Elastomeric cyclic olefin copolymers.
Topas COC grades are distinguished by glass transition temperature and molecular weight. The glass transition temperature (Tg) depends on the mole percent of norbornene. The typical commercial Tg range is between 33[degrees]C and 170[degrees]C. COC has many key property attributes, including, but not limited to, exceptional moisture and aroma barrier, chemical resistance, transparency, purity, stiffness and strength (ref. 1).
Elastomeric cyclic olefin copolymer (E-140) is an expansion of the Topas COC product technology platform. E-140 is a largely amorphous polymer with low level crystallinity. E-140 is a random copolymer without hard or soft segments or dispersed rubber phase morphologies. Toughness and impact resistance combined with excellent barrier, transparency, low dielectric and high purity enables E-140 to compete favorably with existing elastomers.
E-140 has high purity and enjoys broad regulatory compliance. E-140 complies with FDA Food Contact Notification (FCN) #1104 for many U.S. food contact applications. E-140 can be used in the manufacture of food contact articles that will be in contact with aqueous, acidic, low alcohol (up to 15%) and dry foods under conditions such as hot filled or pasteurized above 150[degrees]F (65[degrees]C) through frozen storage with no thermal treatment in the container.
Monomers and additives are listed in the EU Plastics Regulation 10/2011/EC (PIM-Plastic Implementation Measure). The product is listed in FDA Drug Master File #12132 and Device Master File #1043. It meets EU and U.S. Pharmacopeia for PE and PP. E-140 has passed USP Class VI and ISO 10993 protocols, including cytotoxicity studies. The product has been added to Health Canada's listing of acceptable polymers for use in food packaging applications. E-140 is not recommended or supported for use in implant applications.
E-140 is an extremely pure and simple polymer formulated and manufactured without controversial ingredients. E-140 does not use in its process or formulations plasticizers, including phthalates; RoHS substances; bisphenol A; CONEG heavy metals, including lead, cadmium, chromium VI and mercury; vinyl chloride monomer or polymer; halogens including chlorine and fluorine; fluorochemicals or fluoropolymers, including PFOA; flame retardants, including brominated compounds; California Proposition 65 substances; SARA 313 substances; ozone-depleting chemicals; and natural rubber or latex compounds.
Material properties (refs. 2-8)
In addition to its unmatched purity, E-140 offers many valuable features and benefits, namely oxygen and moisture barrier, good tensile properties, low specific gravity, excellent optical properties and low dielectric properties.
Barrier properties are clearly an advantageous feature of E-140. Specifically, oxygen and water vapor permeability are superior to many elastomers. Rigid cyclic olefin copolymers (COC) are not noted for their oxygen barrier property relative to widely used polyamide and ethylene vinyl alcohol. However, COC is better than polyolefins. As shown in table 1, oxygen permeability of linear low density polyethylene (Attane 4201) is 279 cc-mm/[m.sup.2] day atm measured at 23[degrees]C; 50% RH (ASTM D3985 and related protocols), about ten times higher than 24 cc-mm/[m.sup.2] day atm for COC (Topas 8007). E-140 is higher, 118 cc-mm/[m.sup.2] day atm. This value is similar to those of copolyester elastomers, 37 cc-mm/[m.sup.2] day atm (Riteflex 663) and 130 cc-mm/[m.sup.2] day atm (Ecdel 9966). Yet, E-140 has superior oxygen permeability relative to many other elastomers. Oxygen permeability of TPV (Santoprene 201-87), polybutadiene TPE (JSR RB830), SEBS (Kraton G-1652) and SIS (Kraton D-1101) is 434, 550, 1,095 and 1,717 cc-mm/[m.sup.2] day atm, respectively.
Rigid COC has noteworthy moisture vapor barrier, not matched by most thermoplastic materials. As shown in table 2, water vapor permeability of linear low density polyethylene (Attane 4201) is 0.5 g-mm/[m.sup.2] day measured at 38[degrees]C; 90% RH (ASTM F1249 and related protocols), about five times higher than 0.09 g-mm/[m.sup.2] day for COC (Topas 8007). Water vapor permeability of E-140, 0.4 g-mm/[m.sup.2] day, is not as low as COC. This value is similar to TPV (Santoprene 201 87), 0.2 g-mm/[m.sup.2] day. As with oxygen permeability, E-140 has superior moisture barrier relative to many elastomers. Water vapor permeability of polybutadiene TPE (JSR RB830), copolyester elastomer (Ecdel 9966), SIS (Kraton D-1101) and ether type TPU (Estane 58237) is 10, 19, 257 (23[degrees]C) and 550 g-mm/[m.sup.2] day, respectively.
E-140 has many useful mechanical properties summarized in table 3. As with many polyolefins, E-140 specific gravity is less than 1.0 g/cc. At 0.94 g/cc, E-140 is similar to the olefin based TPV (Santoprene 201-87), 0.96 g/cc; but much lower than 1.01 g/cc for SBS (Styrolux 684D) and 1.13 g/cc for copolyester elastomer (Ecdel 9966). Yield advantage can be significant for low density elastomers. Water absorption is very low, barely detectable for E-140, which is not a surprise given its low water permeability. Performance and dimensional stability of E-140 is expected to be unchanged in high humidity and water saturated environments. E-140 is very tough and durable. Total energy to failure, as measured by instrumented dart impact (ASTM D3763), for E-140 and SBS (Styrolux 684D) is 33 and 16 ft.-lb., respectively. E-140 is transparent. Total haze of 5-mil blown film is about 1.3%, similar to that of copolyester elastomer (Ecdel 9966) and SBS (Styrolux 684D). Low haze can be achieved in thicker, 2-3 mm, injection molded articles, but tool finish and quality influence results. Tensile properties of E-140, specifically tensile strength and elongation at break, are similar to TPV (Santoprene 201-87), SBS (Styrolux 684D) and copolyester elastomer (Ecdel 9966). However, like most elastomers, these properties are strain rate dependent. Tensile strength at break and hardness map show the tensile strength and durometer A and D hardness relationship for generic elastomeric type, including TPU, TPV, TPO and TPS. Ultimate tensile strength of E-140 is rate dependent. At slower 50 mm/minute strain rate, tensile strength about doubles due to strain hardening. At 500 mm/minute, strain hardening occurs, but to a lesser degree. Hardness of COC E at durometer A 89 lies in the middle of the range for most elastomers.
As shown in table 4, dielectric properties of E-140 are excellent. Dielectric strength is the maximum voltage required to produce dielectric breakdown in the material. Dielectric strength (ASTM D149, 500 V/second; short) is 4,000, 820 and 150 V/mil for E-140, TPV (Santoprene 201-87) and copolyester elastomer (Ecdel 9966), respectively. Dielectric constant quantifies the ability of an insulating material to store electrical energy. Dielectric constant (relative permittivity) and dissipation factor (ASTM D150, IEC 60250 and ASTM D2520) are measured across a broad range of frequencies at 23[degrees]C; 50% RH. Electrical applications where high capacitance is needed typically favor those materials with lower dielectric constant. Dielectric constant of E-140 is very low, 2.2 measured at high (microwave) frequencies between 1 and 10 GHz. Dielectric constant of SBS (Styrolux 684D) and TPV (Santoprene 201-87) are slightly higher, between 2.4 and 2.5, but are measured at much lower frequencies. Dielectric constant of copolyester elastomer (Ecdel 9966) is much higher between 3.9 and 3.8, measured at low 1 and 10 kHz frequency. Dissipation factor measures the inefficiency of an insulating material. Dissipation factor values for these elastomers follow a similar trend with dielectric constant.
Dynamic mechanical analysis (figure 1) shows four major thermal transitions for E-140, each related to the structure of this mostly amorphous random olefinic copolymer. E-140 has extremely low ductile-brittle transition temperature of <-90[degrees]C, corresponding to the glass transition of amorphous polyethylene. Ethylene-norbornene glass transition temperature, as shown by the step change in slope of the elastic modulus, occurs at about 6[degrees]C. As shown in table 4, E-140 has a Vicat softening point of 64[degrees]C, which corresponds to the onset of a second step change in slope of the elastic modulus. This is lower than the 86[degrees]C and 170[degrees]C softening point for SBS (Styrolux 684D) and copolyester elastomer (Ecdel 9966), respectively. Melt temperature of E-140 crystalline polyethylene and perhaps ethylene-norbornene phases occur at 85[degrees]C. These thermal transitions are nicely illustrated by tensile strength measured at five temperatures at 500 mm/minute strain rate. E-140 retains ductility at -25[degrees]C and -50[degrees]C, with elongation at break in excess of 200%. Sharp tensile strength at yield peaks are 30 MPa (4,350 psi) and 38 MPa (5,500 psi), respectively. E-140 shows a tensile yield point below ethylene-norbornene glass transition. At 0[degrees]C and above, tensile yield is not evident and the extent of strain hardening becomes less at 50[degrees]C, near the softening point. Electron beam crosslinking (figure 2) can greatly extend the useful upper temperature range for E-140 fabricated products. DMTA of 100 micron (4-mil) E-140 films, treated at 150-250 kV and 50-100 kGy, show increased storage modulus more than 150[degrees]C beyond the crystalline melting point. Higher energy and radiation dosage increases crosslinking and practical stiffness. E-beam crosslinking does not adversely change color or haze.
E-140 can be melt processed and fabricated into useful articles by all common thermoplastic techniques. These include mono, multi and nano-layer film and sheet extrusion, profile extrusion for hose and tubing, injection and co-injection molding, calendering, single and twin screw compounding for filler and polymer blending, multi-layer extrusion blow molding and foams. Melt process temperatures are similar to those of LLDPE, between 190[degrees]C to 260[degrees]C. Melt flow rate, measured at 190[degrees]C and 260[degrees]C, 2.16 kg, is 2.7 and 11.0 dg/ minute, respectively.
The unique combination of mechanical, barrier, optical, electrical and thermal properties of E-140 has lead to many successful commercial applications in a few short years. These applications include, but are not limited to, tubing (figure 3) and hoses, caps, gaskets, films and bags, impact modifiers, polyolefin compatibilizer, food, medical and pharmaceutical packaging, cryogenic components and dielectrics. Creativity inspired by E-140 will enable many exciting new applications in the future.
This article was originally presented at SPE's Thermoplastic Elastomers 11th Topical Conference in September 2014.
(1.) R.R. Lamonte, "Stiffer, thinner packaging films with improved sealing using cyclic olefin copolymers," presented at 10th Worldwide Flexible Packaging Conference, Amsterdam, The Netherlands, November 2000.
(2.) Liesl K. Massey, Permeability Properties of Plastics & Elastomers, 2nd, Plastics Design Library, 2003, pp. 436-437, 440, 444-445, 448-449.
(3.) Laurence W. McKeen, Film Properties of Plastics & Elastomers, 3rd, Plastics Design Library, 2013, pp. 193, 342-344, 346, 349.
(4.) Styrolux 684D technical data sheet, Styrolution, UL Prospector, June 2014.
(5.) Ecdel 9966 technical data sheet, Eastman Chemical Company, UL Prospector, June 2014.
(6.) Riteflex 663 technical data sheet, Celanese Corporation, UL Prospector, June 2014.
(7.) Attane 4201G technical data sheet, Dow Chemical Company, UL Prospector, June 2014.
(8.) Santoprene 201-87 technical data sheet, ExxonMobil Chemical, UL Prospector, June 2014.
by Paul D. Tatarka, Topas Advanced Polymers
Table 1--oxygen permeability of elastomers and polymers (23[degrees]C; 50% RH) Grade Material type Supplier Oxygen permeability (cc-mm/ [m.sup.2] day atm) 8007F-04 COC Topas Advanced Polymers 24 Attane 4201 Ultra LDPE Dow Chemical 279 E-140 COC elastomer Topas Advanced Polymers 118 Riteflex 663 Copolyester Celanese Corporation 37 elastomer Ecdel 9966 Copolyester Eastman Chemical 130 elastomer Santoprene TPV ExxonMobil Chemical 434 201-87 JSR RB830 Polybutadiene Japan Synthetic Rubber 550 (TPE) G-1652 SEBS Kraton Polymers 1,095 D-1101 SIS Kraton Polymers 1,717 Table 2--water vapor permeability of elastomers and polymers (38[degrees]C; 90% RH) Grade Material type Supplier Water vapor permeability (g-mm/ [m.sup.2]day) 8007F-04 COC Topas 0.09 Attane 4201 Ultra LDPE Dow Chemical 0.5 E-140 COC Topas 0.4 Santoprene TPV ExxonMobil Chemical 0.2 201-87 JSR RB820 Polybutadiene Japan Synthetic 7 (TPE) Rubber JSR RB830 Polybutadiene Japan Synthetic 10 (TPE) Rubber Ecdel 9966 Copolyester Eastman Chemical 19 elastomer G-1652 SEBS Kraton Polymers 83 (23[degrees]C) Estane 58315 Ether type TPU Lubrizol Advanced 250 Materials D-1101 SIS Kraton Polymers 257 (23[degrees]C) Estane 58237 Ether type TPU Lubrizol 550 Advanced Materials Table 3--mechanical properties of elastomers Grade Topas E-140 Type COC elastomer Supplier Topas Advanced Polymers Property Test method Units Specific gravity ASTM D792 g/cc 0.94 Hardness ASTM D2240 Durometer A 89 Water absorption ASTM D570 % <0.01 (24 hours, 23[degrees]C) High speed puncture ASTM D3763 Peak force lbs. 270 Total energy ft.-lb. 33 Tensile stress at ASTM D6328 psi 2,800 break (500 mm/min.) Elongation at break ASTM D6328 % 700 (500 mm/min.) Haze ASTM D1003 % 1.3 (5-mil) Ecdel 9966 Santoprene Styrolux 684D 201-87 Copolyester TPV SBS elastomer ExxonMobil Styrolution Eastman Chemical Property Specific gravity 1.13 0.96 1.01 Hardness 95 93 68 (durometer D) Water absorption 0.4 -- 0.07 (24 hours, 23[degrees]C) High speed puncture Peak force -- -- -- Total energy -- -- 16 Tensile stress at 3,200 2,550 3,800 break (500 mm/min.) Elongation at break 400 580 250 (500 mm/min.) Haze 1.0 (5-mil) -- 1.5 Table 4--thermal and electrical properties of elastomers Topas E-140 COC Grade elastomer Type Topas Supplier Advanced Property Test method Units Polymers Ductile-brittle transition ASTM D746 [degrees]C <-90 Glass transition DSC/DMTA [degrees]c 6 Vicat softening ASTM D1525 [degrees]c 64 Melting temperature DSC/DMTA [degrees]c 85 Dielectric strength ASTM D149 V/mil. 4,000 (500 v/sec.; short) Dielectric constant ASTM D150, -- (1 kHz hour, 23[degrees]C) IEC 60250, -- (10 kHz hour, 23[degrees]C) ASTM D2520 -- (1 MHz hour, 23[degrees]C) -- (1 GHz hour, 23[degrees]C) 2.2 (5 GHz hour, 23[degrees]C) 2.2 (10 GHz hour, 23[degrees]C) 2.2 Dissipation factor ASTM D150, (1 kHz hour, 23[degrees]C) IEC 60250, -- (10 kHz hour, 23[degrees]C) ASTM D2520 -- (1 MHz hour, 23[degrees]C) -- (1 GHz hour, 23[degrees]C) 0.00026 (5 GHz hour, 23[degrees]C) 0.00033 (10 GHz hour, 23[degrees]C) 0.00030 Ecdel 9966 Copolyester Santoprene Styrolux elastomer 201-87 684D Eastman TPV SBS Property Chemical ExxonMobil Styrolution Ductile-brittle transition <-75 -54 -- Glass transition -3 -- -- Vicat softening 170 -- 86 Melting temperature 205 -- -- Dielectric strength 150 820 -- Dielectric constant -- 2.4 -- (1 kHz hour, 23[degrees]C) 3.9 -- -- (10 kHz hour, 23[degrees]C) 3.8 -- -- (1 MHz hour, 23[degrees]C) -- -- 2.5 (1 GHz hour, 23[degrees]C) -- -- -- (5 GHz hour, 23[degrees]C) -- -- -- (10 GHz hour, 23[degrees]C) -- -- -- Dissipation factor (1 kHz hour, 23[degrees]C) 0.02 -- -- (10 kHz hour, 23[degrees]C) 0.02 -- -- (1 MHz hour, 23[degrees]C) -- -- 0.00080 (1 GHz hour, 23[degrees]C) -- -- -- (5 GHz hour, 23[degrees]C) -- -- -- (10 GHz hour, 23[degrees]C) -- -- --
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|Author:||Tatarka, Paul D.|
|Date:||Jun 1, 2015|
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