Pawling Custom Rubber and Plastic Products www.pawling.com/custom
Table of Contents Market Solutions................................4-7 Profile Constructs.................................8 Secondary Processes..............................9 Available Materials Thermoplastic...............................10 Thermoset..................................11 Tolerance Data..................................12 Glossary of Terms................................13 Standard Profiles and Stock Items...............14-16 www.pawling.com/custom
Market Solutions Pawling Engineered Products specializes in the custom design and manufacture of seals, gaskets, and other engineered rubber products. Advanced compounding, molding, extruding, and fabricating coupled with testing equipment and other techniques enable us to address your most demanding needs for highly durable and reliable rubber fabrications. VAB Double Bulb Door Seal Aerospace/Construction EPDM Detail: A large EPDM double bulb extrusion is used to seal the edges of the Vertical Assembly Building (VAB) Doors at the Kennedy Space Center in Cape Canaveral, Florida. This design allows for horizontal movement between the bulbs while the door is operational and provides dual sealing surfaces to keep the weather out. This part is extruded using our largest extruder and spliced in the field by our technical staff. Multi-Laminate Silicone Wing Flap Seal Aerospace/Defense Silicone, Fabric, and Polyester Detail: This part requires three unique materials to be compression molded into one compete gasket. The fabric outer layer is used to reduce the part s co-efficient of friction and to increase useful life. Silicone is used to handle temperature extremes and the rigid polyester base is used to prevent seal pullout from its housing. This seal is manufactured utilizing special molds and long presses to conform to the tight tolerances required for this application. 4 Pawling Custom Rubber and Plastic Products
Low Outgassing Expansion Joint Cleanrooms/Laboratories Silicone Detail: Ductwork enclosing a conveyor belt connects several clean rooms together, allowing for material movement between rooms. To address outgassing concerns and to account for slight movement in the ducting, Pawling designed a molded expansion joint made from a low outgassing silicone material (70643). Manufacture of this molded gasket is tightly controlled as any contaminants could compromise the clean room environment. One-Piece Zipper Gasket Transportation/ Construction Flexible PVC Detail: This zipper design replaces a traditional twopiece sealing system where a smaller gasket would be installed into the mating channel of a larger gasket. During installation, the gasket is placed onto the aluminum frame. The glass is then inserted into the inside channel and the zipper is pushed into place. This action locks the gasket and window together, which improves the part s effectiveness and ultimately lowers overall unit cost. www.pawling.com/custom 5
Market Solutions Roof Window Gasket Construction EPDM Detail: A unique, multi-faceted profile is spliced into a picture frame which serves as a seal between the roof window housing and frame. This part is manufactured using a high quality EPDM (E787M) with multiple sealing points, which reduces potential leakage. Using a dedicated work cell, Pawling manufactures these gaskets on demand through use of a unique molding and extruding process. Chemical Processing Seal Electronics/Semi-Conductor Processing Fluorosilicone Detail: Fluorosilicone is used to combat both high temperatures and aggressive chemicals. In this application, semi-conductor assemblies are treated in a large chemical bath. The fluorosilocone P-strip is used to seal the cover while the machine is operational. 6 Pawling Custom Rubber and Plastic Products
Fabric Reinforced Valve Seat Power Plant/Construction Natural Rubber Detail: Using our unique long press capabilities, Pawling manufactures an 8 (203 mm) wide, fully molded fabric reinforced expansion joint in long continuous lengths used for large pipe assemblies in power plants. Diameters approaching 8-10 feet (2438-3048 mm) are not uncommon. Depending on the requirements, this part can either be molded and spliced endless or can be step-cured into a complete gasket. Magnetic Sterilizer Gasket Medical/Sterilizers Silicone Detail: This sterilizer gasket withstands the rigors of high temperatures and latches the door by using magnets which are installed within the seal. This dual system combines the seal and latch into one unit, which simplifies design. Silicone is used to ensure the gasket maintains its effectiveness even under high temperatures. www.pawling.com/custom 7
Profile Constructs Dense - The majority of our parts are manufactured using dense materials. Dense profiles are resilient and extrudable whereas some other constructs can only be molded. Co-Extruded - Some applications require two types of material (usually having different durometers) to be joined together to form one part. A typical application involves a rigid component that acts as a retainer and a flexible component to act as a seal or bumper. Sponge - Sponge extrusions provide a soft, supple seal while optimizing material usage. Sponge profiles should not be used where compression set is important, because the part will eventually take a permanent set. Fabric Reinforced - Fabric reinforcement serves many purposes. Embedded fabric can strengthen a part s tensile strength which will allow it to withstand harsh applications. It also can be used on a part s surface to reduce coefficient of friction. Multi-Laminate - Multi-laminate designs are used in severe applications where part failure must be minimized. Aerospace applications use a multi-laminate construct of fabric, silicone, and polyester. The fabric reduces the part s coefficient of friction and the rigid polyester molded insert ensures that the part does not pull out of its retainer. 8 Pawling Custom Rubber and Plastic Products
Finishing Options Butt Splice - Butt Splices are the most common method to finish an extrusion into a gasket or seal. Some materials can be heat welded while others need to be vulcanized. Extruding and butt 7splicing is usually more cost effective than fully molding a part. Mitre Splice - Applications requiring a picture frame configuration can be spliced using a 45 degree mitre to form the frame. Molded Corners - When function and reliability must be optimized, corners are molded separately then butt spliced into a frame. This process moves the vulcanized splice away from the corner, which makes it stronger. Molded corners can be designed for gentle radii up to a full square. Notched Corners - Notched corners employ aspects of the mitre splice, but accomplish it without having to fully cut the extrusion. This method works particularly well with P-strip or J-seal designs (see page 14). Notching/Punching/PSA Application - Whether in-line or as a secondary operation, parts can be notched, punched, or PSA (pressure sensitive adhesive tape) can be applied to improve functionality. www.pawling.com/custom 9
Available Materials The appropriate thermoset and/or thermoplastic material is determined primarily by the function of your finished product. Durability, flexibility, and strength vary with the type of plastic or rubber chosen. We continue to broaden our range of material capabilities to better address our customers needs and keep a close eye on newly available materials. Please contact us if you have more specific requests. Our Sales Engineers will be happy to assist you. Thermoplastic Common Name/ASTM Designation TPE Alcryn TPU Flexible PVC Rigid PVC (TPV) (Vinyl) (Vinyl) Chemical Name Thermoplastic Melt Processible Thermoplastic Polyvinylchloride Polyvinylchloride Elastomer Rubber Urethane (Flexible) (Rigid) Hardness Range Shore A 30-90 40-95 60-85 60-96 Shore D 75-82 Rockwell Specific Gravity 0.87-1.35 1.10-1.17 1.14-1.19 1.37-1.45 1.33-1.41 Tensile Strength, psi 500-3000 1200-1900 3300-5600 1300-3000 6000-6600 Elongation% 210-600 200-500 620-870 240-430 Flexural Modulus, psi 0-54 200-500 n/a n/a 395,000-400,000 Notched Izod Impact, ft.lbs./in. 4-20 Abrasion Resistance VG VG E G VG Water Resistance E E G E E Ozone Resistance E E E E E Weather (UV) VG-E E F-G G G Acids E E F G G Alkali E E F G G Oil F E G F F Gas Permeability F G F F F Heat Aging G G G F F Low Temperature G E VG-E G F n-hexane G E G P P Xylene/Toluene (RT) F P P P P Methylethylketone (RT) G P P P P Trichloroethylene P P P P P Gasoline P G G-VG F F 2.5% Detergent Solution E E VG E E Antifreeze G G G P P Dioctyl Phthalate E n/a E P P Ethyl Alcohol VG G F G G E = Excellent VG = Very Good G = Good F = Fair P = Poor 10 Pawling Custom Rubber and Plastic Products
Thermoset Common Name EPDM or EP Neoprene SBR Nitrile Natural Butyl Silicone Fluorosilicone Fluorocarbon Rubber (Buna-N) Rubber Chemical Name Ethylene Chloroprene Styrene Acrylonitrile Natural Isobutylene Silicone Fluorosilicone Fluorocarbon Propylene Butadiene Butadiene Isoprene Isoprene *(Viton ) ASTM Designation EP CR SBR NBR NR IIR VMQ FVMQ FKM Hardness Range 40-90 20-80 40-90 50-95 50-70 40-75 40-80 40-70 70-90 Tensile Strength, psi >2000 >2000 >2000 >2000 >2000 >2000 >1200 >1200 >1400 Tear Resistance G G F F G G F P P Abrasion Resistance G-E VG G-E G E G P F G Compression Set G G G G E F VG E E Resilience Cold G G G F G P E G F Resilience Heat VG VG G G F VG E E E Radiation Resistance E G n/a P F-G G G E E Impermeability to Gases G G F G F E F F E Dielectric Strength E VG G P E G G G VG Electrical Insulation G-E F-G G P G-E G E E G Adhesion to Metals G E E E E G E E F-G Adhesion to Fabrics G E G G E G E E G Acid Resistance Mild Dilute E E F-G F-G P-F E E E E Strong Concentrated G G F-G F-G P G F G E Solvent Resistance Aliphatic Hydrocarbons P F-G P E P P P G E Aromatic Hydrocarbons P P P P P P P E E Oxygenated (Ketones, etc.) G P P P P G P F F Resistance To: Swelling in Lubricating Oil P G P VG P P P E E Oil and Gasoline P G P E P P F G E Animal Oils F F P E P F G E E Water Absorption VG G VG VG VG VG E E E Oxidation E VG F G P-F E E E G Ozone E VG P F P-F F-G E E E Sunlight Aging E VG P P P-F VG E E G Heat Aging VG G G G F-G G E E E Low Temperature VG G VG F-G G G E G F Flame P G P P P P F E E Vegetable Oils F G P G P F P E E Chlorinated Hydrocarbons P P P F P P P-F F G E = Excellent VG = Very Good G = Good F = Fair P = Poor *Viton is a trademark of E.I. Dupont Demours and Co. www.pawling.com/custom 11
Tolerance Data Because of rubber s variability from lot to lot, rubber manufacturers use these tolerances in order to ensure part conformity. Standard Extruded Cross Sectional Tolerances (Metric Units) 1 2 3 RMA Class High Precision Commercial Precision Drawing Designation E1 E2 E3 Dimensions (mm) Above Up To +/- +/- +/- 0 1.5 0.15 0.25 0.40 1.5 2.5 0.20 0.35 0.50 2.5 4.0 0.25 0.40 0.70 4.0 6.3 0.35 0.50 0.80 6.3 10 0.40 0.70 1.00 10 16 0.50 0.80 1.30 16 25 0.70 1.00 1.60 25 40 0.80 1.30 2.00 40 63 1.00 1.60 2.50 63 100 1.30 2.00 3.20 Standard Extruded Cross Sectional Tolerances (English Units) 1 2 3 RMA Class High Precision Commercial Precision Drawing Designation E1 E2 E3 Dimensions (inches) Above Up To +/- +/- +/- 0 0.06 0.006 0.010 0.015 0.06 0.10 0.008 0.014 0.020 0.10 0.16 0.010 0.016 0.027 0.16 0.25 0.014 0.020 0.031 0.25 0.39 0.016 0.027 0.039 0.39 0.63 0.020 0.031 0.051 0.63 0.98 0.027 0.039 0.063 0.98 1.57 0.031 0.051 0.079 1.57 2.48 0.039 0.063 0.098 2.48 3.94 0.051 0.079 0.126 Cut Length Tolerances for Unspliced Extrusion (Metric Units) 1 2 3 RMA Class High Precision Commercial Precision Drawing Designation L1 L2 L3 Dimensions (mm) Above Up To +/- +/- +/- 0 40 0.70 1.00 1.60 40 63 0.80 1.30 2.00 63 100 1.00 1.60 2.50 100 160 1.30 2.00 3.20 160 250 1.60 2.50 4.00 250 400 2.00 3.20 5.00 400 630 2.50 4.00 6.30 630 1000 3.20 5.00 10.00 1000 1600 4.00 6.30 12.50 1600 2500 5.00 10.00 16.00 2500 4000 6.30 12.50 20.00 4000 0.16% 0.32% 0.50% Cut Length Tolerances for Unspliced Extrusion (English Units) 1 2 3 RMA Class High Precision Commercial Precision Drawing Designation L1 L2 L3 Dimensions (inches) Above Up To +/- +/- +/- 0 1.60 0.03 0.04 0.06 1.60 2.50 0.03 0.05 0.08 2.50 4.00 0.04 0.06 0.10 4.00 6.30 0.05 0.08 0.13 6.30 10.00 0.06 0.10 0.16 10.00 16.00 0.08 0.13 0.20 16.00 25.00 0.10 0.16 0.25 25.00 40.00 0.13 0.20 0.40 40.00 63.00 0.16 0.25 0.50 63.00 100.00 0.20 0.40 0.63 100.00 160.00 0.25 050 0.80 160.00 0.16% 0.32% 0.50% Tolerance Tables and Glossary of Terms are courtesy of the Rubber Manufacturers Association (RMA). For more information, please visit their web site at www.rma.org. 12 Pawling Custom Rubber and Plastic Products
Glossary of Terms Abrasion Resistance - The resistance of a material to loss of surface particles due to friction. When high abrasion resistance is required, Polyurethane (either thermoset or thermoplastic) is preferred. Autoclave - A pressure vessel into which materials or articles can be placed and exposed to steam under pressure. It is commonly used to vulcanize carbon-based polymers, like EPDM, CR, Nitrile, and SBR. Butt Joint - A joint made in a rubber part before or after vulcanization by placing the two pieces to be joined edge-to-edge. A butt joint is preferred over a mitered joint as the butt joint is typically stronger. Compression Set The residual deformation after removal of the force which has subjected the specimen to compression. Compression set is a key factor when designing a part that will be compressed for long periods of time. Creep - The deformation, in either cured or uncured rubber under stress, which occurs with lapse of time after the immediate deformation. Durometer An instrument for measuring the indentation hardness of rubber; also, sometimes used as a synonym for hardness. For thermoset rubber and thermoplastic vulcanizate (TPV) materials, durometer is defined using the Shore A scale where the lower the value the softer the material. Elongation The maximum elongation prior to rupture. Friction - Produced from the interference of two surfaces brought together. Parts in light friction will slide along each other easily but as friction is increased sliding becomes more difficult. Microwave Curing - Heating a thick cross section uniformly is difficult using conventional ovens. Microwave technology however is not affected by dimensional considerations as the microwaves rapidly heat the insides and outsides of a profile simultaneously. A typical microwave extruder has a microwave unit at the end of the extruder to rapidly heat the extrusion and a HAV unit following to maintain temperature while vulcanizing. A significant benefit gained from microwave curing is that extremely long lengths can be achieved. Modulus The tensile strength recorded when the specimen is elongated 100%. For dynamic properties where the part will be stretched and compressed continually, a high modulus is preferred. Permeability - To permit passage of gas through the molecular structure of a given material. Materials with low permeability, such as Butyl or FKM, are preferred in vacuum applications. Tear Strength The maximum load required to tear apart a specimen; the acting substantially parallel to the major axis of the test specimen. For applications where the part may experience some shearing action, a high tear material is preferred. Tensile Strength The maximum tensile stress applied during stretching a specimen to rupture. The higher the tensile strength, the stronger the material. Vulcanization An irreversible process during which a rubber compound through a change in its chemical structure (for example, cross-linking) becomes less plastic and more resistant to swelling by organic liquids and elastic properties are conferred, improved, or extended over a greater range of temperature. Low Temperature Flexibility - The ability of a rubber product to be flexed, bent, or bowed at specified low temperature without loss of serviceability. Silicone is typically the polymer of choice when low temperature flexibility must be maintained. www.pawling.com/custom 13
Standard Cross Sections and Stocked Profiles P and J Seals 1 1/4 1/2 1 PR13540 (CR, VMQ) 1 1/4 1 1/4 PR13542 (CR, VMQ) 5/16 3 PR15782 (CR) 2 1/2 PR23333 (EP) 5/8 3/8 3/8 3/4 X21339 (CR) 1 1/8 PR13541 (EP, CR, VMQ) 1 3/4 1 1/4 PR28910 (NBR) 5/16 11/16 7/8 X21337 (CR) 1 1/2 4 PR18156 (CR) 1/2 6 PR15480 (EP) 1 1/2 1/4 1 1/8 2 1/4 1 3/4 PR19491 (FVMQ) PR5919 (CR) 3/8 1/2 4 7/8 X21338 (CR) 1 1/2 PR15415 (CR) 1/2 6 PR16448 (CR) 14 Pawling Custom Rubber and Plastic Products