Compositions with improved flammability and mechanical properties

Abstract

A flame-retardant composition which contains at least one polyphenylsulfide polymer, at least one thermoplastic elastomer containing epoxy functional groups and a polyorganosiloxane polymer having at least one epoxy functional group. A method of improving the flame resistance of impact resistant polyphenylsulfide polymer compositions is provided.

Description

1 / 22 SSPU 2025 / 002 COMPOSITIONS WITH IMPROVED FLAMMABILITY AND MECHANICAL PROPERTIES

[0001] This application claims priority to European patent application N°25155745.0 filed on 04 / 02 / 2025, the whole content of this application being incorporated herein by reference for all purposes.Technical Field

[0002] The invention relates to flame resistant compositions comprising a polyphenylsulfide polymer and which are provided with excellent mechanical properties.Background Art

[0003] In the field of advanced materials, polyphenylsulfide compositions are highly valued for their exceptional thermal stability, chemical resistance, and mechanical strength. These properties make polyphenylsulfide an ideal candidate for applications in demanding industries such as aerospace, automotive, and electronics. However, a significant challenge persists in balancing the mechanical properties of polyphenylsulfide with its flame-retardant ones, particularly when enhancing its impact resistance and deformation at break.

[0004] The integration of thermoplastic elastomers into polyphenylsulfide compositions has been explored as a mean to significantly improve the material's mechanical performance, such as its deformation at break and impact properties. Despite these enhancements, the inclusion of thermoplastic elastomers adversely affects the flame-retardant properties of the material. For instance, a composition containing merely 10 wt% of a thermoplastic elastomer fails to achieve a V-0 rating under the UL 94 flammability standard, which is a critical requirement for many industrial applications. UL 94, Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances testing, is plastic flammability test developed by Underwriters Laboratory (USA). The rating V-0 under this standard identifies polymeric materials for which “burning stops within 10 seconds on a vertical part allowing for the dripping of particles that are not inflamed”.2 / 22 SSPU 2025 / 002

[0005] Traditional approaches to improving flammability characteristics often involve the use of flame retardants. However, these substances are less and less accepted in modem material design. Therefore, there is a pressing need for innovative solutions that enhance both the mechanical and flame-retardant properties of polyphenylsulfide compositions without relying on conventional flame retardants.

[0006] The present invention addresses this challenge by introducing polyorganosiloxane polymers having at least one epoxy functional group into polyphenylsulfide formulations containing thermoplastic elastomers. Remarkably, even at small concentrations, these polyorganosiloxane polymers significantly enhance the mechanical performance of the composition while simultaneously imparting flame retardancy properties. This novel approach not only meets the stringent requirements for mechanical strength and flammability resistance but also aligns with the growing demand for more sustainable material solutions.Summary of invention

[0007] It has now been found that certain compositions comprising at least one polyphenylsulfide, at least one thermoplastic elastomer containing epoxy functional groups and at least one polyorganosiloxane polymer having at least one epoxy functional group allow obtaining an unexpected balance between mechanical properties and flame retardancy.

[0008] Object of the invention is a composition [composition (C)] comprising:80.0 to 92.5 wt% of a polyphenylsulfide polymer [polymer (PPS)]; 6.0 to 13.0 wt% of a thermoplastic elastomer containing epoxy functional groups [polymer (TPE)]; and0.5 to 5.0 wt% of a polyorganosiloxane polymer having at least one epoxy functional group [polymer (POS)];all percentages by weight being referred to the total weight of the composition (C).

[0009] The inventive composition can be shaped into parts having a V-0 rating, as determined according to the UL 94 Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances, and mechanical properties, such as elongation and impact strength, which comply with the3 / 22 SSPU 2025 / 002 needs of many applications. In addition to having UL 94 V-0 rating, both in 0.8 mm and 1.6 mm test pieces, the composition exhibits deformation at break greater than 30 % (measured at 23°C according to ISO 527-2) and / or a notched Charpy impact greater than 30.0 kJ / m2(measured according to ISO 179 / 1eA).Description of invention

[0010] An object of the invention is a composition [composition (C)] comprising:- 80.0 to 92.5 wt% of a polyphenylsulfide polymer [polymer (PPS)];- 6.0 to 13.0 wt% of a thermoplastic elastomer containing epoxy functional groups [polymer (TPE)], and- 0.5 to 5.0 wt% of a polyorganosiloxane polymer having at least one epoxy functional group [polymer (POS)];all percentages by weight being referred to the total weight of the composition (C).

[0011] For the purposes of the present description:- the use of parentheses before and after symbols or numbers identifying compounds, chemical formulae or parts of formulae has the mere purpose of better distinguishing those symbols or numbers from the rest of the text and hence said parentheses can also be omitted;- the expression “a” or “an” when referred to a component of a group or a composition should be understood as meaning “at least one”;- the expression such as “Object P comprises at least the elements p1 , p2... pi” should also be understood as encompassing explicitly the embodiment wherein Object P consists essentially of the elements p1 , p2 ...pi;- the expression “consisting essentially of” or “essentially consisting of” indicates that the referred to composition contains less than 5.0 wt%, typically less than 2.0 wt% or less than 1.0 wt%, of any other ingredient; - the expression “substantially free of X” is used herein to indicate that the amount of X is less than 5.0 wt%, preferably less than 3.0 wt%, typically less than 1.0 wt%;4 / 22 SSPU 2025 / 002 - any recitation herein of numerical ranges by endpoints includes all numbers subsumed within the recited ranges as well as the endpoints of the range and equivalents.

[0012] It should be understood that the elements, properties, and / or the characteristics of a composition, product or article, a process, or a use, described in the present specification, may be combined in all possible ways with the other elements, properties and / or characteristics of the composition, product or article, process or use, explicitly or implicitly, this being done without departing from the scope of the present description.

[0013] Should the disclosure of any patents, patent applications, and publications that are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.

[0014] The polyphenylsulfide polymer [polymer (PPS)]

[0015] Composition (C) comprises at least one polyphenylsulfide polymer, hereinafter referred to as polymer (PPS).

[0016] In its broadest definition, polymer (PPS) can comprise substituted and / or unsubstituted phenylenesulfide groups.

[0017] According to the present invention, polymer (PPS) denotes any polymer comprising at least 50 mol% of recurring units (RPPS) of formula (A), the mol% being based on the total number of moles of recurring units in the polymer (PPS):where R is independently selected from the group consisting of halogen, C1-C12 alkyl groups, C7-C24 alkylaryl groups, C7-C24 aralkyl groups, C6- C24 arylene groups, C1-C12 alkoxy groups, and C6-C18 aryloxy groups, and i is independently zero or an integer from 1 to 4.

[0018] According to formula (A), the aromatic ring of the recurring unit (RPPS) may contain from 1 to 4 radical groups R. When i is zero, the corresponding aromatic ring does not contain any radical group R.5 / 22 SSPU 2025 / 002

[0019] Polymer (PPS)is preferably any polymer comprising at least 50 mol% of recurring units (RPPS) of formula (A’), that is recurring units of formula (A) where i is zero:

[0020] According to an embodiment of the present invention, polymer (PPS) is such that at least 60 mol %, at least 70 mol %, at least 80 mol %, at least 90 mol %, at least 95 mol %, at least 99 mol % of the recurring units in the polymer (PPS) are recurring units (RPPS) of formula (A) or (A’). The mol% are based on the total number of moles of recurring units in the polymer (PPS).

[0021] Polymer (PPS) may additionally comprise units of any of formulae (Rpps-m) or (RPPS-O):being understood that when polymer (PPS) further comprises units (RPPS-m) and / or (RPPS-O), the total concentration of recurring units (RPPS- ) and / or (RPPS-O) in the polymer (PPS) is at most 10 mol%, at most 5 mol%, at most 3 mol%, at most 1 mol%, based on total amount of units (RPPS), (RPPS- ) and (RPPS-O).

[0022] In some embodiments, polymer (PPS) is an acetic acid washed polymer (PPS).

[0023] Advantageously, polymer (PPS) is such that 100 mol % of the recurring units are recurring units (RPPS) of formula (A) or (A’). Even more6 / 22 SSPU 2025 / 002 advantageously, polymer (PPS) consists essentially of recurring units (RPPS) of formula (A) or (A’).

[0024] Suitable polymers (PPS) are commercially available under the tradename Ryton® PPS from Solvay Specialty Polymers USA, LLC. In the text of the application, a product Ryton® PPS starting with the prefix ‘QA’ such as QA200N means an acid-washed PPS.

[0025] The melt flow rate of polymer (PPS) may be from 50 to 400 g / 10 min, for example from 60 to 300 g / 10 min or from 70 to 200 g / 10 min. The melt flow rate of polymer (PPS) is measured at 316°C under a weight of 5 kg according to ASTM D1238, procedure B. For example, Ryton® PPS QA 220N and QA 200N have a melt flow rate of 160 g / 10 min, and 100 g / 10 min, respectively.

[0026] Composition (C) comprises a polymer (PPS) in an amount of at least 81.0 wt%, at least 81.5 wt%, even at least 82.0 wt%, based on the total weight of the composition.

[0027] Composition (C) comprises a polymer (PPS) in an amount of 92.0 wt% or less, even of 91.5 wt% or less, based on the total weight of the composition.

[0028] Preferably, the composition comprises a polymer (PPS) in an amount of 82.5 wt% to 92.5 wt%, even of 83.5 to 92.0 wt%, based on the total weight of the composition.

[0029] When more than one polymer (PPS) is present in composition (C) the percentages above refer to the combined amount of all polymers (PPS) in the composition.

[0030] The thermoplastic elastomer containing epoxy functional groups - [polymer (TPE)]

[0031] The composition comprises at least one thermoplastic elastomer containing epoxy functional groups, hereinafter referred to as polymer (TPE).

[0032] In the context of the present invention, an "elastomer" is defined as a polymeric material presenting: (1) a low glass transition temperature (Tg), that is to say a glass transition temperature below 25°C, even below 0°C, and (2) a low modulus (Young's Modulus), that is to say a modulus below 200 MPa or even below 100 MPa.7 / 22 SSPU 2025 / 002

[0033] The polymer backbone of the polymer (TPE) can be selected from elastomeric backbones comprising polyethylenes and copolymers thereof, e.g. ethylene-butene; ethylene-octene; polypropylenes and copolymers thereof; polybutenes; polyisoprenes; ethylene-propylene-rubbers (EPR); ethylene-propylene-diene monomer rubbers (EPDM); ethylene-acrylate rubbers; butadiene-acrylonitrile rubbers, ethylene-acrylic acid (EAA), ethylene-vinylacetate (EVA); acrylonitrile-butadiene-styrene rubbers (ABS), block copolymers styrene ethylene butadiene styrene (SEBS); block copolymers styrene butadiene styrene (SBS); core shell elastomers of methacrylate-butadiene-styrene (MBS) type, or mixture of one or more of the above.

[0034] The polymer (TPE) used in the composition comprises epoxy functional groups. The functionalization of the backbone can result from the copolymerization of monomers which include epoxy functional groups or from the grafting of the polymer backbone with a further component comprising epoxy functional groups.

[0035] Specific examples of polymer (TPE) are poly(ethylene-co- glycidylmethacrylate) copolymers, poly(ethylene-co-methyl (meth)acrylate- co-glycidyl acrylate) copolymers, poly(ethylene-co-n-butyl acrylate-co- glycidyl acrylate) copolymers as well as copolymers of styrene and glycidyl (meth)acrylates. Notable, non-limiting, examples of commercially available polymer (TPE)s suitable for composition of the invention, are for instance Lotader® AX8900 and Lotader® AX8840 from Arkema which are, respectively, a poly(ethylene-co-alkylacrylate-co-glycidyl acrylate) terpolymer (compirising structural units derived from 67 wt% ethylene, 25 wt% methylacrylate, and 8 wt% glycidyl methacrylate) and a poly(ethylene- co-glycidylmethacrylate) copolymer (comprising structural units derived from 92 wt% ethylene and 8 wt% glycidyl methacrylate) or Igetabond® BF- E from Sumitomo Chemical also a poly(ethylene-co-glycidylmethacrylate) copolymer (comprising structural units derived from 88 wt% ethylene and 12 wt% glycidyl methacrylate). Another example of a suitable polymer (TPE) is commercially available from Dow Inc. (Midland, Ml, USA) under the trade name Paraloid™ EXL 2314, which is a core-shell type acrylate based polymer comprised of a core primarily comprised of cross-linked poly(n-8 / 22 SSPU 2025 / 002 butyl acrylate) rubber and of a shell comprised primarily of a poly(methyl methacrylate)-poly(glycidyl methacrylate) copolymer.

[0036] Good results in terms of mechanical properties improvement are observed when polymer (TPE) is a poly(ethylene-co-glycidylmethacrylate) copolymer, preferably a poly(ethylene-co-glycidylmethacrylate) copolymer comprising 12 wt% glycidyl methacrylate structural units.

[0037] Composition (C) preferably comprises a polymer (TPE) which has a melt flow rate of less than 10 g / 10 min, for example less than 7 g / 10 min, less than 6 g / 10 min, less than 5 g / 10 min, or less than 4 g / 10 min. The melt flow rate of polymer (TPE) is measured according to ASTM D1238, at 190°C with 2.16 kg load.

[0038] Composition (C) comprises a polymer (TPE) in an amount of 6.0 wt%, preferably at least 6.5 wt%, even at least 7.0 wt%, based on the total weight of the composition.

[0039] Advantageously, composition (C) comprises a polymer (TPE) in an amount of 13.0 wt% or less, 12.8 wt% or less, even 12.5 wt% or less based on the total weight of the composition.

[0040] Preferably, composition (C) comprises polymer (TPE) in an amount of 6.5 to 12.8 wt%, more preferably of 7.0 to 12.5 wt%, based on the total weight of the composition.

[0041] When more than one polymer (TPE) is present in composition (C) the percentages above refer to the combined amount of all polymers (TPE) in the composition.

[0042] The polyorganosiloxane polymer having at least one epoxy functional group - [polymer (PCS)]

[0043] Polymer (PCS) is a polyorganosiloxane polymer. The expression “polyorganosiloxane” is hereby used to refer to a polymer comprising a sequence of recurring units, whereas said recurring units comprise an organo-substituted catenary silicon atom bound to a catenary oxygen atom.

[0044] Polymer (PCS) comprises at least one epoxy functional group. It may comprise only one of epoxy or amie functional group, or it may comprise a plurality thereof. Further, the at least one epoxy functional group may be comprised in polymer (POS) as a pendant group in a recurring unit (e.g. as9 / 22 SSPU 2025 / 002 substituent on an organo group bonded to a catenary silicon atom), or it may be comprised as chain end.

[0045] Within the context of the present invention, the expression “epoxy functional group” is hereby used according to its usual meaning, i.e. designating a functional group including an oxygen atom joined by single bonds to two adjacent carbon atoms, thus forming a three-membered epoxide ring; in particular the epoxy functional group encompasses notably groups of formula:- RCH - CH?owith R being H or CH3.

[0046] Polymer (POS) generally complies with formula (I):wherein:each of Q, equal to or different from each other, is an epoxy group or a group selected from C1-C10 alkyl groups and C6-C10 aromatic groups, with the proviso that at least one Q is an epoxy group; R1 , R2, R3 and R4, equal to or different from each other, are selected from C1-C10 alkyl groups and C6-C10 aromatic groups, n varies between 2 and 70, preferably between 2 and 60, and p is zero or 1.

[0047] Preferably, R1 and R2, equal to or different from each other, represent an alkyl group such as methyl, ethyl, or propyl, or an aromatic group such as phenyl or naphthyl. Preferably, R3 and R4 are alkylene groups such as methylene, ethylene, or propylene, or aromatic groups such as phenylene.

[0048] Preferably, polymer (POS) is a polydimethylsiloxane (PDMS) polymer, wherein R1 and R2 are methyl groups, R3 is a propylene group, p is 1 and R4 is a methylene group.

[0049] Accordingly, polymer (POS) generally complies with formula (II):10 / 22 SSPU 2025 / 002wherein:each of Q, equal to or different from each other, is an epoxy group or a group selected from C1-C10 alkyl groups and C6-C10 aromatic groups, with the proviso that at least one Q is an epoxy group; and n varies between 2 and 70, preferably between 2 and 60.

[0050] More preferably, in polymer (POS), according to both formulae sketched above, each of Q is an epoxy group, that is to say that in polymer (POS) each chain end is an epoxy group.

[0051] Polymer (POS) preferably has a weight-average molecular weight (Mw) of at most 5,000 g / mol, at most 4,800 g / mol, at most 4,500 g / mol, at most 4,000 g / mol, at most 3,000 g / mol, at most 2,000 g / mol, at most 1 ,200 g / mol, as determined by gel permeation chromatography.

[0052] Polymer (POS) has a weight-average molecular weight (Mw) of at least 200 g / mol, at least 300 g / mol, at least 400 g / mol, as determined by gel permeation chromatography.

[0053] Composition (C) comprises a polymer (POS) in an amount of 0.5 wt% or more, 0.7 wt% or more, preferably 1.0 wt% or more, based on the total weight of Composition (C).

[0054] The amount of a polymer (POS) in composition (C) is at 5.0 wt% or less, 4.0 wt% or less, even 3.0 wt% or less, based on the total weight of Composition (C).

[0055] Good results were obtained with an amount of polymer (POS) of 0.7 to 3.0 wt%, preferably from 1.0 to 2.5 wt% based on the total weight of Composition (C).

[0056] When more than one polymer (POS) is present in composition (C) the percentages above refer to the combined amount of all polymers (POS) in the composition.

[0057] Good results in terms of balance of mechanical and flame-retardant properties were obtained with a composition (C) comprising:- 80.0 to 92.0 wt% of a polymer (PPS);11 / 22 SSPU 2025 / 002 - 7.0 to 13.0 wt% of a polymer (TPE); and- 1.0 to 2.5 wt% of a polymer (POS);all percentages being referred to the total weight of the composition (C).

[0058] Excellent results in terms of balance of mechanical and flame-retardant properties were obtained with a composition (C) comprising:- 82.5 to 92.0 wt% of a polymer (PPS);- 7.5 to 12.8 wt% of a polymer (TPE); and- 1.0 to 2.5 wt% of a polymer (POS);wherein all percentages are referred to the total weight of the composition (C).

[0059] Composition (C) can optionally comprise additives. Optional additives include but are not limited to antioxidants (e.g., ultraviolet light stabilizers and heat stabilizers), processing aids, nucleating agents, lubricants, smoke-suppressing agents, anti-static agents, anti-blocking agents, colorants, pigments.

[0060] When present, additives are contained in composition (C) in an amount typically not exceeding 10.0 wt%, even not exceeding 8.0 wt% or not exceeding 5.0 wt% with respect to the total weight of the composition. Additives are generally present in an amount of at least 0.5 wt%, for example at least 0.8 wt% or at least 1.0 wt% with respect to the total weight of the composition.

[0061] One or more pigments can be desirable additives to provide a white, black or colored article. The pigment may be a black pigment suchas carbon black, a white pigment such as zinc oxide, zinc sulfide, lithopone, antimony white and titanium dioxide (of rutile or anatase type, preferably rutile type), and / or a colored pigment. A pigment is generally present in an amount of from 0 to 6.0 wt%, preferably from 0.05 to 5.0 wt%, more preferably from 0.1 to 3.0 wt%, based on the total weight of the composition.

[0062] Antioxidants can be particularly desirable additives. Antioxidants can improve the heat and light stability of the composition. For example, antioxidants that are heat stabilizers can improve the thermal stability of the composition during manufacturing (or in high heat application settings),12 / 22 SSPU 2025 / 002 for example, by making the polymer processable at higher temperatures while helping to prevent polymer degradation.

[0063] Desirable antioxidants include, but are not limited to, copper salts (e.g., CuO and CU2O), alkaline metal halides (e.g., Cui, KI, and KBr, including combinations of alkaline metal halides such as, but not limited to, Cul / KI), hindered phenols, hindered amine light stabilizers (“HALS”) (e.g., tertiary amine light stabilizers) and organic or inorganic phosphorous-containing stabilizers (e.g. sodium hypophosphite or manganese hypophosphite).

[0064] Composition (C) is essentially free, preferably free, of an alkoxysilane. The term “alkoxysilane” identifies compounds of general formula:wherein a is an integer from 0 to 2; p is an integer from 1 to 3; each Rx is, independently of each other, selected from a linear, branched or cyclic C1 to C8 alkyl group; each Ry is, independently of each other, a linear or branched C1 to C4 alkyl group; each Rz is, independently of each other, a linear, branched or cyclic C1 to C12 alkanediyl group, optionally containing one or more heteroatom selected from oxygen, sulfur and nitrogen; and wherein FG is selected from the group consisting of hydrogen, an halogen or a functional group.

[0065] Any method known to the person skilled in the art may be used for the manufacture of the composition (C) of the invention.

[0066] The preparation of the composition can be carried out by any known meltmixing process that is suitable for preparing thermoplastic molding compositions. Such a process is typically carried out by heating the thermoplastic polymer above the melting temperature of the thermoplastic polymer thereby forming a melt of the thermoplastic polymer. The process for the preparation of the composition can be carried out in a melt-mixing apparatus, for which any melt-mixing apparatus known to the one skilled in the art of preparing polymer compositions by melt mixing can be used. Suitable melt-mixing apparatus are, for example, kneaders, Banbury mixers, single-screw extruders, and twin-screw extruders. Preferably, use is made of an extruder fitted with means for dosing all the desired13 / 22 SSPU 2025 / 002 components to the extruder, either to the extruder's throat or to the melt. In the process for the preparation of the polymer composition the constituting components for forming the composition are fed to the meltmixing apparatus and melt-mixed in that apparatus. The components may be fed simultaneously as a powder mixture or granule mixture, also known as dry-blend, or may be fed separately.

[0067] Advantageously, composition (C) can be provided in the form of pellets, which may be used in injection molding or extrusion processes known in the art.

[0068] Composition (C) of the invention has a V-0 rating as determined according to the UL 94 Standard (Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances of the Underwriters Laboratory (USA)).

[0069] In addition to the V-0 rating according to UL 94, composition (C) is characterised by at least one of the following properties:- an elongation at break determined at room temperature (23°C) according to standard ISO 527-2 at a speed of 50 mm / min of not less than 30%, preferably not less than 33%; and- a notched Charpy impact resistance measured according to ISO 179- 1 / 1 eA at 23° (hammer 7.5J) of not less than 30.0 kJ / m2

[0070] The elongation at break can be up to 100%, it may be higher.

[0071] The notched Charpy impact resistance can be up to 90.0 kJ / m2, or it may be higher.

[0072] A second object of the invention is the use of a polymer (PCS) as detailed above to improve the flammability rating under standard UL 94 of a composition comprising a polymer (PPS) and a polymer (TPE). The amount of polymer (PCS) is from 0.5 to 5.0 wt% with respect to the total weight of the composition. Preferably, an amount of 0.5 to 5.0 wt% of polymer (PCS) is used to improve the flammability rating of a composition comprising polymer (PPS) and 6.0 to 13.0 wt% of a polymer (TPE). The UL 94 rating achieved by the addition of polymer (PCS) to the polymer (PPS) and polymer (TPE) blend is V-0.14 / 22 SSPU 2025 / 002

[0073] A further object of the invention is the use of composition (C) in making flame-retardant molded articles, particularly extrusion-molded articles, overmolded components and thin-walled molded articles.

[0074] The article is another object of the invention. The article, thanks to its excellent mechanical and flame-retardant properties, finds several uses in automotive applications, electric and electronic applications, and consumer goods.

[0075] The article can be molded from composition (C) by various molding methods such as injection molding, extrusion molding, compression molding, blow molding, and injection compression molding, preferably by injection molding and extrusion molding.

[0076] Examples of articles produced by extrusion molding include round bars, square bars, sheets, films, tubes, and pipes. Applications include electrical insulating materials for motors such as water heater motors, airconditioner motors, and drive motors, film capacitors, speaker diaphragms, printed board materials, printed board peripherals, semiconductor packages, trays for conveying semiconductors, protection films, film sensors for automobiles, insulating tapes for wire cables, insulating washers in lithium ion batteries, tubes for hot water, cooling water, and chemicals, fuel tubes for automobiles, pipes for hot water, pipes for chemicals in chemical plants, pipes for oil and gas applications, including reinforced thermoplastic pipes and downhole pipe liners, pipes for ultrapure water and ultrapure solvents, pipes for automobiles, pipes for chlorofluorocarbons and supercritical carbon dioxide refrigerants, and workpiece-holding rings for polishers. Other examples include molded articles for coating motor coil wires in hybrid vehicles, electric vehicles, railways, and power plants; and molded articles for coating heat-resistant electric wires and cables for household electrical appliances, wire harnesses and control wires such as flat cables used for the wiring in automobiles, and winding wires of signal transformers and car-mounted transformers for communication, transmission, high frequencies, audios, and measurements.

[0077] Applications of molded articles obtained by injection molding include electrical equipment components such as generators, electric motors,15 / 22 SSPU 2025 / 002 potential transformers, current transformers, voltage regulators, rectifiers, inverters, relays, power contacts, switches, breakers, knife switches, multipole rods, and electrical component cabinets; electronic components such as sensors, LED lamps, connectors, sockets, resistors, relay cases, small switches, coil bobbins, capacitors, variable capacitor cases, optical pickups, radiators, various terminal boards, transformers, plugs, printed circuit boards, tuners, speakers, microphones, headphones, small motors, magnetic head bases, power modules, semiconductors, liquid crystals, FDD carriages, FDD chassis, motor brush holders, parabolic antennas, and computer-related components; domestic and office electric appliance components such as VTR components, TV components, irons, hair dryers, rice cooker components, microwave oven components, acoustic components, audio equipment components for audios, laserdiscs (registered trademark), and compact discs, illumination components, refrigerator components, air conditioner components, typewriter components, and word processor components; machine-related components such as office computer-related components, telephone set-related components, facsimile-related components, copier-related components, cleaning jigs, motor components, lighters, and typewriters: components of optical and precision instruments such as microscopes, binoculars, cameras, and watches; automobile and vehicle-related components such as alternator terminals, alternator connectors, 1C regulators, potentiometer bases for light dimmers, various valves including exhaust gas valves, various pipes for fuels, exhaust systems, and air intake systems, ducts, air intake nozzle snorkels, intake manifolds, fuel pumps, engine coolant joints, carburetor main bodies, carburetor spacers, exhaust gas sensors, coolant sensors, oil temperature sensors, brake pad wear sensors, throttle position sensors, crankshaft position sensors, air flow meters, brake pad wear sensors, thermostat bases for airconditioners, warming hot air flow control valves, brush holders for radiator motors, water pump impellers, turbine vanes, windshield wiper motor-related components, distributors, starter switches, starter relays, transmission wire harnesses, window washer nozzles, air- conditioner panel switch boards, coils for fuel solenoid valves, fuse connectors, horn16 / 22 SSPU 2025 / 002 terminals, electric component insulators, step motor rotors, lamp sockets, lamp reflectors, lamp housings, brake pistons, solenoid bobbins, engine oil filters, and ignition cases; and gaskets for primary batteries and secondary batteries in cellular phones, notebook computers, video cameras, hybrid vehicles, and electric vehicles.

[0078] The embodiments above are intended to be illustrative and not limiting.Additional embodiments are within the inventive concepts. In addition, although the present invention is described with reference to particular embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the invention.

[0079] Should the disclosure of any patents, patent applications, and publications which are incorporated herein by reference conflict with the description of the present application to the extent that it may render a term unclear, the present description shall take precedence.

[0080] EXAMPLES

[0081] Raw Materials

[0082] PPS: Ryton® QA200N obtained from Solvay Specialty Polymers USA, L.L.C; an acid-washed PPS, having a melt flow rate of 100 g / 10 min with 5 kg load at a temperature of 316°C (ASTM D1238).TPE: Igetabond® BF-E from Sumitomo Chemical, having a melt flow rate of 3 g / 10 min (JIS K7210-1, 190°C, 21.2N) and a Tg of -26°CPCS: KF105 is a dual-end type / epoxy modified reactive silicone fluid of formula:R = H or CH3, whereas n is such that the viscosity at 25°C is 15 and the equivalent weight is 490 g / mol, commercially available from Shin-Etsu. ALK : Alkoxysilane Silquest® A-187 commercially available from Momentive

[0083] General procedure for the preparation of compositions17 / 22 SSPU 2025 / 002

[0084] A dry blend of polymer (PPS), polymer (TPE) and polymer (POS) or (ALK) was first realized and for each formulation, the targeted mass ratios of the components were mixed in a vibratory shaker for 2-3 minutes to assure homogeneity. The dry blend was then placed in gravimetric feeder and fed into a twin-screw extruder (Coperion ZSK 26 or ClextralD32), melted, and mixed with screws designed to achieve a homogeneous melt composition. Temperature during extrusion was controlled to remain under 320°C.

[0085] The melt stream was cooled and fed into a pelletizer. The pellets were collected and kept in sealed plastic buckets until used for injection molding.

[0086] Testing methods

[0087] ISO 527 type 1 A bars and thin-small parts for UL 94 tests (0.8 and 1.6 mm) were fabricated by injection molding on a Billion Injection (at 320- 330°C).

[0088] Tensile properties were determined at room temperature (23°C) according to standard ISO 527-2 at a speed of 1 mm / min for tensile modulus and a speed of 50 mm / min for strength and elongation at break.

[0089] Notched Charpy impact properties were measured according to ISO 179- 1 / 1 eA at 23° (hammer 7.5J).

[0090] Flammability was evaluated according to standard UL 94 of Underwriters Laboratory (USA) on 0.8 or 1.6 mm thick samples.

[0091] Compositions of Examples 1 to 3 and Comparative examples 1 and 2 together with their mechanical properties and flammability ratings are detailed in Table 1 where all percentages are by weight, calculated with respect to the total weight of the composition.Table 118 / 22 SSPU 2025 / 002

[0092] The results in Table 1 show that the presence of polymer (POS) in a composition of polymer (PPS) and polymer (TPE) in an amount of 6.0 to 13.0 wt% allows achieving a UL 94 flammability rating of V-0 even in thin test pieces. The inventive compositions benefit from the improved mechanical properties provided by the presence of polymer (TPE) and are at the same time provided with excellent flame retardant properties.

[0093] Examples 4 and 5 show the effect of the amount of polymer (POS) on the flame-retardant properties of the composition. The use of an alkoxysilane in place of polymer (POS) in Comparative Example 3 provides a composition having worse impact resistance and elongation at break as well failing the UL 94 flammability test. The compositions and the results are shown in Table 2.Table 219 / 22 SSPU 2025 / 002

[0094] With respect to compositions comprising PPS, TPE and an alkoysilane, the inventive composition, comprising polymer (POS), unexpectedly provides a material which meets the V-0 rating according to UL 94 flammability standard. The inventive compositions are characterised by an advantageous balance of mechanical and flame-retardant properties.

Claims

20 / 22 SSPU 2025 / 002 Claims1. A composition [composition (C)] comprising:- 80.0 to 92.5 wt% of a polyphenylsulfide polymer [polymer (PPS)];- 6.0 to 13.0 wt% of a thermoplastic elastomer containing epoxy functional groups [polymer (TPE)], and- 0.5 to 5.0 wt% of a polyorganosiloxane polymer having at least one epoxy functional group [polymer (POS)];all percentages by weight being referred to the total weight of the composition.

2. Composition of claim 1 wherein the thermoplastic elastomer containing epoxy functional groups [polymer (TPE)] is selected from the group consisting of poly(ethylene-co-glycidylmethacrylate) copolymers, poly(ethylene-co-methyl (meth)acrylate-co-glycidyl acrylate) copolymers, poly(ethylene-co-n-butyl acrylate-co-glycidyl acrylate) copolymers and copolymers of styrene and glycidyl (meth)acrylates, preferably poly(ethylene-co-glycidylmethacrylate) copolymers.

3. Composition of claim 1 or 2 wherein the polyorganosiloxane polymer having at least one epoxy functional group [polymer (POS)] is represented by formula (I)wherein:each of Q, equal to or different from each other, is an epoxy group, or a group selected from C1-C10 alkyl groups and C6-C10 aromatic groups, with the proviso that at least one Q is an epoxy group; R1 , R2, R3 and R4, equal to or different from each other, are selected from C1-C10 alkyl groups and C6-C10 aromatic groups; n varies between 2 and 70, preferably between 2 and 60; and p is zero or 1.

4. Composition of any one of claims 1 to 3 wherein the polyorganosiloxane polymer having at least one epoxy functional group [polymer (POS)] complies with formula (II):21 / 22 SSPU 2025 / 002wherein Q, and n are as defined in claim 3.

5. Composition of any one of the preceding claims wherein the polyphenylenesulfide polymer [polymer (PPS)] comprises at least 50 mol%, at least 80 mol%, even at least 95 mol% of recurring units (RPPS) of formula (A’),6. Composition of any one of the preceding claims comprising:- 80.0 to 92.0 wt%, preferably 82.5 to 92.0 wt% of a polymer (PPS);- 7.5 to 13.0 wt%, preferably 7.5 to 12.8 wt% of a polymer (TPE); and- 1.0 to 2.5 wt% of a polymer (PCS).

7. Composition of any one of the preceding claims further comprising an additive in an amount not exceeding 10.0 wt% with respect to the total weight of the composition.

8. The composition of any one of the preceding claims which is free of an alkoxysilane.

9. The composition of any one of claims 1 to 8 which has a V-0 rating as determined according to UL 94 Standard (Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances of the Underwriters Laboratory (USA)).

10. The composition of claim 9 which is further characterised by at least one of the following properties:- an elongation at break determined at room temperature (23°C) according to standard ISO 527-2 at a speed of 50 mm / min of not less than 30%, preferably not less than 33%; and- a notched Charpy impact resistance measured according to ISO 179-1 / 1eA at 23o (hammer 7.5J) of not less than 30.0 kJ / m222 / 22 SSPU 2025 / 002 11. An article comprising the composition of any one of the preceding claims.

12. The article of claim 11 which has a V-0 rating as determined according to UL 94 Standard (Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances of the Underwriters Laboratory (USA)).

13. Use of a polyorganosiloxane polymer having at least one epoxy functional group [polymer (POS)] to improve the flammability rating according to UL 94 Standard (Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances of the Underwriters Laboratory (USA)) of a composition comprising polyphenylsulfide polymer [polymer (PPS)] and 6.0 to 13.0 wt% of at least one thermoplastic elastomer containing epoxy functional groups [polymer (TPE)].

14. Use according to claim 13 wherein the rating is V-0.

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