Materials

With Spiratex's ram and screw extrusion technologies, your custom extrusion can be manufactured using virtually any thermoplastic polymer. We've worked with plastic material suppliers for decades on the development of extrusion grade polymers. The following list gives some examples of plastics we use to extrude into your specific tube or profile. (Keep in mind additives such as UV stabilizers, flame retardants, and glass fiber can be added to enhance the properties of your custom design). For questions involving custom blends and alloys or technical assistance, please e-mail us.

ABS (Acrylonitrile Butadiene Styrene)

ABS is an amorphous material, like RPVC, and is naturally ivory in color. It is made of three components: Acrylonitrile, Butadiene, and Styrene, with varying degrees of each.

Acrylonitrile gives the material chemical resistance and heat stability.
Butadiene gives it mechanical toughness and impact strength.
Styrene provides rigidity.

ABS is used in many different areas because of its versatility. It is used anywhere from appliances (refrigerator door liners and crisper drawers) to automotive instrument panels and trim. The automotive sector is a large consumer of ABS since it can be used on both the interior and exterior of the vehicle. ABS is known for its good processability and is easy to fabricate. It is desired for its high gloss and can be colored to fit your needs.

Acetal or Delrin (POM)

Acetal is a highly crystalline material and is an opaque white color in its natural state. Acetal is available as both a homopolymer and copolymer; where both properties provide excellent mechanical, chemical, and electrical properties. They are able to do so over wide temperature ranges over long periods of time. Acetal is known for its friction and wear properties as one of the strongest, stiffest plastics available. Unlike nylon, acetal will not change dimensionally in a humid environment. It provides superior creep and fatigue resistance. Additives can be used in acetal as well. It requires protection from UV by additives, such as carbon black, in order to keep it from degrading with prolonged exposure.

Acetal is found in many plumbing applications such as impellers, pumps, showerheads, nozzles, etc., typically where water exposure is high. It is also commonly found in industrial and electrical applications such as gears, cams, switches, buttons and handles. Spiratex has the experience extruding profiles, filled and unfilled, for various industries.

Nylon (Polyamide)

Nylon was originally developed to be used as a fiber and its natural color is white or ivory. It has many uses and is the material of choice for applications involving high service temperature, low coefficient of friction, chemical resistance, abrasion or wear and toughness. Nylon comes in several variations ranging from 6, 6/6, 11, 12, filled (glass or moly), alloys, and more.

Nylon's largest applications include gears, cams, bearings, guides and housings. Nylon tends to absorb water from the environment over time thus affecting its dimensional stability. Spiratex has a great deal of experience with nylon tubing, spiral wrap and profiles with many of the profiles being used in the conveyor industry. Some grades can be used in food contact applications when used in accordance with FDA standards.

Polycarbonate (P/C)

Polycarbonate is known for being one of the toughest thermoplastic materials available. It is easily extrudable, has excellent clarity and can be colored to fit your needs. P/C is ideal in high continuous use temperatures (up to 250° F) but is limited when exposed to high heat and humidity for long periods of time.

Polycarbonate has excellent outdoor weathering properties. It is found in applications such as windows, shield, and eye glasses, where you want to replace glass with an indestructible material. P/C also lends itself to many secondary processes like welding, solvent bonding, hot stamping, printing, and can be machined and reshaped by using heat.

Polyethylene (P/E)

Polyethylene is a member of the olefin family and can be produced with linear and branched molecular chains. High density polyethylene (HDPE), linear low-density, high molecular weight high-density and ultrahigh-molecular weight are made up of linear molecular chains. Low-density polyethylene has branch molecular chains and unlike other polyethylenes, is produced under very high pressure. This method produces molecular chains with various side chain lengths or branches. The difference between the two is the degree of crystallinity.

The density of the polyethylene determines its properties. The higher the density, the more stiff the material. The higher density yields a higher softening point with higher tensile and creep resistance. Unfortunately, with a higher density other properties are lost. This means lower impact strength, elongation, and flexibility. By changing the density or molecular weight, a wide variety of properties can be attained.

HDPE is used anywhere from small tubing up to large pipe (used for natural gas, sewer pipe, or drainage lines). It can be made into custom profiles and used to coat wire and cable. A large amount of HDPE is used in blow molding which produces things like fuel tanks and containers.

LDPE is puncture and tear resistant and is used mostly for films and bags due to its low crystallinity. It is used for coatings to help with heat sealability and moisture barriers.

UHMWPE is quite different from most other polyethylenes and therefore has a dedicated material description.

Polypropylene (P/P):

Polypropylene is a crystalline material from the same family of polymers as polyethylene, the polyolefins. Polypropylene has very similar characteristics to polyethylene where they are resistant to water, have good chemical resistance and dielectric properties. The biggest difference between them is that P/P's relative density runs in the 0.90 range as opposed to P/E which is in the 0.940 to 0.965 range. Polypropylene has a higher service temperature and is more rigid and resistant to environmental stress cracking.

The two most common types of polypropylene are homopolymer P/P and random copolymer P/P. Homopolymer P/P is typically used in fibers and filaments and is found in packaging as a film due to its water barrier characteristics. The random copolymer P/P is a tougher, more impact resistant part due to a flexible ethylene component that is added to the molecular structure. The copolymers are typically found in interior or exterior trim pieces or parts for furniture.

Polypropylene can be difficult to bond, has poor weatherability, and is normally flammable. Its properties can be enhanced by adding fillers such as glass, talc, or a flame retardant.

Polyurethane (TPU)

Spiratex is a custom extruder of all thermoplastics but our capabilities with thermoplastic polyurethane (TPU) deserve some special attention. Spiratex has always been at the forefront of TPU extrusion; particularly since the early 1970's when many flexible PVC hoses and tubes began being replaced with polyurethane. We have worked with all the major TPU suppliers over the years such as BASF, Lubrizol (formerly Goodrich), Dow and Bayer.

TPU is known for its overall toughness and flexibility at low temperatures and has outperformed PVC in many demanding applications. People saw the opportunity in seals and industrial belting to replace rubber and PVC profiles with TPU. We have numerous years of experience extruding both tubing and profiles using TPU.

There are many variations of TPU's to choose from and the grade you use depends on your application. Our engineering department will work with you to choose the polyurethane that best fits your needs. The first step is to determine the environment your product will be used.

All TPU's can be divided into two categories, esters and ethers. Ester based TPU's are the tougher of the two but break down when they're exposed to water for long periods of time. Esters are ideal for industrial applications such as belting or roller covers since they're more resistant to chemicals and oils. Ether based TPU's do not degrade in water but they are considered not as tough.

Another feature of all TPU's is the degree of hardness available. The hardness is measured as the durometer of the material and most common TPU's fall into the A-scale, ranging from 55A to 98A. 98A TPU is roughly equivalent to 55 on the D-scale and polyurethane can go as high as 75D. Once into the D-scale, TPU becomes very stiff. Most uses of TPU generally require material in the 80A to 90A range.

Additional properties of TPU are high tensile strength, cut resistance, high wear and abrasion resistance and sound dampening. Additives can be combined with TPU to enhance the above properties along with adding others, such as UV protection. Spiratex has a history of test running new TPU designs. We have extruded pieces reinforced with aramid fiber and tungsten filled TPU. Look at our products and see the multitude of parts that can be made with thermoplastic polyurethane.

PVC (Rigid and Flexible)

Rigid PVC (RPVC) is an amorphous plastic that is used extensively in the construction industry because it is rigid, dimensionally stable and has good resistance to weathering and corrosion. Most RPVC is used for window profiles, home siding and piping. RPVC can be used in situations where flame and electrical resistance is needed.

RPVC is a fairly low cost material and has a higher density than many other similar plastics. It has a relatively low thermal decomposition temperature but can be improved by alloying it with other thermoplastics. We have had success co-extruding RPVC profiles with FPVC or TPU. RPVC usually comes to us clear but can be colored to fit your needs.

The amount of plasticizer controls the hardness of the PVC and by adding more of it, the PVC becomes softer and more flexible. The hardness, or durometer, is measured using the Shore A-Scale. PVC with a hardness of 50A-90A is considered flexible. Flexible PVC (FPVC) is usually clear but can be colored to fit your needs.

FPVC is used in medical tubing, general tubing and seals. It has great sound and vibration dampening properties in addition to chemical resistance properties. FPVC is comparatively cheap versus similar TPU parts.

Santoprene (TPV)

Santoprene is a thermoplastic vulcanizate (TPV) resin that is an in-situ mixture cross linking EPDM rubber and Polypropylene. It is an elastomer that combines the attributes of vulcanized rubber (flexibility and low compression set) with the processing characteristics of thermoplastics. Environmental aging resistance, electrical properties and liquid resistance are about the same as EPDM and it can replace EPDM in certain applications.

Santoprene TPV Advantages

  • Harsh-environment performance
    • Parts made from Santoprene TPV's offer a constant service temperature range from 60°C to 135°C (-81°F to 275°F) with no cracking or tackiness. Excellent heat aging combines with good resistance to many acids, bases and aqueous solutions.
  • Soft-touch aesthetics
    • The dry silky feel of grips, handles and knobs made with Santoprene TPV's add appeal and cost-effective market value to products.
  • Broad range of flexibility
    • Santoprene TPV's range from flexible 35 Shore A to tough 50 Shore D. General purpose grades are suitable for most applications. FDA-compliant, NSF-listed and medical grades are also available. Flame-retardant grades meet UL requirements.
  • Easier design for Parts
    • Design tolerances can be two to three times more precise than with EPDM or polychloroprene rubber. This enables product designers to create parts with thick or thin walls and to simplify multi-part designs. Several grades that bond with ETP's, nylons, metals and various other polyolefins are available creating co-extrusion options which save costs through parts consolidation and design flexibility.

Thermoplastic Polyester Elastomer (TPE)

TPE's combine the properties of high performance elastomers and flexible polymers. They are high strength materials known for their ability to take repeated flex cycles and their resistance to many chemicals and oils. TPE's have high impact strength even at low temperatures and have high heat resistance up to 300°F. Just like thermoplastic polyurethanes, there is a large range of durometers, or hardness, to choose from. TPE's hardness ranges are typically in the "D" scale unlike TPU's which tend to stay in the "A" scale. There are many uses for TPE's such as belting, tubing, fasciae, bushings and gears. The most common industries are automotive, sporting goods, power tools, conveyor, cable and fluid power.

Thermoplastic Rubber (TPR)

There are a few different types of thermoplastic rubbers available. Thermoplastic rubber can replace many different rubber components since it's easy to extrude and eliminates the vulcanization process. Different companies have taken different approaches to producing the product. Some are made up of a highly vulcanized rubber and plastic mixture where the plastic is typically a polypropylene and the vulcanized rubber component is evenly mixed throughout the melt. There are also melt-processable rubbers which can be extruded and have the same characteristics of actual rubber.

TPR's come in different durometers ranging from 55A to 50D. They have excellent resistance to fatigue, high tear strength and good fuel and oil resistance. TPR is a great fit when looking to replace seals, tubing, hoses, spacers, bumpers and other rubber parts.

UHMW/PE (Ultra High Molecular Weight Polyethylene)

U.H.M.W.P.E. symbolizes Ultra High Molecular Weight Polyethylene which means the average molecular weight is greater than 3,100,000 as defined by ASTM D4020 standards for UHMWPE. UHMWPE is a linear polyolefin which is made up of extremely long chains of polyethylene that all align in the same direction. Polymers are large molecules built from monomers and UHMWPE's monomer is ethylene. Resin with a molecular weight greater than 3,100,000 is well above the molecular weight of most typical polymers, which are between 10,000 and 1,000,000, hence earning the term UHMWPE. Commercially offered resins are available from 3-6 million molecular weight. Resins in the 3.1-4.5 range have the best combination of impact strength and abrasion resistance. The molecular weight of UHMWPE must be approximated using the solution viscosity procedure found in ASTM D4020.

UHMWPE is commonly referred to as UHMW PE, UHMW-PE, UHMW/PE, Ultra-high, and sometimes UH. There are several different trade names for UHMWPE. "ULTREX" is the Spiratex Company's trade name for extruded UHMWPE.

For Polyethylene molecular weight classification, the following guidelines can be used:

HDPE (High Density Polyethylene) 100,000 - 400,000
HMWHDPE (High Molecular Weight High Density Polyethylene) 500,000 - 1,999,999
VHMWHDPE (Very High Molecular Weight High Density Polyethylene) 2,000,000 - 3,099,999
UHMWPE (Ultra High Molecular Weight Polyethylene) 3,100,000 +

Properties of UHMWPE:

  • Excellent abrasion resistance
  • Excellent impact strength (the highest of any plastic)
  • Superior chemical resistance even to the most aggressive chemicals
    • Greater chemical resistance than HDPE, polyurethane, steel, polyacetal and nylon.
  • Water repellent highly resistant to hydrolysis
  • Biologically inert
  • Excellent dielectric & insulting properties
  • Stress crack resistant

UHMWPE is frequently used in the material handling industry, including food contact surfaces, as it is acceptable under FDA and USDA guidelines. It is used in lead-acid battery separators, medical implants, filters and a wide variety of other applications.

UHMW/PE with Custom Additives

In addition to standard UHMWPE, the Spiratex Company has years of experience modifying base resin with the addition of additives to alter performance properties to suit custom applications. A few are:

16020 ULTREX Enhanced Conductivity UHMWPE is achieved by adding a superconductive carbon black which lowers the surface resistivity range to 105 - 109. The dispersed superconductive additive allows electron movement across the part itself. The product is black in color and is not FDA compliant. This is the most effective option for dealing with conductivity and static charges.

16026 Ultrex Ultraviolet (UV) Stabilized UHMWPE is used to slow or prevent attacks by ultraviolet (UV) radiation from the sunlight by dispersing UV stabilizers in the polymer prior to extruding. This attack is known as UV degradation and can be a problem in products that are highly exposed to sunlight or in some cases artificial sources. Continuous exposure for long periods of time is a more serious problem than intermittent exposure since the attack is dependent on the extent and degree of exposure. Our UHMWPE UV Stabilized product, known as 16026 ULTREX, is black in color and has optimal protection against UV attack. This material is not FDA compliant.

16050 ULTREX UHMWPE with antistatic additives reduces the buildup of static electricity caused by the triboelectric effect. The additives leach onto the surface of the material and absorb moisture from the air. The molecules of an antistatic additive have both hydrophilic and hydrophobic areas, similar to those of a surfactant. The hydrophilic side interacts with air moisture and binds water molecules, whereas the hydrophobic side interacts with the surface of the material. The effectiveness of this option is dependent on the humidity of the environment and the leaching of the additive. This material when used in accordance with the applicable FDA polyolefin regulation 21 CFR 177.152 meets the requirements of 2.1 and 2.2 for food contact applications.

16303 Lubricated ULTREX UHMWPE was developed to have additional lubricity in the form of a continuously regenerating surface film. This is achieved by incorporating proprietary additives into the base UHMWPE polymer which are extruded under high pressure. This homogenous blend of UHMWPE polymer and normally solid lubricants with a grease yield produces products that are self-lubricating, slowly releasing lubricant at temperatures developed in ordinary use. The extruded product exhibits excellent dimensional stability, good wear resistance and a surface that is not oily to the touch. Dimensional changes are inconsequential and other desirable properties are unaffected. The standard color for this material is gray when used in accordance with the applicable FDA polyolefin regulation 21 CFR 177.1520 meets the requirements of 2.1 and 2.2 for food contact applications.

Materials Comparison Chart

Outdoor Weathering Wear Resistance Coefficient of Friction Impact Strength Rigidity Heat Distortion Temperature
ABS Fair Low Medium Moderate Excellent Good
Polystyrene Poor Poor Medium Poor Excellent Good
CAB (Butyrate) Excellent Low Medium Low Excellent Good
PVDF Good Fair Low Good Good Excellent
UHMWPE Good Excellent Very Low Excellent Good Good
HDPE Fair Good Low Good Good Good
LDPE Fair Fair Medium Good Fair Fair
LLDPE Fair Fair Low Good Good / Fair Good
PVC Flexible Excellent Fair Medium Varies Varies Varies
Polycarbonate Excellent Good Medium Good Maximum Good
Polyurethane Excellent Excellent Very High Varies Varies Varies
Nylon Good Good Very Low Good Varies Varies
TPEs Fair Excellent High Fair Varies Varies

Polymer Abbreviations

Following is a list of industry accepted abbreviations of various polymers. The Spiratex Co. has had extrusion experience with the highlighted materials.

Abbreviation   Polymer Name
ABA acrylonitrile-butadiene acrylate
ABS acrylonitrile-butadiene styrene terpolymer
ACS acrylonitrile-chlorinated polyethylene styrene terpolymer
AMA acrylate maleic anhydride terpolymer
AMMA acrylonitrile-methyl methacrylate
APO amorphous polyolefin
AS acrylonitrile styrene copolymer
ASA acrylonitrile styrene acrylate
BMC bulk molding compound
BMI bis maleimide
CA cellulose acetate
CAB cellulose acetate butyrate
CAP cellulose acetate proprionate
CN cellulose nitrate (celluloid)
COC cycloolefin copolymer
COP copolyester thermoplastic elastomer
CPE chlorinated polyethylene
CPVC chlorinated polyvinyl chloride
CTA cellulose triacetate
CTFE chlorotrifluoroethylene
DAP diallyl phthallate (thermoset)
EAA ethylene acrylic acid copolymer
EC ethyl cellulose
ECTFE ethylene chlorotrifluoroethylene
EMAC ethylene-methyl acrylate copolymer
EnBA ethylene n-butyl acetate
EP epoxy
EPDM ethylene propylene diene monomer rubber
EPM ethylene propylene copolymer rubber
EPR ethylene propylene rubber
EPS expandable polystyrene
ETFE ethylene tetrafluoroethylene
EVA ethylene vinyl acetate
E/VAC ethylene/vinyl acetate copolymer
EVOH ethylene vinyl alcohol
FEP fluorinated ethylene propylene
FRP fiber reinforced plastic
HDPE high density polyethylene
HIPS high impact polystyrene
HMC high strength molding compound
HMWHDPE high molecular weight high density polyethylene
I ionomer
IPN interpenetrating polymer network
LCP liquid crystal polymer
LDPE low density polyethylene
LLDPE linear low density polyethylene
LPE linear polyethylene
MA maleic anhydride
MABS methyl methacrylate/ABS copolymer
MBS methyl methacrylate butadiene styrene terpolymer
MDPE medium density polyethylene
MF melamine formaldehyde
MP melamine phenolic
NBR nitrile butadiene rubber
OSA olefin modified styrene acrylonitrile
P phenolic
PA polyamide (nylon)
PAA poly acetic acid
PAI polyamide-imide
PAEK polyaryletherketone
PAK polyester alkyd
PAL polyanaline
PAN polyacrylonitrile
PARA polyaryl amide
PAS polyarylsulfone
PB polubutylene
PBAN polybutadiene acrylonitrile
PBD polybutadine
PBI polybenzimidazole
PBN polybutylene napthalate
PBS polybutadiene styrene
PBT polybutylene terephthalate
PC polycarbonate
PC/ABS polycarbonate/acrylonitrile butadiene styrene blend
PCL polycaprolactone
PCT polycyclohexylene terephthallate
PCT-G glycol modified polycyclohexyl terephthallate
PCTFE polymonochlorotrifluoroethylene
PE polyethylene
PEBA polyether block amide or polyester block amide
PEEK polyetheretherketone
PEI polyetherimide
PEK polyetherketone
PEKEKK polyetherketone etherketone ketone
PEKK polyetherketoneketone
PEN polyethylene napthalene
PEO polyethylene oxide
PES polyethersulfone
PET polyethylene terephthalate
PET-G glycol modified polyethylene terephthalate
PFA perfluoroalkoxy
PI polyimide
PI polyisoprene
PIB polyisobutylene
PIR polyisocyanurate
PMAN polymethactylonitrile
PMMA polymethylmethacrylate (acrylic)
PMP polymethylpentene
PMS paramethylstyrene
PO polyolefin
POM polyoxymethylene (acetal)
PP polypropylene
PPA polyphthalamide
PPC chlorinated polypropylene
PPC polyphthalate carbonate
PPE polyphenylene ether
PPI polymeric polyisocyanate
PPO polyphenylene oxide
PPOX polypropylene oxide
PPS polyphenylene sulfide
PPSU polyphenylene sulfone
PPT polypropylene terephthalate
PS polystyrene
PS-b-PI polystyrene/polyisoprene block copolymer
PSO,PSU polysulfone
PTFE polytetrafluoroethylene
PTMT polytetramethylene terephthalate
PU,PUR polyurethane
PVA polyvinyl alcohol (sometimes polyvinyl acetate)
PVAc polyvinyl acetate
PVB polyvinyl butyryl
PVC polyvinyl chloride
PVCA polyvinyl chloride acetate
PVDA polyvinylidene acetate
PVDC polyvinylidene chloride
PVDF polyvinylidene fluoride
PVF polyvinyl fluoride
PVK polyvinyl carbazole
PVOH polyvinyl alcohol
PVP polyvinyl pyrrolidone
SAN styrene acrylonitrile
SB styrene butadiene
SBR styrene butadiene rubber
SBS styrene butadiene styrene block copolymer
SEBS styrene ethylene butylene styrene block copolymer
SI silicone
SIS styrene isoprene styrene block copolymer
SMA styrene maleic anhydride copolymer
SMC sheet molding compound
SMMA styrene methyl methacrylate
SMS styrene/a-methyl styrene
SVA styrene vinyl acrylonitrile
TEO thermoplastic elastic olefin
TPE thermoplastic elastomer
TPE-O, TPO thermoplastic elastomer - olefinic
TPE-S thermoplastic elastomer - styrenic
TMC thick molding compound
TPU thermoplastic urethane
TVO thermoplastic vulcanites
UF urea formaldehyde
UHMWPE ultrahigh molecular weight polyethylene
ULDPE ultra low density polyethylene
UP,UPE unsaturated polyester (thermoset)
VA vinyl acetate
VAE vinyl acetate ethylene
VLDPE very low density polyethylene
XPS expandable polystyrene