POLYARYLENE SULPHIDE COMPOSITIONS

Abstract: A composition comprising an intimate mixture of a polyarylene sulphide with an aryl ester of an aryl alcohol, the ester being in solid solution in the resin. The preferred mixture comprises polyphenylene sulphide and benzyl benzoate. There is also described a method of curing polyarylene sulphide in which the solid solution of the ester in the resin is formed and this is heated so that the ester evaporates and the resin cures simultaneously.

Description: ι s cresert in n i n re s Ξ o ir lyarvlsre sulphide compositions. J t Polyarylene sulphides have properties which make then suitable for use ir. various, situations, for e.v.C!"—".."_/ " __ι_ p ncssess - roDerties which make their "oreOarati.cn and application inconvenient and frequently difficult. Available techniques involve the use of toxic chemicals or techniques involving what is essentially powder fusion. The powder fusion techniques limit the roles in which polyarylene sulphides can be used and involve slow processes of low productivity. -D . One of the properties of polyarylene sulphides which limits their use is their high viscosities in the nolten state. This renders the distribution of the material difficult ir. the extreme and makes it difficult therefore to es t ablish a bend between the 20. polyarylene sulphide, and another material. Ore known method of forming a bond between the tolyarylene sulphide and another material is to apply the poly¬ arylene sulphide powder to the other material as level ana eve ■ niy as possic-ie • ■ v. ", Ulc melt, cure and 25. cross-link the powder. Water based dispersions of ??S are also known but this is ^.us another form of applying powder since this is what remains after the water has been evaporated. using polyarylene s it- ice m c-L" •m • 7^ τ r-; __r — — ■L o difficulties. Polyphenylene sulphide takes a long time to cure and crosslink particularly when the powder layer is relatively thick. Also since the molten powder has a high viscosity and generally does not flow or wet a 5. surface very well, this results in voids and consequently a poor bond between the polyphenylene sulphide and the other material which, bond -may fail when under load. It is also difficult to achieve a precision thick¬ ness of polyarylene sulphide which is dimensionally stabl 10. and even more difficult to produce very thin, cured layer It is an object of the present invention to provide polyarylene sulphide in a workable form in order to minimise the above difficulties in its use. The present invention is based on the discovery 15. that benzyl benzoate has a plasticizing action on polyphenylene sulphide. According to the present invention a composition of matter is characterised in that it comprises polyarylene sulphide with an aryl ester of an aryl alcohol, the ester 20. being in solution in the resin. The resin phase may further include other resins besides polyarylene sulphide in either a major or minor proportion based on the polyarylene sulphide. Such other resins may include polytetrafluoroethylene, polyimides 25. and polysulphones. The resin phase may also include fillers, pigments, dyes, surface active additives, stab¬ ilizers, cross-linking agents, coating aids such as silic or titanium oxide powders, and bases to enhance bonding. The ester of "solvent" phase may include or comprise 30. mixtures of aryl esters of aryl alcohols , for example one or more of benzyl henzoate, benzyl ph.thalate, henzyl iosphthalate, and benzyl terephthalate, and other materials acting as diluents or extenders or viscosity reducers for the active solvent and having no non-solvent 5. action such as to prevent the blend having the necessary plasticiser or solvent action for >th.e resin phase as the case may be. The solvent phase may also include co-solvents, which, whilst having no significant solvent action on their own 10. enhance the solvent action of the benzyl benzoate.. The solvent phase may als.p include, other solvents for polyphenylene sulphide and when the resin phase incl¬ udes other resins , solvents for such other resins even if .these are not solvents for polyphenylene sulphide 15. though in this case they are preferably miscible with benzyl benzoate to form a single solvent phase. The compositions of the invention may include solid . particulate materials containing polyphenylene sulphide plasticized by benzyl benzoate'or solid_ workable bodies of polyphenylene sulphide piasticized by benzyl benzoate. The compositions may take the for 0«i. S lC «rS f ( C * J used.as required. 5. The polyarylene sulphide resin that can be used in the present invention may be a polymer made by the method disclosed in -USP 3354129 " but in general can be represented as a polymer including a recurring unit o the formula in which the ring A be substituted. One such form of substitution may be represented in which: chlorine, bromine or iodine atom, preferably chlorine or bromine, and Y represents a hydrogen atom, 20, 0 0 0 R 0 v ft -R, -N(R) J -C-0R, -C-0M, -C-N(R) -N-C-E -0-R* -S-R 1 , -S0,H or -S0,M groups in which: R represents a hydrogen atom, an alkyl, cycloalk aryl, aralkyl, or alkaryl group containing 1 to 12 25. carbon atoms and in which: K represents an alkali metal atom of a sodium ci potassium atom and in which: D is 0 to 4 and c is 2 to ^. j • can be represented by the formula is preferred. The polyarylene sulphides may be partially oxidize 10, or may have a branched or cress linked structure though non-cress linked polymers cr ones having a low degree of cross linking and thus relatively lev; K.lv. are preferred e.g. these having .V. ' .'s in the range 17,500 ' to 500C. More generally polyarylene sulphides having 15. melting points in the range 280 C C to 300 ' " ' C are rref rre lso i ≥teriεls having intrinsic viscosities m chloronapthalene at 260 C oi" at least 0.1, e.g. 0.1 to 0.3 especially 0.13 to 0.23 are preferred. Polyphenylene sulphide has a solubility parameter o 0 , 8.5 to 9.5. ϋncured PPS sold under the Trade Mark Ryto V has a flow index of lOOOg/min. by the American- Society Test Kethod (ASTM, D123S). Using the same test, part cured PPS sold under the Trade Marks Ryton P2 and have melt flow indices of 300 and 125g/r. * in. respectively , In these compositions including PPS in particulate form the particle size may be in the range 10-200 microns and use of pev/ier of such particle size is convenient as a starting point for the preparation of single phase systems in accordance v:ith the invention. The r.r-eferred solvent ccr.nour.ds for use in the present invention may be represented by the formula 5. where X, Y, ¥ and Z represent a hydrogen atom or a halogen atom e.g. a chlorine atom. The most preferred compound is Compound I, when X, Y, " W and Z are all hydrogen. A less preferred compound is Compound I when W or Z is chlorie and X, Y 10. and Z or V are hydrogen, namely benzyl monochloroben∑oa Benzyl benzoate has the following properties: melting point 18-20°C boiling point 320°C solubility parameter 9.3 15. Other solvent compounds which may be used in the present invention may comprise phenyl benzoate, di- phenyl phthalate, di-benzyl ether, benzoic. anhydride an di-phenyl sulphone. According to another aspect of the invention a 20. -method of curing a polyarylene sulphide is characterised by mixing polyarylene sulphide with an aryl ester of an aryl alcohol, whereby the polyarylene sul¬ phide is plasticised . : subsequently evaporating the ester and at least partly curing the polyarylene sul- 25. phide simultaneously to leave the polyarylene sulphide in an at least partly cured state. The mixture preferab forms a single continuous phase. Preferably the polyarylene sulphide is polyphenyle sulphide and preferably the ester is benzyl benzoate. 30. The plasticised mixture may be heated until one continuous liquid phase is formed. The liquid may be cooled at this stage for example in order to promote . ? - .^*f*ι* 4 ** 4 ^ 2 ^-.r . _^ * -t .— •£* -i-v, Λ «_- _-*.,_-. j -^ — • — , p ^*^ * -, ^ , — «r » -r ^ ^ ^ _ ^,- r era" 1 c _/α. VWJ., * w ww ti * W**w -__. s__.0-.A- ^ - l * C A * * * * — .*..^*~ M » . __3 U£»«__ in the ester. 5. This step is not absolutely necessary in all cases but may be advantageous for example if it is desired to store the formulation for any length of time. Preferably the nature of the ester and he resin are such that when the mixture is heated the resin ' and 10. ester form a single phase and as the ester evaporates, the resin undergoes curing. Preferably the ester does not evaporate completely until the resin is almost completely cured. Preferably a minimum of ester is employed since this may be lost in evaporation. 15_ The method according to the invention may therefore rend.er it possible to produce a cured polyarylene sulphide in the form of a thin film having a thickness hitherto thought to be unobtainable for example as low as 3 x 10 "" m or less. 20. The invention also extends to the use of the ester as an adhesive for the resin. A hot melt adhesive may be formed which comprises a sheet of plasticised resin. This may be used 'to join adjacent surfaces of for example aluminium or an aluminium alloy. 25. The invention may be carried, into practice in various ways and will be illustrated in the following specific examples. All percentages in the following examples are by weight. - EXAMPLE 1- 30. Dry Spinning of Fibres. Polyphenylene sulphide fibres were dry spun by pumping a 40% solution of uncured polyphenylene sulphid m Denzy oenzoa e .neat.ec. t.o ^__,G s-u r 'l_ t. -.rougn a spinneret consisting of a 3" diameter (7.62 cm) steel disc 5. containing 60 countersunk holes of 250 micron dia.. Fibre drawing rate, solvent evaporation, curing and cooling rate at the exit to the spinneret were optimis to produce strong, tough fibres which were then wound together to form a yarn. 10. EXAMPLE 2 Wet Spinning of Fibres. Polyphenylene- sulphide fibres were wet spun by pumping a 0% solution of uncured polyphenylene sulphi in benzylbenzoate heated to 26θ°C into a bath containi 15. dyphenyl ether. Fibre drawing, heat treating and drawing conditions were controlled to produce tough, strong fibres which were then wound together to form a yarn. EXAMPLE 3 20. Solvent Casting of a Film. A thin (25 microns) film of polyphenylene sulphid was cast by allowing a 0% solution of uncured poly¬ phenylene sulphide in benzylbenzoate at 260 C to flow onto a smooth continuous stainless steel belt treated 25. with release agent. After carefully controlled heat treatment the polyphenylene sulphide was stripped from the casting surface as strong, toug even continuous film. EXAMPLE 4 30. Film Extrusion. Cured lightly cross linked polyphenylene sulphide with 30% diphenyl sulphone plasticiser was extruded using- a screw extruder and calended to give a 125 micro thick- strong, tough, even film. 5. EXAMPLE 5 Adhesives. A solid hot melt adhesive formulation was made by rapidly cooling a gel formed from cured lightly cross linked polyphenylene sulphide blended at 26θ°C with 40% 10. diphenyl sulphone. The adhesive was cast in the form o a 500 micron sheet on a glass fibre support. Flat shea test specimens were formed by sandwiching the adhesive sheet between abraded aluminium test specimens and melting and curing the adhesive under a pressure of' 500 5, psi (3.45 x 10 N/M ) at a temperature of 300°C for 30 minutes. Room temperature tensile shear tests gave a streng of 25 MN/m , the same test repeated after 24 hours in boiling water produced a result of 19.9 MN/m , demonstr 20. ting the extreme resistance of the adhesive system to water, comparing very favourably with known structural adhesives for aluminium.

Claims: CLAIMS 1. A composition of matter is characterised in that it comprises polyarylene sulphide mixed with an aryl ester of an aryl alcohol, the ester being in solution in the resin. 2. A composition as claimed in Claim 1 character¬ ised in that the polyarylene sulphide is polyphenylene sulphide. 3. A composition as claimed in Claim 1 cr Claim 2 characterised in that the ester is benzyl benzcate. 4. A method of curing a polyarylene sulphide characterised by mixing polyarylene sulphide with an aryl ester of an aryl alcohol, whereby the polyarylene sulphide is piasticized, subsequently evaporating the ester and at least partly curing the polyarylene sulphide simultaneously to leave the polyarylene sulphide in an at least partly cured state. 5. A method as claimed in Claim 4 characterised by heating the mixture until a single continuous liquid phase is formed and subsequently cooling the mixture to promote precipitation of.the resin in the form of fine crystals. 6. A method of curing polyarylene sulphide substantially as herein specifically described in any one of Examples 1 to 5. KIL3URN & STRODE, Chartered Patent Agents, Agents for the Applicants

Inventors: GLYNDWR J
Applicants: GLACIER METAL CO LTD, GLYNDWR J
Application year: 1981
Main classification: C08L81
IPC codes: C08K5, C08L81