Guidelines for Injection Molded Thermoplastic … 3 Recommended Injection Molding Conditions General principles • The viscosity of some thermoplastic elastomers is more sensitive

Processing TPEsGuidelines for Injection Molded Thermoplastic Elastomers

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Recommended Injection Molding Equipment

Machine Type and CapacityTPE resins are best processed on reciprocating screw-type injection molding machines. These types of machines typically produce a more uniform melt temperature and homogeneous material. They also permit processing at lower temperatures.

When using injection molding machines with reciprocating screws, it is important to utilize 40-80% of the barrel capacity with a maximumresidence time of four to five minutes. In addition,note that the material can degrade when the shotweight is too small, which creates excessiveheat in the melt.

Clamp • 2.5-4.0 tons/in2 of projected shot area,including gates, runners, etc.

Screw• Standard polyolefin type• L:D ratio 20:1• Compression ratio minimum - 2.5:1

Barrel• Shot weight should utilize 40-80% of the barrel capacity• Maximum residence time of 5 minutes

Best Practices for Processing with Injection Molded TPEs RTP Company’s thermoplastic elastomer portfolio was designed to meet our customer’s most demanding applications and provide the highest value in the market. Due to their unique chemistry and broad performance characteristics, thermoplastic elastomers (TPEs) are an excellent choice for applications requiring elasticity, bondability, soft-touch and sealing properties. RTP Company’s TPE Compounds combine the performance characteristics of widely used thermoset rubbers, with the ease of thermoplastic processing.

This guide is designed to assist you in the proper processing equipment and conditions for thermoplastic elastomers to ensure maximum performance results for your application.

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Recommended Injection Molding Conditions General principles• The viscosity of some thermoplastic elastomers is more sensitive to shear than to heat. Contact your local Sales Engineer for further clarification • Optimum moldings are usually obtained with a relatively high injection speed• The material melt temperature has influence on cycle time, surface appearance and weldline strength

Drying ConditionsMost thermoplastic elastomers should be injection molded with a moisture content of less than .05%. TPEs can pick up some moisture during storage, especially when packaged in gaylords.

Recommended drying conditions for RTP Company TPE product series can be found below under molding conditions.

Storage ConditionsPlease reference your Material Safety Data Sheet prior to first-time handling.

TPE materials can be stored in a cool, dry environment for up to 2 years if maintained in their original packaging, and are sealed well against heat, moisture, and other contaminants.

To avoid potential processing problems during molding, moisture absorption must beminimized as much as possible. The following are recommended:

• Open bag or gaylord box at time of use• Partially used bag or box must be closed as soon as possible• Bring cold granules to ambient temperature while bag is closed

Molding Conditions

RTP 2700 Series (TPE-S)

Typical Molding Conditions English Standard SI Metric

TemperaturesRear zone 340 - 360 °F 171 - 182 °C

Center zone 350 - 370 °F 177 - 188 °C

Front zone 370 - 390 °F 188 - 199 °C

Melt 360 - 450 °F 182 - 232 °C

Mold 60 - 100 °F 16 - 38 °C

PressuresInjection 10000 - 15000 psi 69 - 103 MPa

Hold 5000 - 10000 psi 34 - 69 MPa

Back 50 - 100 psi 0.34 - 0.64 MPa

SpeedsFill 0.5 - 1 in/sec 13 - 25 mm/sec

Screw 60 - 90 rpm 60 - 90 rpm

DryingTime\Temperature 2 Hrs @ 175 °F 2 Hrs @ 79 °C

Dew Point n/a °F n/a °C

Moisture Content 0.05 % 0.05 %

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Molding Conditions, cont.

Please contact your local RTP Company Sales Engineer for more information, or visit www.rtpcompany.comand click the “People Finder” button to find your local Sales Engineer.

Permaprene™ 2800 Series (TPV Alloy)



Center zone 350 - 370 °F 177 - 188 °C

Front zone 370 - 390 °F 188 - 199 °C

Melt 360 - 450 °F 182 - 232 °C

Mold 60 - 150 °F 16 - 66 °C


Hold 5000 - 12000 psi 34 - 83 MPa

Back 50 - 100 psi 0.34 - 0.69 MPa


Screw 60 - 90 rpm 60 - 90 rpm

DryingTime\Temperature 2 Hrs @ 175 °F 2 Hrs @ 79 °C

Dew Point 0.0 °F -18 °C




Center zone 370 - 440 °F 188 - 227 °C

Front zone 380 - 450 °F 193 - 232 °C

Melt 380 - 460 °F 193 - 238 °C

Mold 70 - 120 °F 21 - 49 °C


Hold 5000 - 10000 psi 34 - 69 MPa

Back 50 - 100 psi 0.34 - 0.69 MPa


Screw 60 - 90 rpm 60 - 90 rpm

DryingTime\Temperature 2 - 4 Hrs @ 180 °F 2 - 4 Hrs @ 82 °C



Polabond™ 6003 Series (Specialty)

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Center zone 350 - 400 °F 177 - 204 °C

Front zone 360 - 430 °F 182 - 221 °C

Melt 360 - 450 °F 182 - 232 °C

Mold 60 - 90 °F 16 - 32 °C


Hold 5000 - 10000 psi 34 - 69 MPa

Back 50 - 100 psi 0.34 - 0.69 MPa


Screw 60 - 90 rpm 60 - 90 rpm

DryingTime\Temperature 2 - 4 Hrs @ 180 °F 2 - 4 Hrs @ 82 °C





Center zone 380 - 440 °F 193 - 227 °C

Front zone 400 - 480 °F 204 - 249 °C

Melt 410 - 485 °F 210 - 252 °C

Mold 75 - 125 °F 24 - 52 °C


Hold 5000 - 12000 psi 34 - 83 MPa

Back 50 - 100 psi 0.34 - 0.69 MPa


Screw 60 - 90 rpm 60 - 90 rpm

DryingTime\Temperature 2 - 4 Hrs @ 160°F 2 - 4 Hrs @ 71 °C

Dew Point n/a °F n/a °C



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Nylabond™ 6091 Series (Specialty)



Center zone 450 - 490 °F 232 - 254 °C

Front zone 460 - 500 °F 238 - 260 °C

Melt 505 - 540 °F 263 - 282 °C

Mold 90 - 160 °F 32 - 71 °C


Hold 5000 - 12000 psi 34 - 83 MPa

Back 50 - 200 psi 0.34 – 1.4 MPa

SpeedsFill 0.5 - 3 in/sec 13 – 76 mm/sec

Screw 50 - 200 rpm 50 - 200 rpm

DryingTime\Temperature 4 Hrs @ 180°F 4 Hrs @ 82 °C





Center zone 470 - 500 °F 243 - 260 °C

Front zone 490 - 520 °F 254 - 271 °C

Melt 500 - 530 °F 260 - 277 °C

Mold 90 - 130 °F 32 - 54 °C


Hold 5000 - 10000 psi 34 - 83 MPa

Back 50 - 100 psi 0.34 – 0.69 MPa

SpeedsFill 0.5 - 2 in/sec 13 – 51 mm/sec

Screw 50 - 200 rpm 50 - 200 rpm

DryingTime\Temperature 2 - 4 Hrs @ 175°F 2 - 4 Hrs @ 79 °C



Nylabond™ 6092 Series (Specialty)

Molding Conditions, cont.

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Two-Shot and Overmolding ConsiderationsTo ensure good bonding in most overmolded applications, the mold wall thickness should range between 0.028” (0.711 mm) and 0.150” (3.81 mm). For thin-walled sections, the use of mechanical interlocks is recommended to prevent the walls from being blown off the cores during the air-assist ejection process. For thick-walled sections, coring out the wall can minimize potential shrinkage issues and reduce the part weight and cycle time. Regardless of wall thickness, it is essential that the wall thickness of the substrate and the overmold are as uniform as possible (with variations no larger than 4:1) to obtain cycle times.

To achieve optimal bond strength in transfer molding or overmolding applications, it is advisable to pre-heat the rigid substrate to facilitate chemical adhesion.

For a list of bondable materials, visit:www.rtpcompany.com/elastomer

Support and ServicesRTP Company’s TPE Division has a singular focus on delivering customer value through our core commitments: Solutions, Customization, and Service. Our engineers are passionate about finding solutions that fit your application requirements and budget. Our history and expertise gives us some of the strongest custom compounding capability in the industry. And we are big enough to compete with anyone, anywhere, without sacrificing the individual attention to service that is critical to launching successful programs.

ContactsPlease contact your local RTP Company Sales Engineer for more information, or visit www.rtpcompany.com and click the “People Finder” button to find your local Sales Engineer.

ShrinkageShrinkage of TPEs is dependent on a number of variables, from processing conditions to part and mold design. Please contact your local RTP Company Sales Engineer or Technical Support person for guidance.

RTP CoMPany is committed to providing you with solutions, customization, and service for all of your thermoplastic needs. We offer a wide range of technologies available in pellet, sheet, and film that are designed to meet even your most challenging application requirements.

Please contact your local RTP Company Sales Engineer by calling 1-507-454-6900 1-800-433-4787 (U.S. only), E-mail [email protected] or visit www.rtpcompany.com

ColoRColor inspires, energizes, and builds brand recognition, and choosing the right supplier is as important as selecting the right color. We offer color technology options in standard precolored resins or custom compounds, UniColor® Masterbatches, or cube blends.

ConduCTIvEWe offer compounds for electrostatic discharge (ESD) protection, EMI shielding, or PermaStat® permanent anti-static protection. Available in particulate and all polymeric-based materials, these compounds can be colored, as well.

FlaME RETaRdanTWhether you are developing a new product or need to reformulate due to ever-changing regulations, we can custom engineer a flame retardant material with the exact properties you require.

STRuCTuRalOur reinforced structural compounds can increase strength, stiffness, and provide resistance to impact, creep and fatigue. Ideal for metal or other material replacement, our formulas can be customized to meet cost and performance targets.

TPEOur thermoplastic elastomers provide rubber-like performance with the processing benefits of thermoplastic resin. We offer a wide range of options, from standard, in-stock resins to custom compounds designed to meet your specifications.

WEaR RESISTanTOur wear resistant thermoplastic compounds can incorporate internal lubricants to reduce wear and friction, thereby lengthening the service life of your application and reducing your processing costs.

No information supplied by RTP Company constitutes a warranty regarding product performance or use. Any information regarding performance or use is only offered as suggestion for investigation for use, based upon RTP Company or other customer experience.

RTP Company makes no warranties, expressed or implied, concerning the suitability or fitness of any of its products for any particular purpose. It is the responsibility of the customer to determine that the product is safe, lawful and technically suitable for the intended use. The disclosure of information herein is not a license to operate under, or a recommendation to infringe any patents.

Copyright 2017 RTP Company, 10/17

RTP Company Corporate Headquarters • 580 East Front Street • Winona, Minnesota 55987 USA website: www.rtpcompany.com • email: [email protected]

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Guidelines for Injection Molded Thermoplastic … 3 Recommended Injection Molding Conditions General principles • The viscosity of some thermoplastic elastomers is more sensitive