Injection Molding Purging — Precision Control
PEKUTHERM® mechanical purging compounds are engineered for injection molding environments where downtime, contamination, and material waste are not acceptable. From small presses to high-tonnage machines running high-temperature engineering resins, Unitemp provides formulation-specific solutions based on machine size and processing temperature — delivering consistent, carrier-free, non-melting mechanical purge performance trusted in continuous production use since 1985.
How to Select the Right Injection Molding Formulation
Product selection depends on three variables:
• Machine tonnage
• Processing temperature
• Resin type and contamination level
Below is a clear decision guide for injection molding applications.
Many injection molding facilities are transitioning away from traditional chemical purge materials toward mechanical purging compounds that physically remove contamination.
https://www.pekutherm.org/post/mechanical-vs-chemical-purging-compounds-2026
Machine Tonnage
Injection molding machine size directly influences purge volume, pressure dynamics, and material displacement efficiency. PEKUTHERM® formulations are calibrated by tonnage range to ensure optimal barrel fill, controlled compression, and effective mechanical scrub action — whether operating a small 60-ton press or a large 500-ton production system.
Processing Temperature
Processing temperature determines which formulation delivers maximum purge performance. From ultra-low temperature applications at 175°F to high-heat engineering resins at 752°F, PEKUTHERM® maintains elastic, non-melting mechanical consistency across broad thermal ranges without chemical activation or carrier breakdown.
Resin Type & Contamination Level
Different resins — ABS, PC, Nylon, PEI, PVC, glass-filled compounds, color concentrates — leave different residues. Carbon buildup, degraded polymer, gas entrapment, and color streaking require mechanical displacement rather than chemical reaction. PEKUTHERM® physically scours contamination from screws and barrels to restore clean flow paths quickly and predictably.
What Makes PEKUTHERM® Different?
Unlike chemical or resin-based purging products, PEKUTHERM®:
• Does not melt
• Transitions to an elastic, soft-scrub consistency
• Physically scours barrels, screws, and hot runners
• Removes color, carbon, degraded resin, and gas residues
• Works across high and low processing temperatures
This is mechanical purging — not chemical reaction.
Formulation Breakdown
PEKUTHERM® HLT
High-temperature formulation for demanding engineering resins. Designed for broad processing ranges and aggressive contamination removal.
Pekutherm “HLT” has a broad working temperature range it’s a “soft-scrub” physical action Purging Compound, that vigorously yet gently scours away outgoing plastic, built up previous material, burnt on residues, expels color and off spec contaminants including gas residues. Pekutherm “HLT” has no chemical reactant, hybrid lubricant, carrier resin, or abrasive additive. It is one hundred percent pure. Pekutherm “HLT” does not melt, upon use it reaches the “soft-scrub” consistency of “pencil eraser”, and this is what provides the elastic-like scrub action.
PEKUTHERM® HLT Fine
Same performance as HLT with smaller granulate size for high pressure systems.
Pekutherm “HLT – Fine” has a broad working temperature range it’s a “soft-scrub” physical action Purging Compound, that vigorously yet gently scours away outgoing plastic, built up previous material, burnt on residues, expels color and off spec contaminants including gas residues. Pekutherm “HLT – Fine” [smaller granulate size] has no chemical reactant, hybrid lubricant, carrier resin, or abrasive additive. It is one hundred percent pure. Pekutherm “HLT – Fine” does not melt, upon use it reaches the “soft-scrub” consistency of “pencil eraser”, and this is what provides the elastic-like scrub action.
PEKUTHERM® ULT
Ultra-low temperature formulation engineered for flexible resins and low-heat processing.
Pekutherm “ULT ” has a ultra low working temperature range it’s a “soft-scrub” physical action Purging Compound, that vigorously yet gently scours away outgoing plastic, built up previous material, burnt on residues, expels color and off spec contaminants including gas residues. Pekutherm “ULT” has no chemical reactant, hybrid lubricant, carrier resin, or abrasive additive. It is one hundred percent pure. Pekutherm “ULT” does not melt, upon use it reaches the “soft-scrub” consistency of “pencil eraser”, and this is what provides the elastic-like scrub action.
PEKUTHERM® ULT Fine
Fine granulate version of ULT for precision components and small gate geometries.
Pekutherm “ULT – Fine” has a ultra low working temperature range it’s a “soft-scrub” physical action Purging Compound, that vigorously yet gently scours away outgoing plastic, built up previous material, burnt on residues, expels color and off spec contaminants including gas residues. Pekutherm “ULT – Fine” [smaller granulate size] has no chemical reactant, hybrid lubricant, carrier resin, or abrasive additive. It is one hundred percent pure. Pekutherm “ULT – Fine” does not melt, upon use it reaches the “soft-scrub” consistency of “bubblegum”, and this is what provides the elastic-like scrub action.
PEKUTHERM® N
Optimized for large injection molding machines operating in mid-temperature ranges.
Pekutherm “N” is a “soft-scrub” physical action Purging Compound, that stridently yet gently scours away outgoing plastic, built up previous material, burnt on residues, expels color and off spec.contaminants including gas residues. Pekutherm “N’ has no chemical reactant, hybrid lubricant, carrier resin, or abrasive additive. It is one hundred percent pure. Pekutherm “N” does not melt, upon use is reaches the “soft-scrub” consistency of a common pencil eraser, and this is what provides the elastic-like scrub action.
PEKUTHERM® SM
Designed for mid-size presses with balanced purge performance.
Pekutherm “SM” is a “soft-scrub” physical action Purging Compound, that stridently yet gently scours away outgoing plastic, built up previous material, burnt on residues, expels color and off spec.contaminants including gas residues. Pekutherm “SM” has no chemical reactant, hybrid lubricant, carrier resin, or abrasive additive. It is one hundred percent pure. Pekutherm “SM” does not melt, upon use is reaches the “soft-scrub” consistency of a common pencil eraser, and this is what provides the elastic-like scrub action.
PEKUTHERM® SK
Engineered for small injection molding machines where barrel clearance is limited.
Pekutherm “SK” is a “soft-scrub” physical action Purging Compound, that stridently yet gently scours away outgoing plastic, built up previous material, burnt on residues, expels color and off spec.contaminants including gas residues. Pekutherm “SK” has no chemical reactant, hybrid lubricant, carrier resin, or abrasive additive. It is one hundred percent pure. Pekutherm “SK” does not melt, upon use is reaches the “soft-scrub” consistency of a common pencil eraser, and this is what provides the elastic-like scrub action.
Learn About Plastic Purging Compounds
PEKUTHERM® mechanical purging compounds are used by plastics processors worldwide to clean injection molding machines and extrusion equipment. Our technical guides explain how purging compounds work, when to use them, and how operators can reduce downtime during color or material changeovers.
Explore our latest guides:
What Are Purging Compounds? A Complete Guide for Plastics Processors (2026)
Mechanical vs Chemical Purging Compounds: What Plastics Processors Need to Know
https://www.pekutherm.org/post/mechanical-vs-chemical-purging-compounds-2026
How to Purge an Extruder (2026 Guide)
https://www.pekutherm.org/post/how-to-purge-an-extruder-2026
How to Purge an Injection Molding Machine (2026 Guide)
https://www.pekutherm.org/post/purge-injection-molding-machine-2026
Carbon Buildup in Plastic Processing Equipment: Causes and Cleaning Methods
https://www.pekutherm.org/post/carbon-buildup-extruder-cleaning-2026
PEKUTHERM® ULT: Ultra-Low Temperature Purging for Injection Molding
https://www.pekutherm.org/post/pekutherm-ult-ultra-low-temperature-purging-injection-molding