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BASF's new Ultradur High Speed flows twice as far as standard PBT and cuts cycle times by up to 30% with no change in properties.
Solvay's new Supradel HTS sulfone polymer is said to have the highest heat resistance of any clear, amorphous resin.
Higher flow, higher heat, higher barrier, higher clarity, higher stiffness, lower durometer, lower smoke, lower odor—materials exhibits at the recent K 2004 show in Dusseldorf were stretching the bounds of processing and performance properties in all directions. There was ample news in engineering thermoplastics, styrenics, polyolefins, and even thermosets. (Many new materials not mentioned here were covered in our September show preview.)
The newest of the new
Wacker-Chemie of Germany (parent of Wacker Silicones in the U.S.) introduced the world's first "true silicone TPE. Its new Geniomer family is a single-phase silicone/urea copolymer, in which the silicone soft block (more than 90% of the composition) provides elasticity while the urea hard block provides strength and heat resistance. (This is quite different from the relatively new TPSiV family of TPEs, in which crosslinked silicone rubber particles are dispersed in a nylon or other engineering thermoplastic matrix.)
Geniomer, like some TPU materials, forms physical crosslinks when it cools from the melt. These crosslinks are reversible when reheated, providing true thermoplasticity. Geniomer can be processed by all thermoplastic methods. Four grades are currently available (see table) with hardnesses from 40 to 60 Shore A. Price is a little higher than thermoset LSRs.
Geniomer is highly transparent. It contains no catalysts, free volatile silicone components, fillers, or plasticizers. Its chemical purity is said to be suitable for medical uses, and its clarity suggest automotive applications (it is being tested as a soundproofing sheet for laminating on car windows). It possesses the inherent qualities of silicones—uv resistance, gas permeability, and good release and slip properties. It is paintable and can serve as a flexible bonding agent between plastics and glass or metal. It can also be used at low levels (0.1% to 0.2%) as a processing aid for other polymers to improve flow, low-temperature flexibility, and water repellence.
Another brand-new TPE is being brought to market by two companies. It is a triblock copolymer of styrene-isobutylene-styrene (SIBS). It is a 100% saturated polymer and therefore very heat- and light-stable, according to Kaneka of Japan, whose new Sibstar family is commercially available for around $2.75 to $2.95/lb. Its higher price than other SBCs suits it to niche applications. A prime example is seals, owing to the resin's excellent gas-barrier (similar to thermoset PIB rubber) and mechanical-damping properties. SIBS is also inherently softer (without added oils) than other styrenic TPEs of equivalent styrene content, Kaneka says. The company sees potential uses in soft-touch overmolding of closures.
A developmental line of SIBS is still in the pilot-plant stage at BASF in Germany. Its Oppanol IBS (initially a 35 Shore A version) is expected to find use mainly in blends with PE, PP, and PS. (PIB rubber does not blend well with plastics). Applications could include medical and food packaging such as seals on closures and wine corks. PVC replacement is one possibility, though SIBS blends will be more costly.
|WACKER'S NEW GENIOMER SILICONE TPE|
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Terpalex is a new terpolymer of nylons 6, 66, and 12 from Ube Industries. It was developed for food packaging and is said to provide high transparency plus deep-drawability and greater shrinkability than other nylons. It has clarity and gloss comparable to nylon 612 and a slightly lower melting point than nylon 612 or 6/66 copolymer. It also boasts excellent processability in blown and cast film and good pinhole resistance. Monofilaments are another potential market.
Sulfone sets new heat mark
Another truly new polymer at K was an engineering thermoplastic said to offer the highest heat resistance of any transparent amorphous polymer. Supradel HTS from Solvay Advanced Polymers is a brand-new aromatic sulfone polymer with a glass transition temperature of 265 C (509 F) and HDT of 255 C (491 F) at 264 psi. These are in the same range as Solvay's Torlon polyamide-imide, but the latter is opaque and needs post-curing to achieve maximum properties. Supradel HTS permits clear applications that formerly were limited to opaque crystalline materials like glass-filled PEEK.
Supradel HTS can be injection molded (and probably extruded) at temperatures around 275 to 280 F, though it has fairly high viscosity, like Solvay's Radel sulfones. The material is inherently flame resistant, hydrolysis resistant (it can withstand high-temperature steam), and is relatively tough, like Radel A polyethersulfone. Unlike thermoplastic polyimides, it reportedly requires no annealing and the melt is more thermally stable. At this early stage, it is yellow in color. Price is similar to that of PEEK ($33 to $40/lb).
Meanwhile, Solvay has reduced the yellow color of polysulfone to approach the clarity of polycarbonate. Its new low-color Udel P-1700 HC is nearly water white. Radel R poly phenylsulfone also now has lower color. New Radel R-5800 TR comes in a series of transparent colors suitable for color-coded medical uses. Also new is Radel R 7000, a clear grade for aircraft interiors that can be extruded into large sheets.
Other news in high-temperature resins includes high-flow PEEK grades from Victrex for thin-wall and highly filled parts. Both Victrex 90P (powder) and 90G (pellets) have an 84 MFR, which is more than twice that of standard PEEK. They also provide a 60% improvement in spiral flow over standard products. The material is targeted for thin-wall parts such electrical connectors, where PEEK has been unsuitable due to mold-filling difficulties.
Meanwhile, ultra-high-purity Victrex 450 U002 is claimed to meet the strict requirements for extractables in clean rooms, chemical processing, and electronics. The new product, which contains less than 1 ppm of metals, is aimed at semiconductor processing components such as focus rings, fasteners, chamber insulators, and seals.
Chevron Phillips Chemicals recently introduced a new member of its Xtel PPS alloy family for high-temperature wire coating. Xtel XE3200 is aimed at 150 C continuous-use temperatures in automotive, railway, marine, industrial, and specialty wire markets. It is halogen-free but has an LOI of 35. The alloy also boasts high chemical resistance, good colorability, low density (1.15 g/cc), and ability to achieve very thin coatings at high processing speed on standard equipment capable of running at 300 C (572 F). No crosslinking is needed.
Chevron Phillips also reports that long-term field tests confirm the effectiveness of Ryton PPS liners for FRP piping to convey hot, corrosive chemicals such as caustic soda (50% NaOH) at 110 to 130 C. The liner is extruded of neat HMW PPS—either in the form of pipe or sheets that are post-formed and seamed into a tube. The liner is reinforced by filament winding with glass and thermoset polyester. Liner sections can be joined by IR butt fusion or rod welding. The main competitor for PPS in this application is PVDF, but PPS boasts 50° C higher heat resistance and better resistance to caustic soda.
In fluoropolymers, Arkema (formerly Atofina) came out with two new Kynar PVDF grades. Kynar ADX is a novel reactive series of homo- and copolymers that adhere to metals, certain rubbers, and functionalized polyolefins (allowing coextrusion of PE/PVDF structures). Kynar Flex "Ultra Low Smoke PVDF is designed to meet the "Limited Combustible specs of NPFA 255 tests for plenum wire and cable. This resin reportedly shows zero flame spread and almost no visible smoke in this test.
The second generation of Durethan EasyFlow nylon 6 from Lanxess reportedly boosts flow by about 22%. It allows lower melt temperatures, which shorten cycle times. Tests show that auto intake manifolds can be molded at a melt temperature of 250 to 285 C versus 280 to 313 C for a standard nylon 6. As a result, cycle time is reduced 15%. High flow also creates more design options for production of thin-wall components with good surface quality.
A similar achievement in high flow for PBT was claimed by BASF, whose new Ultradur High Speed reportedly flows at least twice as far on spiral-flow tests as standard Ultradur B4300 grades (see photo). The new "rheology-modified version is said to cut cycle times by up to 30% without any sacrifice in properties, thanks to an organic additive that is soluble in the melt but forms separate nano-scale domains when the melt cools. BASF technicians say the viscosity curve is of the same shape as normal, just shifted downward. In one test application, a sun roof was molded successfully with four of its eight hot-runner nozzles blocked off, producing fewer weld lines. In other tests, BASF was able to drop the melt temperature by 30° C and injection and holding pressures by 50%. High Speed versions of Ultradur B4300 come with 10%, 20% and 30% glass. Later, BASF plans to use Ultradur High Speed in PBT/ASA and PBT/PET blends.
In the same vein, Lanxess introduced Pocan DP 1105 Easy Flow PBT, which boasts good impact strength. Other new PBTs include Pocan hydrolysis-resistant KU2-7111 from Lanxess and its new Pocan DP2004 for electrical housings. The latter has good toughness and is halogen-free. It meets Glow Wire specs and has a CTI of 600 V.
Nylons get more muscle
Rhodia unveiled Technyl SI "super-impact grades, a new range of modified nylon 6 with an exceptional impact/stiffness balance. These materials offer 20% more impact than other high-impact nylons together with equal or higher stiffness. A key market is power tools, where manufacturers have had to compromise between high impact and stiffness. Other markets include machine components, sporting goods, and personal-protection equipment.
Rhodia is offering three unfilled grades and two with 30% glass. They cost 10% to 15% more than typical impact-modified grades.
Rhodia also launched Technyl Force resins, a new series of long-glass nylons for injection molded auto parts. The high flow of the matrix resin reportedly results in lower shear, thereby enhancing fiber-length retention and impact strength. Technyl Force is also said to deliver processing benefits such as faster cycles, lower injection pressure and clamping force, and reduced processing temperature. Four grades have glass loadings from 30% to 60%.
Similarly, DuPont has come out with so-called "superstructural resins aimed at metal-replacement applications and other demanding uses. These include its first long-fiber grades and others with high loadings of short fibers. Three Zytel nylon 66 grades and one Zytel HTN nylon 6T come with 40% to 60% long glass, while Zytel CDV805 toughened nylon 66 has a mix of long glass and short carbon fibers. Also new are five Zytel HTN grades with 35% to 55% short glass.
Lanxess has extended the effort of Bayer (its former parent) in metal/plastic hybrid technology for auto front ends with the introduction of a new nylon 6 with 60% glass. This highly rigid Durethan grade has tensile modulus of 2.9 million psi, more than twice that of standard 30% glass-filled nylon 6. Even at 170 C, the new material has tensile modulus of 971,500 psi. Lanxess says the rigidity of the nylon allows for more plastic than metal to be used in the hybrid construction. The nylon can be formed more easily than metal in complex areas, reducing production costs. The material, which boasts strong creep resistance, is being considered for under-hood uses such as intake pipes, valve covers, and oil pans.
Also new from Lanxess is Dure than DP 1803/10 H3.0, a 10% glass-filled nylon 6 for circuit breakers. It boasts good flow in thin walls, very good electrical properties, and halogen-free flame retardancy that meets European Glow Wire standards (GWIT of 775 C and GWFI of 960 C).
New Durethan DP 2802/30 nylon 66 with 30% glass from Lanxess is aimed at household appliances. It meets Glow Wire standards without halogen or phosphorus and has a CTI of 600V.
EMS-Grivory has introduced the first in a new generation of FR nylon 66 for the electrical/electronics industry. Grilon TSG-30/4 V0 with 30% glass uses no halogen or red phosphorus, and reportedly meets the new EC Waste Electrical and Electronic Equipment Directive, which will take effect in August. It boasts excellent electrical properties (600V CTI) and a UL 94V-0 rating at 0.8 mm. Elongation at break is 4.5% after moisture conditioning.
A new laser weldable nylon 6 from DSM contains 30% glass and is said to produce strong bonds along complex geometries. UltraLas K224-HWXG6 has high laser transparency.
Arkema (formerly Atofina) has several new specialty nylons aimed at auto under-hood and fuel-system components. Rilsan M-BESN Black P 212 CTL is a conductive nylon 11 that is said to be the first to meet SAE J2260 standards for fuel systems (surface resistivity below 106 ohm/sq). Also meeting SAE J2260 is Rilsan M-AESN Black P 212 CTL, a conductive, easy-flow nylon 12 for fuel tubes.
Also new are two grades designed for tubing to carry hot diesel fuel at more than 100 C. Rilsan M-AESN Black P 210 TL is a nylon 12 alloy with high heat-aging resistance. Rilsan M-BESN Black P 210 TL is a developmental nylon 11 based on new polymerization technology that makes it stiffer at elevated temperatures and more flexible in the cold.
The first Rilsan grade dedicated to automotive cooling lines is Rilsan M-AESN Black P 110 TL, a nylon 12 alloyed with a small amount of nylon 11. That combination softens the nylon 12, boosting impact resistance at -40 C plus resistance to water/glycol mixtures and hot air (130 C). Upcoming developments for cooling lines are a nylon 11 for temperatures above 120 C and a multi-layer system for above 130 C.
An unusual nylon compound designed for purging engineering thermoplastics was introduced by BASF. Ultramid Ultraclean 290 is unfilled and non-abrasive. It softens but does not melt and is described as having a "sponge-like action to scrub resins from processing machines. It can be used to speed purging of any resin at up to 280 C (536 F) and is said to perform well in narrow hot-runner channels.
TP elastomers get softer
Zeon Chemicals launched the first blow molding grade of its new Zeotherm TPV, consisting of crosslinked acrylic rubber in a nylon 6 matrix. Zeotherm 120-90B has a continuous-use temperature of 150 to 175 C, which meets the demands of auto under-hood applications, where fewer heat shields are being employed, says Zeon. Typical uses include air ducts, boots, and bellows.
Radici Plastics continues to expand beyond its flagship nylon materials. It has expanded its TPE range with five grades of copolyester-ether TPEs called Heraflex E. They range in hardness from 35 to 77 Shore D and will serve auto applications such as CVJ boots, air-brake systems, and airbag doors.
Three new entries in Santoprene TPVs were announced by Advanced Elastomer Systems (AES). The most dramatic is a soon-to-be-available line that promises up to 25% faster injection molding cycles due to faster set-up in the mold. This is a result of higher crystallization temperatures and is said to involve no change in properties.
Also new is a softer grade, Santoprene X8211-25 with 25 Shore A hardness, and a dry and silky feel. It's suitable for consumer products and packaging. The softest grade before now was 35A.
Third, AES came out with Santoprene grades for outdoor electrical applications such as battery cable. They meet European Union environmental rules because they contain virtually no lead, traces of which are commonly present in antimony flame retardants.
Other news in TPVs and TPOs comes from Solvay Engineered Polymers. Luna 10 is a TPV with good scratch and abrasion resistance and a soft touch that is aimed at extruded and thermoformed dashboard covers. It is a U.S. development, as is Platon TPO, a developmental platable TPO whose availability is currently limited by customer agreements.
Another relatively new series of TPOs and TPVs is the Excelink line from JSR Corp., Specialty Elastomer Div. TPOs (Excelink 3000 Series) come in hardnesses of 29A to 65A, as well as a 52A foamable grade (Excelink 3500B). TPVs include high-flow injection grades (Excelink 1000 series) of 20A to 80A hardness and oil-resistant grades (Excelink 2000 series) of 64A to 84A hardness.
The latest from Kraiburg TPE GmbH is Thermolast K compounds based on SEBS for automotive interiors that have very low odor emissions (no "new car smell) and very low fogging. They cover a range of Shore 30 A to 90 A. Other new Thermolast K compounds for medical uses (30A to 80A) are sterilizable by steam or ethylene oxide. They have been certified USP Class VI. And a new antimicrobial grade for shower trays and handles, gaskets, hoses, and membranes prevents growth of bacterial or fungal slime when wet. It also meets FDA specs.
Brand-new from Ube is Ubesta XPA, a new nylon copolymer elastomer with a nylon 12 hard segment and a reportedly unique polyether soft segment. This polyether amide for injection molding and extrusion of tubing, film, and monofilament reportedly exhibits excellent chemical and hydrolysis resistance and outstanding flexural fatigue resistance down to -40 C. It also has high transparency and low density (1.01 g/cc), and it is plasticizer-free.
Arkema is working with Alveo AG of Switzerland to develop foams made from Pebax polyether-block-amide TPE. "Pebaxfoam products have good moisture permeability, low-temperature flexibility, softness, uv and aging resistance, and high friction coefficient. They are aimed at shoe insoles, heel inserts, grips, and gaskets.
News in styrenics
ABS resins tailored for low-temperature impact were introduced by Dow Plastics. The Magnum Shield series is said to maintain toughness down to -30 C for applications in recreational vehicles, snowmobiles, ski boxes, and luggage. These resins reportedly provide super-high impact without sacrificing the aesthetic and processing advantages of mass ABS.
Lanxess launched a new ABS series called Lustran Ultra, which is expected to move ABS into high-tech applications, replacing other thermoplastics and blends. The first material, platable Lustran Ultra 4000 PG, is based on Lanxess' Novodur P2MC grade but has 10° C higher heat resistance. This means components can be electroplated in shorter cycles than PC/ABS. In addition, the new material is claimed to distort significantly less in pickling baths than a standard ABS. The material is targeted for auto trim such as grilles, along with household items and sanitary components. Coming additions to the Lustran Ultra series will include high-impact grades, low-emission materials for auto interiors, and a high-heat version.
BASF exhibited the first blow molded products made from its weatherable Luran S ASA. The first commercial uses are extrusion blow molded parts for a hospital bed, though BASF also showed non-commercial parts made by injection-blow molding.
Dow announced a developmental PS that combines high toughness, high clarity, high heat resistance, and high hoop strength for use in form-fill-seal food packaging. Based on new rubber technology, this resin reportedly eliminates the need to blend PS with expensive block copolymers or to coextrude with a glossy cap layer.
A new HIPS from Total Petrochemicals (formerly Atofina) is aimed at thin-wall injection molding. Grade 6541 replaces older 6531, providing the same high flow plus higher impact and Vicat temperature. Also new is grade 3450 HIPS for extrusion/thermoforming and injection molding. It offers the same heat resistance as older grade 3351 but with higher flow (7 MFR).
PP gets stiff & tough
Dow Plastics is bringing out the second generation of its Inspire "performance polypropylenes. Its first Inspire grade in the U.S. was a high-melt-strength (HMS) resin aimed at blown film. Now it is adding two homopolymers with high stiffness. Inspire 213 is designed for thermoformable sheet, where it reportedly permits downgauging by more than 10%. It also boasts improved clarity and gloss, superior heat resistance for microwaving and hot filling, plus faster cycles. New Inspire 215 for injection molding of thin-wall food containers also offers improved gloss and heat resistance, as well as superior top-load strength and faster cycles, Dow claims. In filled compounds, it reportedly provides high gloss and potential for lightweighting.
Later this year, Dow plans to combine stiffness and toughness in new stiff impact copolymers for rigid packaging. Later plans include the launch of high-clarity PP for bottles.
Basell revealed new details on its brand-new Softell family of ethylene-propylene copolymer alloys that boast unusual softness while retaining good mechanical strength. Softell has Shore hardness as low as 75 A, vs. 85 A minimum for standard PP. Basell sees potential for replacing leather, EPDM, and SEBS and applications in automotive, roofing, fibers, medical films, soft-touch consumer disposables, grips, and bottles.
Still about a year away from commercialization are novel Metocene metallocene-based PPs that combine aspects of random and heterophasic copolymers. These "Random HeCo resins boast good impact strength plus transparency and flexibility. Potential applications are injection molded DVD boxes and thick films.
Among several new PP resins from Borealis are Borcom "microcomposites for auto interior and appliance parts. They contain a proprietary mineral "micro-filler of up to 10 micron size that improves properties at half the typical 20% loading of standard fillers sized at 20 to 50 microns. The result is said to be weight savings from 8% to 24%. Special compounding technology is used to obtain a fine dispersion of the micro-filler. New grades include Borcom WG 140AI for auto interiors and appliances, WE 007E for "zero-gap auto exterior trim, and another grade for high-impact auto exterior parts.
Borealis also introduced five Advanced Borseal terpolymers of ethylene-propylene-butylene designed for BOPP films. Their improved heat stability reportedly cuts down on fumes and die deposits while also improving gloss (especially when metalized) and reducing haze. The resin comes with or without slip and/or antiblock.
Also new is Borpact SG930MO, a clarified PP for frozen-food packaging that's said to combine toughness with clarity. There's also BorECO BA122E for non-pressure pipe, which boasts an improved balance of toughness and stiffness. Its flex modulus is >275,500 psi. And new PP1112 compound reportedly overcomes dimensional stability problems that have prevented PP from competing with PBT in fiber-optic cable.
New Beta-PPR RA7050 is a random copolymer said to offer a "step change in design strength for hot- and cold-water pipe. Its design strength of 5 MPa (725 psi) at 70 C for 50 yr is more than 50% higher than the current standard of 3.21 MPa (465 psi). As a result, pipes can be made thinner than before, saving resin while allowing larger I.D. for less pressure drop.
Three new Exxtral filled PP impact copolymers for automotive are available from ExxonMobil. Exxtral BMT 301 provides high scratch resistance for interior parts. It boasts the stiffness of medium-impact PP with the toughness of high-impact grades. Also new is Exxtral CMU 101, which contains only 10% talc, while offering the same stiffness as 20%-talc grades. The result is 17% higher impact and 7% lower density (0.98 g/cc), though scratch resistance is lower. Two brand-new Exxtral grades are BMT 131 and 132, whose impact/stiffness balance has been tuned for bumpers.
Arkema (formerly Atofina) came out with a line of long-glass PP compounds called Pryltex. All grades are chemically coupled and heat stabilized. UV stabilized and impact-modified versions are available, as are natural, black, and colors. Pellet lengths are 12 or 25 mm (0.5 or 1 in.), and glass levels range from 20% to 50%, except for concentrates with 50% and 65% glass.
Total Petrochemicals, Arkema's sister company (also formerly part of Atofina), has two new high-clarity random copolymers for blow molding. One is PPR 7225 for injection stretch-blow. It boasts good toughness and a wide processing window. The other is PPR 3221 for extrusion blow. It is clarified for high transparency, even when extruded at low temperatures. It also boasts a wider processing window and fewer mold deposits than competing grades.
PEs for film, wire, pipe
A new HDPE from ExxonMobil is designed specifically for blending with LLDPE or mLLDPE in films. Its HTA108 grade (0.961 g/cc, 0.7 MI) increases stiffness without sacrificing clarity or toughness (impact, tear, and puncture resistance), according to the company. Its 1% secant modulus is 181,250 psi MD, 246,500 psi TD. The resin is said to be relatively non-splitty, low in gels, and easy to process.
Also new from ExxonMobil is an LLDPE tailored for silane-crosslinked low-voltage power cable insulation. New LL 400EL (0.924 g/cc) reportedly has a unique combination of easy flow (3.6 MI) and rapid crosslinking with both one-step and two-step silane processes.
Borealis says its new Borcoat HE3450 bimodal HDPE is the first HDPE suitable for coating oil pipelines, which previously used MDPE or PP. The new black grade combines easy processability for high outputs and optimum thickness control with the toughness of HDPE. On the new pipeline from Baku, Azerbaijan, to Turkey, the new grade is the outer layer in a three-layer construction that starts with epoxy primer and a Borcoat ME0420 MA-grafted PE tie layer.
Easier processing is said to characterize second-generation metallocene PEs from Total Petrochemicals (formerly Atofina). Newest additions to this series are at least seven ER grades of mMDPE and mHDPE (0.930 to 0.960 g/cc) for cast film. Applications include hygiene film and special multi-layer stretch films where no cling is required on one side. One grade, ER 2299 (0.940 g/cc, 4 MI), is said to produce very soft films with only 10% LDPE added.
Total is also launching a new generation of mPEs for rotomolding. The first grade is M 3581 UV, available in pellet and powder. It is said to combine the superior mechanical properties of mPE with easy grinding, fast sintering, fast densification, easy air removal, and no need for slow cooling. It also boasts outstanding gloss.
In barrier resins, Eval Europe introduced a new EVOH that features four to 10 times the orientation of typical grades. In thermoforming, Eval SP reportedly offers a wider processing window—close to that of PP and PS—for deep and unusual shapes. And in shrink film, it can be oriented on conventional tenter-frame or double-bubble lines. Eval SP is also claimed to offer strong delamination resistance in multilayer PET bottles. Four grades with different barrier levels are expected to penetrate new applications including shrink bags, casings, and deep-draw packaging.
Arkema introduced its first grafted polyolefin to bond PP to metal foil. Orevac 18370 is aimed at laminated films to package candy and snacks. In the outer layer of cast and metalized PP film, this tie layer reportedly provides five to 10 times greater adhesion to the metalized layer.
Wacker-Chemie introduced its first fluorinated LSRs to compete with resins from GE Advanced Materials and Dow Corning. Aimed at gaskets and o-rings, Elastosil FLR is much more resistant to oils and fuels at under-hood temperatures up to 180 C (356 F). It reportedly processes like standard LSR, is fast cycling, and does not stick to molds. Initial grades of 40 and 60 Shore A are said to show good compression set and no surface tack.
Wacker also came out with a new "self-adhesive two-part LSR with much improved mechanical properties. It is an extension of the Elastosil LR 307X family, which adheres to many thermoplastics, thermosets, elastomers, and metals (but not hardened steel molds). They can be used in overmolding without primers. New transparent and FDA-compliant Elastosil LR 3471 has 50 Shore A hardness, tensile strength of 1336 psi, 500% ultimate elongation, and tear strength of 7733 psi.