despite the change in shaping process. The composition which is the subject of the present invention therefore makes it possible to respond to the technical problem formulated with the development of a bio-sourced polymer material, potentially 3D printable and meeting the HL2-R22 fire / smoke requirement of the EN45545 standard.

[0131]

[0084] C. Comparative tests

[0132]

[0085] Multiple formulations were developed (by extrusion) and tested according to different fire scenarios defined by the requirements of EN 45545. The assessment of smoke opacity was carried out in a closed enclosure whose design, testing and data processing are based on ISO 5956-2. The toxicity assessment is based on EN 17084 for the determination of ITCg and the tests are carried out in the smoke enclosure (ISO 5659-2) where the gas analysis is carried out using the Fourier Transform Infrared Spectroscopy (FTIR) gas analysis technique. As for the determination of the oxygen index, the apparatus and operating conditions used comply with ISO 4589-2.The strategy implemented consisted, as mentioned previously, of evaluating the flame retardant performance of the materials developed in order to determine whether these materials meet the various HL2-R22 requirements of the railway standard EN45545.

[0133]

[0086] The chosen bio-sourced polycarbonate copolymer is derived from isosorbide and is marketed by the company "MITSUBISHI" under the name DURABIO® D7340. This was chosen because it is currently the only one commercially available. More particularly, DURABIO® D7340 was chosen because it has the highest rate of bio-sourced material in its composition, up to 56%. Unlike its petroleum-sourced counterpart, the evaluation and improvement of its performance has never been explored. It is known that petro-sourced polycarbonate is a self-intumescent matrix which has, as measured, a limiting oxygen index of 25% (Polycarbonate CALIBRE® 302 TINT, “Trinseo”). Its flame retardancy can be achieved in particular by the introduction of resorcinol bis (diphenyl phosphate) (RDP), triphenyl phosphate (TPP) or by the introduction of polyhedral oligomeric silsesquioxane (POSS).A comparison between the oxygen index values ​​of the bio-based and petro-based polycarbonate copolymer reveals a much lower value for the bio-based grade. Indeed, an oxygen index of only 18% (DURABIO® D7340, MCPP) was measured compared to 25% for the petro-based polycarbonate copolymer. This difference can be explained by the absence of development of a carbon source. Unlike the bio-based grade, the petro-based polycarbonate copolymer develops a char. This major difference implies that the behavior upon impact of a flame differs between these two types of polycarbonate copolymer and that the chemical structure plays a key role in fire performance.

[0134]

[0087] In order to improve the fire performance of the bio-sourced polycarbonate copolymer, the addition of additives in the molten medium was carried out. The evaluation of the fire performance first focused on the limiting oxygen index (ISO 4589-2). This makes it possible to discriminate between the compositions and thus select those which are the most efficient before evaluating the opacity of their smoke. All the tests presented were carried out on thermo-compressed samples with a thickness of 3 mm. The objective is to accelerate development times to make a faster screening, before defining and determining the 3D printing profile of the chosen formulation.

[0135]

[0088] A multitude of compositions were therefore tested and formulated by adding various additives within the biosourced polycarbonate copolymer matrix using a twin-screw extruder (previously described in section 3.2.). The first works focused on the addition of different types of additives acting in the gas phase and in the condensed phase, the formulations of which are detailed in Table 4. A selection of flame retardant fillers was therefore made. It should be noted that the processing temperatures are relatively high and that the selection of additives must be made accordingly.

[0136]

[0089] Thus, the degradation temperature of the additives must be higher than the implementation temperature. The additives used therefore have a degradation temperature higher than 250°C, which restricts the selection and possible interactions.

[0137] [Table 4]

[0138] Table 4: Oxygen index of flame-retardant compositions made from bio-sourced polycarbonate copolymer (PC) with a thickness of 3 mm (NC = Not Compliant with the HL2-R22 standard).

[0139]

[0090] The introduction of the selected flame retardant fillers shows a very slight improvement in the oxygen index (Table 4). Indeed, this index increases to a value of only 22% and therefore well below the prerequisite of the HL2-R22 requirement, i.e. 28%. It should be noted that during the test according to ISO 4589-2, the samples containing POSS and / or TPP show strong dripping. This dripping being greater than 50 mm from the top of the sample, the result is therefore negative.

[0140]

[0091] With this in mind, the preferred strategy is to introduce one or more flame retardants acting in the condensed phase in order to generate a carbon source and thus limit this dripping. The introduction of magnesium hydroxide (MDH) and / or magnesium carbonate (MgCOs) makes it possible to generate a small carbon source with loading rates of 30-40% and 10%, respectively. Despite the presence of this carbon source, the improvement in the oxygen index remains limited and several corrective strategies can be adopted such as (i) increasing the loading rate, (ii) adding a synergistic agent or (iii) adding an agent in the gas phase.

[0141]

[0092] However, when developing the composition, it is important not to alter the mechanical properties of the material and limit the cost of the raw material to be economically profitable. Therefore, the loading rate for MDH and MgCOs must be limited. Indeed, compositions comprising MDH show great fragility when mechanically stressed by hand. Conversely, when adding MgCOs, the biosourced polycarbonate copolymer retains its high rigidity. However, MgCOs does not show a positive contribution to the oxygen index value.

[0142]

[0093] The results obtained show that the flame retardancy strategy of the bio-sourced polycarbonate copolymer is very different from that of the petro-sourced polycarbonate copolymer and that the use of new PC / additive combinations is required. Based on the results obtained, the simultaneous introduction of TPP and MgCOs was explored in order to have both a gas phase action (TPP) and a condensed phase action (MgCOs) with a 50 / 50 ratio. Despite this, no improvement in the oxygen index was observed. Furthermore, a second flame retardancy strategy was retained with the introduction of aluminum diethyl-phosphinate (Exolit® OP1230, “Clariant”).

[0143]

[0094] C.1 Addition of an organic phosphorus compound

[0144]

[0095] This second strategy with the introduction of OP1230 into the PC matrix at different rates, i.e. 10%, 15% and 20%, makes it possible to significantly increase the oxygen index up to a value of 28% for a thickness of 3 mm and a rate of 15% of OP1230. The introduction of this charge makes it possible to generate a carbon source. OP1230 decomposes both in the gas phase with the formation of phosphonic acid and ethylene and in the condensed phase by the production of aluminum phosphates. According to the observation of the samples, OP1230 would have a privileged contribution in the condensed phase when mixed with the biosourced polycarbonate copolymer, allowing the generation of a carbon source. This acts as a protective barrier to fire and makes it possible to significantly increase the oxygen index. A maximum value is reached for a load rate of 15% while beyond this, a threshold is reached.However, and as given in Table 5, the smoke opacity which is evaluated by means of the Ds.max index is very clearly higher than the threshold defined by the HL2-R22 requirement, i.e. value of 300. It is therefore appropriate to add additional additives in order to reduce this smoke opacity without reducing the limit oxygen index value.

[0145]

[0096] C.2 Addition of a carbonate

[0146]

[0097] The introduction of calcium carbonate (CaCOs) in combination with OP1230 with an overall loading rate of 20% was studied. The ratio between these two loadings can have an impact on fire performance. Indeed, an OP1230:CaCO3 ratio of 1:1 leads to a degradation of the oxygen index with a decrease in its value, i.e. a reduction of 2%. Conversely, a 3:1 ratio, i.e. a content of 5% CaCOs for 15% OP1230, makes it possible to achieve an oxygen index of 30% (Table 5). It is noted that a carbon source develops when the sample is subjected to the impact of a flame. Achieving this value thus makes it possible to comply with the first fire scenario of the HL2-R22 requirement corresponding to an oxygen index of at least 28%.According to the results obtained, the addition of calcium carbonate in combination with aluminum diethylphosphinate makes it possible to strengthen the carbon source produced and thus improve the effectiveness of the protective barrier to fire.

[0147]

[0098] However, the effectiveness of this barrier does not allow the opacity of the fumes to be drastically reduced. Indeed, the evaluation of the index D s max according to ISO 5659 on the formulation PC + 15% OP1230 + 5% CaCOs shows that the opacity is above the prerequisite of the HL2-R22 requirement. The ITCg values ​​at 4 and 8 minutes are in accordance with the requirement of TEN45545 (version 2020). The introduction of new fillers was thus studied in order to reduce the opacity of the fumes.

[0099] C.3 Addition of the zinc molybdate / magnesium silicate complex

[0148]

[0100] Kemgard® 911 C is a product marketed by Huber Materials and used for its smoke suppressant properties specifically in Polyvinyl Chloride (PVC). Kemgard® 911 C is a complex of magnesium silicate and zinc molybdate. This flame retardant was introduced at different contents in the presence of one, two or more flame retardants into the bio-sourced polycarbonate (PC) copolymer matrix, i.e. Exolit® OP1230, Exolit® OP1230 / CaCO3 or Exolit® OP1230 / CaCO3 / Talc.

[0149]

[0101] The results obtained show that the addition of Kemgard® 911 C has a positive contribution in reducing the smoke density of the biosourced polycarbonate copolymer. It has indeed been shown that the addition of this additive in the matrix in the presence of Exolit® OP1230 allows a very significant reduction in the opacity of the smoke by significantly reducing the Ds.max index. However, the value reached for the formulation PC + 12.5% ​​OP1230 + 12.5% ​​Kemgard® 911 C remains above the threshold value defined for the HL2-R22 requirement (Table 5).

[0150]

[0102] Other formulations have thus been tested in order to reduce the opacity of the fumes while maintaining a high level of limiting oxygen index. Thus, the addition of Kemgard® 911 C in the PC + OP1230 / CaCO3 mixture has been explored and leads to a drastic reduction in the D value. s max (Table 5). Increasing its content tends to decrease the opacity of the fumes with a lowering of the D value smax. Thus, the combination of the organic phosphorus compound, carbonate and zinc molybdate / magnesium silicate complex makes it possible to meet the HL2-R22 requirement according to an optimal ratio between the fillers. In this optimization, taking into account i) the minimization of the overall filler rate and ii) printability tends to explore several ratios between the fillers. It has thus been shown that increasing the Exolit® OP1230 content has a negative effect on smoke opacity by increasing the value of Ds, max as observed between the compositions PC + 15% OP1230 + 5% CaCO3+ 12.5% ​​Kemgard® 911 C and PC + 12.5% ​​OP1230 + 5% CaCO3+ 12.5% ​​Kemgard® 911 C. A modulation of the fire performance can be obtained by varying the content of the OP1230 and Kemgard® 911 C fillers and the overall filler rate.

[0151]

[0103] C .4 Possible addition of talc

[0152]

[0104] The addition of a fourth flame retardant agent, i.e. magnesium silicate (talc), in the OP1230 / CaCO3 / Kemgard® 911 C mixture was also explored and the results are given in Table 5. The fire performances obtained show that the addition of talc also makes it possible to meet the HL2-R22 requirement of the EN45545 standard.

[0153] [Table 5]

[0154]

[0105] Table 5: Compositions tested

[0106] D. Means of measuring the different parameters

[0155]

[0107] In the context of the invention, that is to say a composition meeting the HL2-R22 fire / smoke requirements, three measuring instruments are required.

[0156]

[0108] D 1. Measurement of the limiting oxygen index

[0157]

[0109] A limiting oxygen index measuring device is a measuring device for determining the minimum oxygen concentration. This test is based on ISO 4589-2. To carry out this test, specimens with dimensions of 100x10xe mm 3 are used where e represents the thickness of the sample and can vary depending on the thickness to be certified.

[0158]

[0110] D2. Measurement of the index D s max

[0159]

[0111] To measure the index D s max, we use a test chamber with a volume of 0.5 m 3 where the sample is exposed to a cone-shaped resistance in a horizontal position. A device is set up to measure the smoke density as a function of time and to obtain the optical density. This test is based on ISO 5659-2. To carry out this test, specimens with dimensions of 75x75 mm are used. 2with variable thickness are used. Within the framework of the fire / smoke requirement HL2-R22, the test is carried out with a heat flux of 25 kW / m 2 and in the presence of a pilot flame. The evaluation of smoke production and its opacity is evaluated according to a value of Ds max and defined according to the following equation according to the ISO 5659-2 standard:

[0160] [Math. 1] where Tmin is the measured transmission.

[0161]

[0112] D3. Measurement of smoke toxicity

[0162]

[0113] According to the HL2-R22 requirement it is possible to determine the toxicity of fumes using two methods following EN17084. The first method is done using a smoke chamber whose apparatus is specified in ISO 5659-2. The gas analysis is done using Fourier Transform Infrared Spectroscopy (FTIR). This allows to return to a conventional toxicity index (CTIg) value according to the following equation:

[0163] [Math. 2] in which a is the concentration measured in mg.rrr 3 of the i ème gas in the smoke chamber according to ISO 5659-2, and G is the reference concentration measured in mg.rrr 3 of the i ème gas and given in standard EN17084.

[0164]

[0114] The second method is based on the NF X70-100 standard which also allows the toxicity of gaseous effluents to be measured but using a tubular furnace at a temperature of 600°C. This test allows us to return to a conventional toxicity index value for non-listed products (ITCPNL) according to the following equation [Math. 3] in which Y is the yield at i ème gas in the tubular furnace according to NF X70-100-1, and Ci is the reference concentration measured in mg.rrr 3 of the i ème gas and given in standard EN17084.

[0165]

[0115] For these two indices, the toxicity assessment is carried out on 8 gases (CO2, CO, HBr, HCl, HCN, HF, SO2, NOx including NO2 and NO,).

[0166]

[0116] D3. Formatting samples

[0167]

[0117] In order to evaluate these performances, the granules obtained by twin-screw extrusion must be shaped into a test piece. To do this, two methods have been used within the framework of the invention with thermopressing and 3D printing. Generally, thermopressing is carried out at a temperature above the melting temperature for semi-crystalline polymers and above the glass transition temperature for amorphous polymers. In order to achieve the required dimensions, a mold with the desired thickness is used and put under pressure (force). The temperature and force profile depends on the nature of the polymer.

[0168]

[0118] Finally, the evaluation of the printability of the material and its fire performance after printing requires the use of a melt additive manufacturing technology. To do this, a pellet printer based on Pellet Additive Manufacturing (PAM) technology was used. The implementation by PAM printing makes it possible to produce specimens with the required dimensions as mentioned above. This makes it possible to evaluate the fire performance according to the 3 fire tests of the HL2-R22 fire / smoke requirement in a similar way to the thermo-compressed specimens.

[0119] Furthermore, in order to comply with the EN45545 standard and the fire requirement relating to the part, the material must be tested as close as possible to the final thickness of the part. However, the material can also be tested over a range of thicknesses and it is then appropriate to test the maximum and minimum thickness. Intermediate values ​​are then considered to comply with the requirement.

Claims

Claims 1. Flame-retardant material composition usable for 3D printing, characterized in that it comprises or is strictly composed of: - 35% to 79% by weight of at least one bio-sourced polycarbonate copolymer relative to the total weight of the composition, said bio-sourced polycarbonate copolymer comprising at least repeating units resulting from the polymerization of the 1,4:3,6-dianhydrohexitol monomer and at least repeating units resulting from the polymerization of a monomer of a dihydroxylated alicyclic component; - 10% to 20% by weight of organic phosphorus compound relative to the total weight of the composition, - 10% to 15% by weight of a zinc molybdate and magnesium silicate complex relative to the total weight of the composition, - 0.1% to 15% by weight of a carbonate relative to the total weight of the composition, and, - optionally 0.1% to 15% talc relative to the total weight of the composition.

2. Composition according to claim 1, comprising: - 40% to 70% by weight of at least one bio-sourced polycarbonate copolymer relative to the total weight of the composition, - 10% to 15% by weight of organic phosphorus compound relative to the total weight of the composition, - 10% to 15% by weight of a zinc molybdate and magnesium silicate complex relative to the total weight of the composition, - 2% to 10% by weight of a carbonate relative to the total weight of the composition, and, - optionally 2% to 10% talc relative to the total weight of the composition.

3. Composition according to claim 1 or 2, comprising: - 65% by weight of at least one bio-sourced polycarbonate copolymer relative to the total weight of the composition, - 12.5% by weight of organic phosphorus compound relative to the total weight of the composition, - 12.5% by weight of a zinc molybdate and magnesium silicate complex relative to the total weight of the composition, - 5% by weight of a carbonate relative to the total weight of the composition, and, - optionally 5% talc relative to the total weight of the composition.

4. Composition according to claim 1 or 2, comprising: - 70% by weight of at least one bio-sourced polycarbonate copolymer relative to the total weight of the composition, - 12.5% by weight of organic phosphorus compound relative to the total weight of the composition, - 12.5% by weight of a zinc molybdate and magnesium silicate complex relative to the total weight of the composition, - 5% by weight of a carbonate relative to the total weight of the composition.

5. Composition according to any one of claims 1 to 4, in which the 1,4:3,6-dianhydrohexitol is chosen from 1,4:3,6-dianhydro-D-sorbitol, 1,4:3,6-dianhydro-D-mannitol and 1,4:3,6-dianhydro-L-iditol.

6. Composition according to any one of claims 1 to 5, wherein said organic phosphorus compound is selected from phosphonates, phosphinates, phosphites, phosphazenes and a mixture of two or more thereof.

7. Composition according to claim 6, in which said organic phosphorus compound is chosen from alkylphosphinates, preferentially from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-melamine and aluminum diethylphosphinate.

8. Composition according to any one of claims 1 to 7, in which the carbonate is calcium carbonate.

9. 3D printing powder, 3D printing granule or 3D printing filament, comprising or strictly consisting of the flame retardant material composition according to any one of claims 1 to 8.

10. Part intended for the railway industry comprising or being strictly made up of the composition according to any one of claims 1 to 8.

11. Rail transport means comprising a part according to claim 10.

12. Method for manufacturing a flame retardant material comprising or strictly consisting of the composition according to any one of claims 1 to 8, said method comprising the following steps of: - heating of the bio-sourced polycarbonate copolymer; - adding to the heated biosourced polycarbonate copolymer said at least one organic phosphorus compound, said zinc molybdate and magnesium silicate complex, said at least one carbonate and optionally talc, so as to obtain the flame retardant material composition which is the subject of the present invention, the biosourced polycarbonate copolymer being present in the composition at a level of 35% to 79% by weight relative to the total weight of the composition, the organic phosphorus compound at 10% to 20% by weight relative to the total weight of the composition, the zinc molybdate and magnesium silicate complex at 10% to 15% by weight relative to the total weight of the composition, the carbonate at 0.1% to 15% by weight relative to the total weight of the composition and the talc at 0.1% to 15% by weight relative to the total weight of the composition; - mixing of the flame retardant material composition; - cooling said composition so as to obtain the flame retardant material.

13. A method of preparing a three-dimensional shaped product by means of 3D printing, injection, thermoforming or thermocompression from the flame retardant material composition according to any one of claims 1 to 8.

14. Method for preparing a three-dimensional shaped product by means of 3D printing according to claim 13, said method comprising the steps, preferably successive, of: - providing a flame retardant material composition according to any one of claims 1 to 8; - heating defined portions of the flame retardant material composition above the glass transition temperature of said composition; - preparing the three-dimensional shaped product from the heated flame retardant material composition; - cooling the heated flame retardant material composition to obtain the solid three-dimensional shaped product.

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