AUSTRALIA PATENTS ACT 1990 REGULATION 3.2 Name of Applicant: SAINT-GOBAIN PERFORMANCE PLASTICS CORPORATION Actual Inventor/s: Sridhar K. Siddhamalli; Zhizhong Liu; Mark W. Simon; Charles S, Golub; Heidi Sardinha; Wayne E Garver; Mark F. Colton; Robert L. Wells; Gerald [ Stadt; Michael I Tzivanis; William Risen; and Nathan Klettlinger. Address for Service: E. F. WEL LINGTON & CO, Patent and Trade Mark Attorneys, 312 St Kilda Road, Melboune, Southbank, Victoria 3006. Invention Tide: "A FLEXIBLE TUBING MATERIAL AND METHOD OF FORMING"1 HE MATERIAL" The following statement isa full description of this invention including the best method of performing it known to us, This application is a divisional' application derived from Australian Patent Application No. 2010343054 (Interational Application No. PCT/US2010/062430 : WO 20111090759), claiming priority of US Application No. 61/290731, the entire text of which are hereby incorporated herein by reference. FIELD OF THE DISCLOSURE 15 This disclosure, in general, relates to a flexible tubing material and methods of making the aforementioned material. BACKGROUND ART Currently, flexible medical tubing is used to transport any variety of liquids during medical procedures A flexible polyvinyl chloride (PVC) is a typical material Used for medical 20 tubing due to their inherent flexibility and translucency, Unfortunately, polyvinyl chloride tubing has significant amounts of low-molecular weight chemicals that can beleached into de human body during medical treatments. Further, disposal of PVCbased wasted by incineration causes environmental issues due to the release of toxic gases. Alternative materials to flexible PVC have been adopted to make flexible medical tubing. 25 Polymem that may be desired typically include those that ar flexible, transparent, and dppropn;rate for crinplcaos.Unfortuately, these polymers may not have all the physical or mechanical properties desid for flexible medical tubing applications Further many of these polymers do not perform well under steam sterilization due to severe softening at temperatures higher than about 100*C. As a result, manufacturers are often left to choose the physical and 30 mechanical properties they desire without an option as to whether it can be steam sterilized. As such, an improved polymeric material that car be steam sterilized is desired A A- DISCLOSURE OF iNVENTION In a particular embodiment, a flexible tubing material includes a radiation crosslinked blend of: a) a first elastomeric polymer including a styrenic thermoplastic elastoner, an ethylene vinyl acetate elasomer, a polyolefin elastomer, or combination thereof; and b) a second 5 elastomeric polymer including a polyolefin elastomer, a diene elastomer, or combination thereof, with the proviso that the first elastomeric polymer and the second elastomeric polymer are different. In another exemplary embodiment, a method of making a material includes providing a first elastomeric polymer including a styrenic thermoplastic elastomer, an ethylene vinyl acetate 10 elastomer, a polyolefm elastomer, or combinations thereof providing a second elastomeric polymer including a polyolefin elastomnier a diene elastomer. combination thereof with the proviso h th the first elasomeric polymer aId the second elastomeric polymer are different; blending the first elastomeric polymer and the second elastomeric polymer; extrtding or injection molding the blend; and crosslinking the blend with radiation. 15 BRIEF DESCRI7PON OF THE DRAWINGS The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings. FIG, I includes physical properties of exemplary blends of styrenic thermoplastic elastomer and a diene elastomer before crosIinking 20 FIG, 2 includes physical properties of exmplary blends of styrenic thermoplastic elastomer and a diene elastomer after cross-linking FIG. 3 includes a graphical illustration of Dynamic Mechanical Analysis (DMA) results for exemplary blends of styretic thermoplastic elastomer and a diene elastomer with and without e-bean crsslinking treatment. 25 FIG, 4 includes physical properties of exemplary blends of styrenic thermoplastic elastomer and a diene elastomner tubing before e-beam crosslinking treatment FIG. 5 includes physical properties of exemplary blends of styrenic thermoplastic elastomer and a diene elastomer tubing after e-beani cross-linking treatment. 4i FIG. 6 includes a graphical illustration of Dynamic Mechanical Analysis (DMA) results for exemplary blends of styrenic thermoplas elastomer anda diene elastomer with and without beam cross-linking treatment, FIG. 7 includes a graphical illustration of Dynamic Mechanical Analysis (DMA) results 5 for an exemplary blend of a terpolymer of ethylene, propylene and a diene monomer (EPDM) and ethylene methyl acrylate (EMA) with and without e-beam cross-linking treatment FIG 8 includes a graphical illustration of tear testing results for exemplary blends of polyolefin elastomer and diene elastomer with and without e-beam cross-linking treatment. FIG 9 includes a graphical illustration of Dynamic Mechanical Analysis (DMA) results 10 for an exemplary blend of a polyolefin elasromeand a diene elastomer with and without e-beam cross-linking treatments FIG. 10 includes a graphicaliustration of gel content testing msultsfor exemplary blends of polyolefm elastomer and diene eLastomrer with e-beam cross-linking treatment FI. 1. I. includes physical properties of exemplary blends of thermoplastic elastomers and I5 ionomer elastomers before cross-linking. The use of the same reference symbols in different drawing indicates similar or identical items. DESCRIPTION OF THE PREFERRED EMBODIMENT(S) In a particular embodiment, a flexible tubing material includes a blend of a first 20 elastomeric polymer with a second elastomeric polymer, Typically, the first elastomeric polymer is a styrenic thermoplastic elastomer, an ethylene vinyl acetate elastomer. a polyolefin elastomer, or combination thereof. Typically, the second elastomeric polymer is a polyolefin elastomer, a diene elastomer, or combination thereof. The flexible tubing material includes the first elastomeric polyner and the second elastomeric polymer with the proviso that the first 25 elastomeric polymer and the second elastomeric polymer are different. In a particular embodiment, the first elastomneric polymer and the second elastomeric polymer are not both polyolefin elastomers, The blend of the first elastomeric polymer with the second elastomer advantageously provides a material that can be radiation crosslinked. In an example, radiation crosslinLing includes gamma radiation and e-beam radiatioa Further, the radiation crosslinked material can be sterilized. Typically, the styrenic thermoplastic elastomer is a styrene based block copolymers such as styrene-butadiene, styrenesoprene. blends thereof mixtures thereof, and the like. In an 5 embodiment, any styrenic thermoplastic elastomer is enviioned. Exemplary styrenic thermoplastic elastomers include tiblock styrenic block copolymers (SBC such as styrene butadiene-styrene (S, styreneisoprene-styrene (IS.), stvreneethyenebutylene-styrene (SEES). styrene-ethylene propylene-styrene (SEPS) styrene-ethyleneethylenebutadiene styrene (SEEBS), styrene-ethyflene-ethylenepropyleng-styrene (SEEPS) styrene-isoprene 10 butadiene-styrene (SIBS ) or combinations thereof. Commercial examples include some grades of Kraton and hybr resins. In an embodiment, the styrenic thermoplastic elastomer contains east one free olefinic double bond, i e. an unsaturated double bond. For instance, the presence of the free olefinic double bond in the polymer provides molecular sites that will crosslink under radiation. Exemplary styrenic polymers with unsaturated double bonds include 15 styrene-isoprene-butadiene-styrene(31BS), styrenelsoprene-styrene (818), styrene-butadiene~ styrene (3B5),and the like, In an embodiment, the styrenic thermoplastic elastomer is saturated, ie. does not contain any free olefinic double bonds. Typically, the styrenic thermnoplatic elastomer has a molecular number of at least about 15,000 Mn, such as at least about25000 Mn In an embodiment, the styrenic thermoplastic 20 elastomer is present at an amount of at least 10% by weight, such as at least about 20% by weight, or even at least about 30% by weight of the total weight of the blend Typically the level of the styrenic thermoplastic elastomer present in the bend may be opdmized chased on the final properties desired Typically, the ethylene vinyl acetate elastomer is an amorphous polar polymer, 25 "Amorphous" as used herein refers to a polymer that is substantially non crystalline ie with no crystalline melting point. The amount of vinyl acetate found in the ethylene vinyl acetate polymer determines the crystalliniy of the polymer. In particular, the higher the percentage of vinyl acetate in the EVA copolymer, the more the cystalline regularity of the ethylene chain is disturbed or destroyed. Crystallization is progressively hindered and is substantially absent with 30 an EVA copolymer containing about 50% vinyl acetate, rendering an amorphous polymer In an embodiment, the ethylene vinyl acetate of the present disclosure has a vinyl acetate content of greater than about 50% by weight of the total weight of the ethylene vinyl acetate For instance -4the ethylene vinyl acetate has a vinyl acetate contem of greater than about 60% by weight to about 80% by weight of the total weight of the ethylene vinyl acetate such as about 60% by weight to about 709 by weight of the total weight of de ethylene vinyl acetate. Further, the glass transition temperature. Tg, is typically low for the amorphous polymer, ide.ls than about 5 0"C In an embodiment, the glass transition temperature for amorphous ethylene tnyl acetate is less than about 0*C such as less than about - [C; or even less than about -25*C In an embodiment, the ethylene vinyl acetate has a number average molecular weight (Mn) of about 70,000 to about 90,000 such as about 80,000 to about 85,000. The ethylene vinyl acetate may have a weight average molecular weight (Mw of about 250,000 to about 40,000 such as about 10 280,000 to about 350,000. In an embodiment, the ethylene vinyl acetate has a poly dispersity index (Mw/Mn) of about 3.0 to about 5.0, such as about 35 to about 4,0. In an embodiment, the ethylene vinyl acetate has a desirable melt flow index (MI), such as about I to about 7, such as about 1.5 to about 6,at a testing parameter of 190 0 C121lN. Generally, the melt viscosity at 200*C with a 100 I/s shear rate may be up to about 600 Pas, such as about 400 Pa.s to about 500 15 Pa~s. With a 1000 I shear ratethe mdlt viscosity may be up to about 300 Pas, such as about 100 Pas to about 200 Pa s. In an embodiment the solution viscosity is up to about 2000 nPaa.s such as about 200 tnPa.s to 1500 mPasat a 15% concentration in toluene, or up to about 50,000 mPai.s such as about 7000 mPas to 30,000 mPa s at a 30% concentration in toluene. A commercially available EVA is Elvax available from DuPont 20 in an exemplary embodiment, the histomeric ethylene vinyl acetate polymer has a desirable shore A hardness, such as about 30 to about 40, In contrast, a crystanlline polar polymer, such as crystalline EVA typically has a shore A hardness of more than 40. Typically, amorphous ethylene vinyi acetate is synthesized by solution polymerizaion at a pressure of about 200 bar to about lOO0 bar and a temperature ofabout 50*C to about i20"CX In 25 an embodiment, the amorphous ethylene vinyl acetate may be synthesized by emulsion polymerization conducted at about I bar to about 200 bar pressure and temperature of 30-70*C. In contrastcrystalline ethylene vinyl acetate is prepared by mass polymerization at a pressure of about 1000 bar to about 3000 bar at a temperature of about 1 5*C to about 350*C, In an example, the blend includes the ethylene vinyl acetate present at a range of about 1% 30 by weight to about 99% by weight of the total weight of the polymeric blend In an embodimnent, the ethylene vinyl acetate is present at greater than at least about.5% by weight of the total weight of the polymeric blend, such as greater than about least about .15% by eight of the total weight of the polymeric blend, In a particular embodiment the ethylene vinyl acetate is present at greater than about least about 10% by weight of the total weight of the polymeric blend, such as a range of about 10% by weight about 90% bywight of the total weight of the polymeric blend, or even a range of about 25% byweiht to about 80% by weightof the total weightof the 5 polymeric blend. Typically, the level of the ethylene vinyl acetate present in the blend may be optimized based on the final properties desired, In a particular embodiment, the blend includes a polyoleflin elastomer Any polyolefin elastomer is envisioned A typical polyolefin may include a homopolymer, a copolymer, a terpolyner, an alloy, or any combination thereof formed from a monomer, such as ethylene, 10 propylene, butene. pentene, methyl pentene, hexeneotene, or any combination thereof In an embodiment, the polyolefin elastomer may be copolymers of ethylene with propylene or alpha olefins or copolymers of polypropylene with ethylene or alpha-olefins made by metallocene or non-metallocene polymerization processes, Commercial polvolefin examples include Affinity Engage Flexomer Veifi, Infuse Enct Vistamax:hoftef and 1 Tafmer NotioM produced by Dow, ExxonMobil, Londel-Basell and Mitsui. In an embodiment, the polyolefm ekstomer may include copolymers of ethylene with polar vinyl monomers such as acetate (EVA),acrylic acid EAAx methyl acrylate (EMA) methyl methacrylate (EMMA). ethyl acrylate (EEA)ad bury acrylate ([BA) Exemplary suppliers of these ethylene copolymer resins include DuPont Dow Chemical, Mitusi and Arkema etc. In 20 another embodiment, the polyolefin elastomer can be a terpolymer of ethylene. maleic anhydride and acrylates such as Lotade& made by Arkema'and Evalloy' produced by DuPont. In yet another embodiment, the polyolefin elastomer can be an ionomer of ethylene and acrylic acid or methacrylic acid such as Sulyn M made by DuPont. In an embodimenthe polyoltfin is a reactor grade thermoplastic polyolefin elasomer, such as P6.E2A-005B available from Flint Hills 25 Resources In an embodiment, the polyolefmn elastomers should have flexural modulus lower than 200 MPa Typically, the polyolefin elastomer is present at an amount of at least 10% by weight, such as at least about 20% by weight, or even at least about 30% by weight of the total weight of the blend. Typically, the level of the polyolefin elastomer greent in the blend may be optimized based on the final properties desired 30 In an embodimentthe blend may include a diene elastomer. Any appropriate diene elastomer is envisioned. For instance. the diene elastonmem may be polybutadiene arnd polyisoprene or their copolvmersit can also be a terpolymer of ethylene, propylene and a diene monomer (EPDM) In an embodiment, the diene elastomer may be synthesized by any means 6envisioned. For instance, the diene elastomer is synthesized by metailocene or non-metallocene polymerization processes, In an exemplary embodiment, the EPDM is a reaction product of dines such as DCPD) (dicyclopentadiene), lB (ethylidene norbomene) and VNB (vinyl norbomene). Exemprhuy EPDM resins are available from ExxonMobil Chemical as Vistalons 5 and Dow Chemical as NordelV and other suppliers, In an embodiment, the diene elastomer is present at an amount of at least 10% by weight, such as at least about 20% by weight, or even at least about 30% by weight of the total weight of the blend. Typically, the level of the diene elastomer present in the blend may be optimized based on the final properties desired, To crosslink the Mends by irradiation of e-beam or gamma rays, reactive sites are needed 10 in the blends. For instance, in the embodiment when the styrenic thermoplastic elastomer contains at least one free olefinic double bond, the free olefinic double bond in the polymer provides molecular sites that will Crosslink under radiation, in an embodiment, if saturated resins are used to make the blends, small amount of radiation sensitizers or crosslinking promoters may be added to assure sufficient crossiinking and prevent degradation of the 15 materials caused by chain scission during exposure to radiation. Any reasonable radiation sensitizer may be envisioned. Exemplary radiation sensitizers are typically multifunctional monomers such as: diethylene glycol dimetharylate (DEODMA), trimethyiolpropane trimetharcylate (TMPTMIA , dipenta erithritol acrylate (DPEA> tetramethylol methane tetraacrylate (TM.MTA), triallyl cyanurate fTAC), toluene diisocyanante (TD), hexamethylene 20 diisocyanate (IMDI), m-phenylene dimaleirmide, the like, and any combination thereof. When used, the radiation sensitizer may be present at about 0.5% to about 3.0% by weight of the total weight of the blend. In an embodiment, a crosslinking promoter may be used to provide reactive sites to crosslink the blends by irradiation. Any reasonable crosslinking promoter may be envisioned 25 Exemplary crosslinking promoters include polymers with unsaturated double bonds in the molecular chains such as polyisoprene. polybutadiene, EPDM, SS B, the like, and any combination thereof, In a particular embodiment, the unsaturated double bonds of the crosslinking promoters will crosslink by e-beam or gamma rays. Typically, the ctosslinking promoter may be present at greater than about 5.0% by weight of the total weight of the blend. 30 In an embodiment, an oil may be used in the blend, Anysuitable oil may be envisioned. In a particular embodiment, the oil is mineral oil that is either paraffnic or naphthenic or a mixture of paraffinic or napthenic with zero aromatic coent. For instance, a mineral oil may be used at an amount of about 0% by weight to about 70% by weight of the total weight of the blend. In an embodiment, the blends are substantially oil.free, "Substantialy oil-free" as used herein refers to a blend that includes mineral oil present at less than about 0.1% by weight of the total weight of the blend, For instance, the styrenic thermoplastic elastomers may be melt 5 processible without the addition of an extending oil or plasticizer. In an embodiment, the ethylene vinyl acetate elastomers may be melt processible without the addition of an extending oil or plasticizer. In an exemplary embodiment, the blend further includes any additive envisioned such as a lubricant, a filler, a plasticizer. an antiox idant, or any combination thereof. Exemplary lubricants 10 include silicone oil, waxes, slip aids, antiblock agents, and the like. Exemplary lubricants further include silicone grafted polyolefin, polyethylene or polypropylene waxes, Oleic acid aide, erucamide, stearate, fatty acid esters, and the like, Typically, the lubricant may be present at less than about 2.0% by weight of the total weight of the blend. In an embodiment, the lubricant may be present at less than about 0.5% by weight of the total weight of the blend. Exemplary 15 antioxidants include phenolic, hindered amine antioxidants. Exemplary fillers include calcium carbonate, talce radio-opaque illers such as barium sulfate, bsmuth oxychloride, any combinations thereof, and the like. Exemplary plasticizers include any known plasticizers such as mineral oils and the like. Typically, an additive may be present at an amount of not greater than about 50% by weight of the total weight of the blend, such as not greater than about 40% by 20 weight of the total weight of the blend, or even not greater than about 30% by weight of the total weight of the blend. Alternatively, the blend may be free of lubricams. fillers, plasticizers, and antioxidants The components of the blend of the first elastomeric polymer with the second elastomeric polymer may be melt processed by any known method to form the blend, In an embodiment, the 25 first elastomeric polymer with the second clastomeric polymer may be melt processed by dry blending or compounding. The dry blend may be in powder, granular, or pellet form. The blend can be made by a continuous twin-screw compounding process or batch related Banbury process. Pellets of these blends may then be fed into a single screw extruder to make articles such as flexible tubing products. Blends can alo be mixed in a single-screw exmider equipped with 30 mixing elements and then extruded directly into articles such as tubing products. In a particular embodiment, the blend can be melt processed by any method envisioned known in the art such as laminating, casting, molding, and the like. In an embodiment, the blend can be injection molded, -8- In an embodimentany artide can be made out of the blends depending on specific application need. The resulting artiIes are then irradiated using e-beam or gamma-rays in a batch process or a roll-to-roll process In a particular embodiment e-beam radiation includes an electron beam generated by a Van de Graaff generator, an eiecton-accelerator B-beam with 5 energy of between about 0.5 Mev to about 10.0 Mev from an electron beam accelerator can be used to crosslink the Wend of the resulting article. Doses between about 10 Ky to about 200 KGy (about l Mrad to about 20 Mrd) atrypical. In an exemplary embodiment, for crosslinking of the blend by gamma rays, about i Miad to about 10 Mrad of radiation from a "Co source can be used. 10 The pol ymeric blends advantageously can withstand sterilization processes. In an embodiment, the polymeric blend is sterilized by any method envisioned. For instance, the polymeric blend is sterilized after radiation crosslinking, Exemplary sterilization methods include steam, gamma, ethylene oxide, E-beam techniques, combinations thereof, and the like in a particular embodiment, the polymeric blend is sterilized by steam sterilization, In an 15 exemplary embodiment, the polymeric blend is beatresistant to steam sterilization at temperatures up to about 121*C for a time of up to about 30 minutes, In an embodiment, the polymeric blend is heat resistant to perform seam sterilization at temperature of up to about 1354C for a time of up to about 20 minutes, In an embodiment, the polymeric blend rmy be formed into a single layer article, a multi 20 layer article, or can be laminated, coated, or formed on a substrate. Multi-layer articles may include layers such as reinforcing layers, adhesive layers, barrier layers, chemically resistant layers, metal layers, any combination thereof, and the like. The blend can be formed into any useful shape such as film, sheet, tubing, and the like. The polymeric blend may adhere or bond to other substrates including polyolefns (polypropylene (PP), polyethylene (PE), and the like) 25 and styrenics (polystyrene (PS), acrylonitrile batadiene styrene (ABSt high impact polystyrene (IHPS), and the like. In a particular embodiment, the polymeric blend may be used to produce tubing and hoses, For instance, the polymeric blend can be used as tubing or hosing to produce low toxicity pump tubing, reinforced hosing, chemically resistant hosing, braided hosing. and low permeability 30 hosing and tubing. For instance, tubing may be provided that has any useful diameter size for the particular application chosen Jn an embodiment the tubing may have an outside diameter (OD) of up to about 2.0 inches. utch as about 25 inch,0.50 inch and 1.0 inch, Tubing of the 9 polymeric blend advantageously exhibits desired properties such as chemical stability and increased lifetime, For example, the tube may have a pump life greater than about 10 hours, such as greater than about 20 hours, or even greater as measured at 600RPM using a standard pump head, 5 The present embodiments can produce low toxicity articles having desirable mechanical properties. In a particular embodiment, the radiation crosslinked ardcle forced is substantially fre of plasticizers or other low-molecular weight extenders that can he leached into the fluids it transfers. "Substantially free" as used herein refers to a radiation crosslinked article having a total organics content (TOC) (measured in accordance to ISO 15705 and EPA 410.4) of less than 10 about 100 ppm. In embodiment the rulting radiation crosslinked articles may have further desirable physical and mechanical properties For instance, the radiation erosslinked articles are flexible, kink-resistant and appear transparent or at least translucent In particular, the usulting radiation crosslinked articles have desirable flexibility substantial clarity or translucency, desirable glass 15 transition temperatures, desirable low temperature peformance, and chemical resistance to oils and alcohols. Forinstance, the radiation erosslinked articles of the first elastoeric polymer with the second elastomeric polymer may advantageously produce low durometer articles, For example, a radiation crosslinked article having a Shore A dumater of between about 40 and about 90 having desirable mechanical properties may be formed Such properties ar indicative 20 of a flexible material. In addition to desirable hardness the radiation crosslinked articles have advantageons physical properties. such as desirable ultimate elongation and low compression set at elevated temperature. Ultimate elongation is determined using an nstron instrument in accordance with ASTM D-412 testing methods. For example, the radiation crosslinked articles may exhibit an 25 ultimate elongation of at least about 400% such as at least about 500%, such as at least about 600%, or evn at least about 700%. In an embodiment, the compression set in accordance with ASTM D-395 measured at about 121C of the radiation crosslinked artices is less than about 50% Applications for the polymeric blend are numerous, In particular, t1e non-toxic nature of 30 the polymeric blend makes the material useful for any application where toxicity is undesired. For instance, the polymeric blend has potential for FDA, US?, and other revelatory approvals. In an exerplary embodiment, the polymeric blend may be used in applications such as -10industrial, medical, health care, biopharmaceutical, drinking water, food & beverage, laboratory and the like. In an embodiment, the polymeric blend may also be safely disposed as it generates substantially no toxic gases when incinerated and aches no plasticizers into the environment if land filled, 5 EXAMPLES EXAMPLE 1, Blend of styrenic thermoplastic elastomer and a polyolfin Kraton 02109 is tested for mechanical and physical properties, In general terms, Kraton D2109 is a met compounded material of styrenic TPE resin, polyolefin, and mineral oil obtained from Sonneborn, Petrolia, PA. Kraton D2109 is injection molded at a flat profile of about 4004F 10 into plaques for Shore A hardness, tensile and high temperature compression set testig It is also directly extruded into 0,375" outside diameter (OD) X 0.25" inner diameter (ID) tubng. Processability is good as there are no problems with tube dimensions and temperature window, It is silky to touch (as opposed to being "grabby" as isthe case with C-Flex) and has a "silicone feel". The tube noticeably displayed signs of msilience and elasticity. The plaques and tubing 15 cols are irradiated with e-beam at 2 different dosage rates of about 6,8 MRad and about 116 MRad corresponding to 4 and 8 passes each of about 1.7 MRad, The irradiated plaques are then tested fr hardness, tensile and compression set as measured by ASTM D-395. The rsults are tabulated in Tables I and 2, Santoprene obtained from Advanced Elastomer Systems is used as comparison tubing with three grades tested fo compression set 20 Table I Properties Unexposed E4beam Exposed Kraton D)2109 j 4 Pas'ses: S Passes Shore A Hardness 49 50 52 Brak Strength, psi 475 870 4 Utimate Elongation, % 970 690 735 l2C, C Comlpression Set 12' 17.T8 11.5 Table 2 Santoprene Grade 120*C Comprssion Set 8281-64 21.2 8281-65 27.9 8281-75 30.2 5 The ebeam crossiinked tube can be heat sealed, although at a higher temperature setting than normal with standard C-Fex However heat setting temperature has to be increased from 160*C for standard C-Flex tube to about 180WC to heat seal the radiation crosslinked Kraton D2109 tube. The irradiated Kraton D2109 product exhibits higher break strength, lower elongation at break and dramatically improved high temperature (120 C) compression set that 10 excels Santoprene s performance' The irradiated Kraton D2109 compound yields a hardness of about SOA about 1000 psi of break strength, about 735% ultimate elongation and compression set of about 12% at about 120*C, Kraton D2109 pump tubing (0.25x0.3$ inches radiated for up to 8 passes of ebeam for effecting crosslinking is subjected to peristaltic pump test at 600 RPM using a standard head, IS The irradiated tubing is also tested for pump life at 600 RPM using an EZ load head. For the sake of comparison. lear R70-374 C-Flex size 1 tubing is also tested on E2 load. As can be seen rom rst in Table 3 below, XL-CFlex (Kraton D)2109)is pumped on the standard head for about 50 hours before failure. Surprisingly, the same tubing pumped for about 1000 hours on EZ load before failure In comparison, clear C-fex R70-374 is pumped for about 10 hours both 20 on standard and z load heads before failure, indicating that the design of the pump head is inconsequential Also the spallaion behavior of P70-374 is visually worse than irradiated Kraton D2109 (XL-CFlex) that show minimalpallation (as visually observed during the pump test) Table 3 Pump Life (hours) 0-Flex Std, EZ XL-CFlex (Kraton D2109) (translucent) 50 -1000 R<70-374 (clear) 10-10 R70-00 (opaque C-P pump tubin) 50 Not tested AdvantaFlex (milky but translucent) 100 Not tested EXAMPLE 2. Blends of EPDM with Saturated Styrenic Block Copolymers (SBC): 5 To make flexible tubing, blends of diene elastomers and styrenic thermoplastic elastomer with hardness ranging from Shore A of about 40 to about 90 can be used. Diene elastomers and styrenic thermoplastic elastomers used to demonstrate the concept of making crosslinkable blends by ionizing radiation are listed in Table 4. Four styrenic thermoplastic clastomers of different chemistries and physical properties are chosen Kraton G 1643Mand Kraton MD 6945 10 are resins produced by Kraton Polymers and are based on chemistry of polystyrene-block poly(ethylene-butylene)block-polystyrene (EBS). Hybrar 7125 has a chemical structure of polystyrene-blockpolyehyleneco-propylene) Vblock-polystyrene (SEiPS),;while Hybrar 7311 has a chemical structure of polystyrene-biock-polyethyienecojethylene-co-propylene)1block polystyrene (SEEPS) The Hybrar resins are supplied by Kuraray Co. Ltd- Kurashiki, Japan 15 EPDM is chosen to make the crosslinkable blends, In an embodiment, EPIDM resins made by the meatlocene polymerization technooy can be used in order to use common thenoplastic extrusion techniques to make tubing out of the blends. Unlike EPDM rubbers; which are completely amorphous and thus are in bale form at room temperature, the metallocene EPDM resins can be produced in pellet form due to some degree oftcrystallinity (typically in the range 20 of about 5% to about 20% as measured by DSC at 10"Cmin) existing in this type of materials. Nordel IP 4725 provided by Dow Chemical is he metiallocene EPDM resin selected to make crosslinkahle blends in this Example. Nordel IP4725 resin is in transparent pellet form and is reported by the producer to have about 12% rystallinity,
I
Table 4: Styrenic thermoplastic elastomer and EPDM raw material MFR, 00%- Tensile Hardness, MaterasModus, Strength, N1a GShore A a230*C M-a MPa Kraton G 1643M 18 5 4 15 6.3 Kraton MD6945 4 35 0U8 12,8 SBC Resin nI.
Hybrar 7125 4 64 L7 13,2 Hybrar 731 2 41 0.6 93 EPDM NordelIP4725 NA 66 L7 14,4 To make small batches of the blends, the polymtr components are mixed in a Brabender mixer at different ratios at about 200*C and about 60 rpm for about 5 rin. The resulting 10 mixtures are used to mold about Imm thick slabs in a Carver hot press, Dog bone testing specimens are cut out of the slabs for tensile rest FIG. I lists the mechanical and optical properties of blends befoe crosslinking It can be seen that transparent blends result for the EPDWKraton MD6945 and EPDM/Hybrar 731 I systems at all mixing levels, while translucent blends are obtained for blends of EPDM/Kraton G1643 aid EPDMlHybrar 7125. Hardness of 15 these blends ranges from Shore A of about 40 to about 70, which is within the desired range for flexible thermoplastc elastomer tubes, The elongation of the resulting blends is usually higher than about 1000%. The modulus of the bleeds goes generally between the two extremes of raw resins and the tensile strength of the blends is higher than those for the raw resins. To crosslink the blends, molded slabs are sent to E-BEAM Services Inc, in Lebaron., Ohio 20 for crosslinking treatment. 10 samples from the EPDM/Kraton MD6945 and EDM I/ Hybrar 7311 series are exposed to about 6.8Mrad (4 passes x .7 Mrd pass) e-beam of about 10 MeV. After e-beam treatment, no samples show any changes in clarity or yellowing due to degradation. Gel content tests are conducted by soaking a crosslinked sample in boiling he-ane for about 12 hrs and then measudng percentage ot nmnng solid conten in the sample. About 40% to 25 about 70% by weight gel content of the tota eight of the blend is measured for the c-beam treated blends of EPDM/Kraton MD6945 and 2DE M [Hybrar 7311. depending on their compositions. For untreaed FPDMs, thermoplasti elastomer samples, 0% gel content is found (completely dissolvedj.By comparing physical properties for crosslinked samples in FIG. 2 and results of corresponding un-crosslinked samples in FIG, li no significant changes are -14found in the c-beam treated blends in terms of hardness and modulus, slight increase in tensile modulus is found after e-beam treatment, while long ation of the crosslinked samples is seen to decrease by about 10% to about 20%. To check the influence of e-beam exposure to heat resistance of the blends, dynamic 5 mechanical analysis (DMA) is perfoned in the temperature range of about -80*C to about 200 0 C This test can determine the glass transition temperature, melting point of a thermoplastic by following changes in viscoeiastic behavior of a material with temperature, in a typical DMA test, the storage modulus measures how stiff and elastic the material is, the loss modulus indicates how fluid-like and viscous the material is and the loss tangent is the ratio of loss 10 modulus to storage modulus. For a polymer material to exhibit some heat-resistance so that no deformation occurs under its own weight when exposed to elevated temperatures, the storage modulus of the material is typically at least above about 1 MPa, while the loss tangent value is typically lower than about 0,25 MNa. Using these criteria, the maximum temperature that a thermoplastic elastotner material can be exposed to for short time, such as a steam sterilization 15 process, can be estimated, FIG. 3 shows the change of storage modulus and loss tangent with temperature for the blend of 50/50 Nordel IP4725/EPDM. Without crosslining by e-beam, storage modulus of the blend shows a sharp drop above about 100C, suggesting a melting and flow behavior, Storage modulus falls below about I MNa at about 95*C and loss tangent rises above about 0.25 at about 82"C, therefore the maximum short-term exposure temperature for this 20 blend will be around 80*C. After crosslinking by about 6.8 Mrad e-beam, the storage modulus of the 50/50 Nordel fP4725/EPDM blend displays a plateau from about 70*C and about 200*C. It does not fall below about 1 MPa until about 160"C. The loss tangent is not below about 0,25 MPa even at about 195*C. Therefore, this crossliaked blend is suitable for steam sterilization processes at both about 121 *C and about 135"C, 25 EXAMPLE 3. Tubing Madeof EPDM/styrenic theuoplastic elastomer blends: To make flexible tubing of the blends, mixtures of 50/50 Kraton C 1643M/Nordei IP45 with or without lubricating additives is compounded through a co-rotating twin-screw extuder and cooled by a water bath and cut into pellets. The resulting pellets are later fed into a single 30 screw extruder, which is equipped with a tubing die, A regular 3-zone screw is used for the tubing extrusion. The temperature profile ik set at about 280F, about 320"F and about 400* for three segments of the extruder. The adapter and die temperatures are set at about 405*F and
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about 4 15*F respectively. The polymer melt flowing out of the die is discharged into a submerging water tank for cooling, where the extudate is fmizen into a tubing shape. Internal air pressure, screw speed and pulling rate are combined to control the tubing dimensions and wal thickness. Translucent and flexible tubing with dimensions of 0.25" for ID and 0.375" for OD is 5 obtained through the above compounding and extrusion procedures. When an extruder with mixing screw sections is available, the twin screw compounding process can be omitted. Flexible tubing can be extruded from the blends by feeding dry blends of these resins directly into the extruder due to relatively high compatibility between EPDM and styrenic thermoplastic elastomers. 10 Tubing formulations and resuming tubing properties without c-beam crossiinking treatment are shown in FIG. 4 As low surface friction usually helps with pumping life in peristaitic pumping applications, three lubricants are evaluated at about 1% by weight addition level of the total weight of the blend. A 50% by weight silcone oil (vinyl tenninatcd polydimethyl siloxane) master hatch in EVA carrier resin is obtained from Dow Corning, Lubotene RLF4006 is a 15 silicone grafted low density polyethylene (LDPE) resin obtained from Optatch Corporation. Ampacet 102468 is a master batch of Eruamide in LDPE supplied by Ampacet Corporation, At about 1.0% by weight addition level of the total weight of the blend, all three lubricants show no significant effects on the kink resistance, which is measured by MBR (minimum bending radius), clarity and mechanical properties of the tube. Lubricants do increase pumping life of the tubing 20 when these tubes are used as the pumping segment in the standard head of a Masterfle peristaltic pump. The pumping tests are n at a speed of about 400 rpm in this study Without lubricant, the tubing could only operate about 2 hours due to wearing caused failures. By adding about 10% by weight of lubricant' pumping life of the tubing is ex tended up to about 6-1l hrs The tubes extruded fom blends of 50/50 Kraton G 1643M/Nordel IP45 are also 25 crosslinked by about 6. Mrads ebeam treatment. FIG. lists properties of the tubes after e beam crosslinking. Compared to the corresponding results in FIG. 4, It is clear that the -beam crosslinking process do not affect clarity, kink resistancehardness and tensile mechanical properties However, a very significant improvement can be seen in pumping life of the tubing. The unibricated tubing raises pump life from about hrs to about 24 hrs, while the lubricated 30 tubes improve their pump lives from about 6Il bra to the range of about i3-39 hrs, Furthermore, significant improvementin hea resistance of the tubes can be achieved through the e-beam cmssnking treatment. As lustrated bythe DMA results in FIG. 6, theuniubricated tubing of 50/50 Kraton i643M/Nordel IP45 can only withstand short exposure to about 8OC -16 while the e-beam crosslinked rube can be used at about I300C for shon term. Therefore, this crosslinked blend is suitable for steam steriNization processes at both about 121"C for a time of up to about 30 minutes and about 135*C for a time of up to about 20 minutes. EXAMPLE4: Blends of polyolef elastomers and diene elastomers 5 The following blends of polymers are mixed in different ratios at about 200*C to 230"C using a Brabender mixer. The restAing mixtures are molded into 2mm thick slabs and dog bone testing specimens aie cut out of the slabs for tensile and tear testing in accordance with ASTM 638 and ASTM 624, respectively. Properties can be seen in Table 5, Table 5 Sample Storage modulus Storage modulus Tg at Tan Delta (MPa) at -70'C (MPa) at OTC curve (*C) EPDM/EMA 1987 0,489 EPDMIEMA 1808 1,317 1750 4 e-beam passes EPDMIEMA 1796 L633 -1669 S c-beam passes EPDMMMA 1 35 1,505 16 12 10 Dynamic mechanical analysis of the EPDM/EMA blend with and without eteam irradiation can be seen in FIG. 7. 6.8 MRad (4 passes) of c-beam irradiation sufficiently crosslinks the EPDM/EMA blend, For instance, the PMA/EMA blend that has not been e beam irradiated is clearly not cosslinked as evidenced by the dramatic drop in storage modulus 15 as the temperature increases. Further. 6.8 Mrad passes of c-beamirradiation is sufficient to create a blend with heat resistance at temperatures greater than 100*C and in particular, steam sterilization processes at both about 120C for a time of up to about 30 minutes and about 1350C for a time of up to about 20 minutes.
Four samples are chosen to be extruded into tubing 0. 5625 inches OD X 0.375 inches ID for evaluation. The formulation and properties before and after e-beam treatment can be seen in Tables 6, 7, and 8, Table 6 Materials Grade Amount Hardness (Shore A) Elvax 360 0 0 75 PolyolefIn resin Versify 2400 100 g 68 Affinity EG8200 100 g 70 Engage 8180 l00g 63 EPDM Nordel IP4725 100 V 60 5 Table 7. Properties before e-beam treatment Material Shore A Young 100% 300% Tensile Elongation hardness modulus Modulus Modulus Strength ( (MPa) (Ma' (MPa) (MPa) EPDM/Elvax 77 113 1.5 19.3 1048 EPDM/Versify 6 08 13,9 1255 EPDw/Affnitv 6 6 ' 01 134 1232 EPDM/Engage 64 53k810 15,9 244 _____p 64__ 5.3 _ 1 1.0 __ __ __ _ is- Table 8, Properties after e-beam treatment Material Shore A Young 100% 300% Tensile Elongation hardness modulus Modulus Modulus Strength (%) (MPa) (MPa) (MPa) (MPa) EPDM/Ey ax 76 21 30 1 7 19.0 801 EPDMNIersify 60 6.9 1.7 09 11.1 982 EPDM/Affinty 6 7 68 20 1I 175 1081 EPDMlEngage 64 5S3 1 1 15.6 991 As seen in Tables 5-8, the crosslinking of the blend providesmaterials with advantageous properties, After c-beam irradiation, the material remains flexible The materials exhibit a 5 negligible change in Young modulus, 100% Modulus, 300% Modulus, and tensile strength after e-beam treatment. After c-beam treatment, the material shows a slight decrease in Elongation which indicates no chain scission of the material. Tear testing can be seen in FIG. 8. FIG. 9 is an illustration of the dynamic mechanical analysis (DMA) of a blend of EPDM/Affinity. The graphs show that there are no negligible 10 change in properties from 4 to 8 e-beam passe. is seen inFIG. 9, 6.8 Mrad (4 passes) of e beam irradiation i sufficient to create a blend with heat resistance at temperatures greater than 100*C and in particular, steam sterilization processes at both about 121tC for a time of up to about 30 minutes and about15C for a ime of up to about 20 minutes. Gel content testing as described above is performed on the materials of Tables 5 As seen 15 in FIG. 10. the gel content testing illustrates that there are no significant changes in the cros-link density between 4 and 8 e-beam passes. EXAMPLE 5: Blends of thermoplastic elastomers and ionomers. Blends of polymers are mixed in different ratios at temperatures ranging from about 300*F to about 4001F using a Brabender mixer. The blends are compression molded at a flat profile of 20 about 375*F into plaques for Shore A hardness, Young modulus (E), 100% Modulus elongation -19- (E-1 00%), elongation (s), tensile strength and tear strength testing, Shore A hardness ranges from about 50 to about 85, indicative of a soft, flexible material. Results can be seen in FIG. 1I Two samples are chosen to be extruded into tubing 0,385 inches OD X 0.255 inches ID for pump life evaluation, before and after et-bean treatment. Processability is good as there are no 5 problems with tube dimensions and tempemraure window. Pump life is tested at 600 RPM using an EZ load H pump head. Results can be seen in Table 9. Table 9. Pump life of styrenie thermoplastic elastomer/ionomer blend Material Average Pump life (hours) Surlvn 8320/SEEBS 01643 (50:50 bled) 190 Surlyn 8320/SEBS G164(3 50:50 blend) 4,83 4 pass E-beam Suryn 8320/1SES G 1645 (50:50 blond) 4.20 Surlyn 8320/SEBS G1645 (50:50 blend) 14.83 4 pass F-beam As seen in Table 9. irradiation of the tubes increases the pump life of both blends. 10 Note that not all of the activities described above n the general description or the examples are required, that a portion of a specific activity may not be required and that one or more further activities may be perfomied in addition to those described. Still further the order in which a t re listed are not necessarily the order in which they are performed. In the foregoing spcfcio.tecnet aebe ecie ihrfrneto specific 15 embodimients. Howiiever, on fodnr kl n thle artapeitsta aiu oiiain and changes can be made without departing from thi scope of the invention as set forth in the claims below. Accordingly, the specification and figuresare to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scopec ofivention. ,20~ As used herein, the terms "comprises," "comprising."includea "includig"has" "having" or any other variation thereof, are intended to cover a non-exclusive inclusion For example, a process, method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or 5 inherent to such process, method, article, or apparatus. Further. unless express ly stated to the contrary, "or" refers to an inclusive-er and not to an exclusive-or For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false or not present). A is false (or not present) and B is true (or present), and both A and B are true (or present). Also, the use of "a" or "an" a!employed to describe elements and components described 10 herein. This is done merely for convenience and to give a generalsense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise. Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments, However, the benefits, advantages, solutions to problems, and 15 any features) that may cause any benefit advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims. After reading the specification: killed artisans will appreciate that certain features are, for clarity, described herein in the context of separate embodiment, may also be provided in 20 combination in a single embodiment. Conversely, various features that are, for brevity described in the context of a single embodiment may also be provided separately or in any subcomination. Further, references to values stated in ranges include each and every value within that range. -21-