How to Choose the Right Plastic Purging Compound
Easypurge combines liquid, concentrated pellet and ready-to-use purging technologies to solve different cleaning challenges in plastics processing
1. What is a purging compound?
A plastic purging compound is a specialised cleaning material used by plastics processors to remove colour residues, degraded polymer, carbonised deposits and contamination from injection moulding machines, extruders, blow moulding machines, screws, barrels, nozzles, hot runners and dies.
It is used for colour changes, material changes, shutdowns, startups and preventive maintenance. Unlike purging with virgin resin or regrind, a purging compound is designed to clean faster, reduce scrap and minimise production downtime.
In simple terms, water may clean your hands, but soap makes the process faster and more effective. The same applies to plastics processing machines.
Different purging issues require different technologies: low-dosage liquid purges for routine changes, and stronger cleaning action for black specks, carbonised deposits, hot runners or difficult colour changes.
2. What types of purging technologies are available?
Easypurge combines liquid, concentrated pellet and ready-to-use purging technologies to solve different cleaning challenges in plastics processing.
APC Liquid
Low-dosage liquid purging technology designed for fast colour changes, hot runners, PET preform applications and reduced purge consumption.
Recognised as a leading purging solution for EBM applications.
CT Concentrated Pellets
Concentrated pellet technology developed for difficult colour changes, black specks, carbon deposits and demanding contamination problems.
RU Ready-to-Use Pellets
Ready-to-use purge designed for operational simplicity and highly recommended for polyolefin extrusion applications.
3. Can liquid purge and concentrated pellets work together?
In highly demanding purging situations, APC Liquid and CT concentrated pellets can be combined to achieve a stronger synergistic cleaning effect.
This approach is especially useful for difficult colour changes, persistent black specks, hot runners, extrusion heads with complex geometries and carbonised residues, helping improve cleaning efficiency and reduce downtime.
Technical recommendation: combination purging should be evaluated according to resin, temperature, machine type and contamination level.
4. Why use a plastic purging compound?
Using a plastic purging compound helps processors reduce scrap, shorten machine downtime, remove contamination and optimise the total cost per purge in injection moulding, extrusion, blow moulding and hot runner applications.
Key Benefits
• Reduced scrap during colour changes
• Less machine downtime
• Black specks and contamination removal
• Reduced screw pulls
• Improved hot runner cleaning
• Lower rejection rates
• Optimised cost per purge
5. How do you choose the right purging technology?
The right Easypurge technology depends on the production problem, polymer type, machine process, temperature and contamination level.
APC Liquid
Small and medium-size injection moulding machines, frequent colour changes, hot runner cleaning, PET preform colour changes and startup purging. Recognised as a leading solution for EBM and PET preform production, accepted by major brands in the sector.
CT 101
Polyolefin applications and all injection moulding machine sizes, especially large machines where reducing colour change downtime and minimising scrap are key priorities. Especially cost-effective for efficient machine cleaning in high-volume production environments.
CT 301
Transitions from polyolefins to PA, ABS and styrenic materials, especially when changing between polymer families with different polarity. Also highly effective for difficult colour changes within the same material.
CT 401
Transparent materials such as PC and PMMA, where clean colour transitions and residue-free purging are critical.
RU Pellets
When simple operation, no pre-blending and polyolefin extrusion are required.
APC + CT
Combine both in extremely demanding cases: persistent black specks, difficult colour changes, hot runners and extrusion heads with complex geometries, where a stronger synergistic cleaning effect is required.
6. What problems can plastic purging compounds solve?
Purging compounds are commonly used to prevent or remove contamination and processing issues such as:
• Black specks caused by carbonised material
• Colour streaks from previous pigments
• Gels and unmelted resin
• Degraded polymer residues
• Material trapped in dead zones
• Contamination after shutdowns
• Difficult transitions between incompatible materials
• Colour residues in hot runners
• Carbonisation in screws, barrels, nozzles or dies
7. Why is purging with resin alone not always enough?
Virgin resin is designed to be processed into parts, films, profiles or containers. It is not designed to remove carbonised material, colour residues, gels or degraded polymer accumulated inside the machine.
During production, residues can remain trapped in low-flow areas such as:
• Screw flights
• Non-return valves
• Nozzles
• Hot runners
• Dies
• Barrel dead zones
• Mixing sections
Over time, these residues may degrade, burn or contaminate the next production run. This can lead to black specks, colour streaks, gels, rejected parts and unnecessary machine stops.
A plastic purging compound helps remove these residues more efficiently, reducing contamination, scrap and downtime.
8. How should you calculate the real cost per Purge?
Don’t compare price per kg.
Compare cost per purge.
When comparing purging compounds, the cheapest product per kilogram is not always the most cost-effective solution.
A low-cost purge may require more material, more flush resin, longer machine downtime and more rejected parts before production returns to acceptable quality. In contrast, a concentrated or more efficient plastic purging compound can reduce total material consumption, shorten changeover time and bring the machine back to production faster.
TOTAL PURGING COST =
Purging material + Flush resin + Machine downtime + Labour + Scrap + Lost production
This gives processors a more accurate view of the economic impact of each colour change, material change or maintenance purge.
Frequently asked
QUESTIONS
What is the best purging compound for injection molding?
The right purge depends on the resin, contamination and machine. EASYPURGE APC sachets and CT pellets target color, black specks and degraded resin, but the best choice depends on your process. See how to choose below ...
EASYPURGE APC liquid sachets are especially practical for regular purging, preventive cleaning and difficult color changes in medium-size injection molding machines.
They are easy to dose and help clean screws, barrels, nozzles and hot runner systems.
Easypurge CT pellets can be used in any machine size and process. They are mixed with the next material, virgin material, regrind or transition resin at 30–50%. CT101 is ideal for difficult changes and black specks in polyolefins. CT301 is designed for transitions, colors and black specks. CT401 is recommended for transparent parts, colors and haze.
How do you reduce color change downtime in injection molding?
Color change downtime drops when pigment is removed from the areas where it hides, not just pushed through the barrel. EASYPURGE APC and CT pellets help clean screws, valves, nozzles and hot runners. See how it works. Below...
Color streaks usually appear when pigment deposits or degraded resin are released from low-flow areas during the next production run. These areas can include the screw, barrel, check valve, nozzle, hot runner manifold, tips and dead zones.
For injection molding machines between 100T and 1000T, EASYPURGE APC liquid sachets are a clean and accurate option for fast color changes. For processors who prefer pellets, the CT line improves flow, wettability and mechanical cleaning efficiency. CT301 is the most versatile choice for transitions, color changes and black specks.
Can purging compounds remove black specks, gels and carbon contamination?
Yes. Black specks, gels and carbon often come from degraded resin trapped in low-flow areas. EASYPURGE APC and CT pellets help remove contamination before it reaches production. See which option fits your line best, below...
Black specks can appear randomly because small amounts of degraded material break loose from the screw, barrel, nozzle, hot runner or extrusion head. Once this contamination enters production, it creates scrap, downtime and quality problems.
EASYPURGE APC liquid sachets are useful for preventive cleaning and for removing black specks in medium-size injection molding machines. In pellet format, CT101 is the best fit for difficult changes and black specks in polyolefins. CT301 is recommended when the application involves transitions, colors, black specks or a wider range of materials.
Are purge compounds safe for hot runners?
Yes, when the purge is selected correctly. Hot runners need controlled cleaning because pigments and degraded resin can hide in manifolds, tips and channels. EASYPURGE offers liquid and pellet options. Learn how below...
Hot runners require a purge that cleans effectively without relying on aggressive or abrasive action.
EASYPURGE is designed for demanding injection molding applications where residues can remain in areas that are difficult to clean with virgin resin alone.
For standard injection molding machines between 100T and 1000T, APC liquid sachets offer simple and precise dosing. CT pellets can be mixed at 30–50% with the next material, virgin resin, regrind or transition material, helping create a cleaner start-up after purging.
Liquid vs pellet purging compound: which one should I choose?
Liquid or pellet depends on the process, dosing preference and cleaning challenge. APC sachets simplify accurate dosing, APC bottles suit EBM, and CT pellets work broadly at 30–50%. See which format fits your line best, below…
EASYPURGE APC liquid sachets are especially practical for regular purging, preventive cleaning and difficult color changes in medium-size injection molding machines.
They are easy to dose and help clean screws, barrels, nozzles and hot runner systems.
Easypurge CT pellets can be used in any machine size and process. They are mixed with the next material, virgin material, regrind or transition resin at 30–50%. CT101 is ideal for difficult changes and black specks in polyolefins. CT301 is designed for transitions, colors and black specks. CT401 is recommended for transparent parts, colors and haze.
How much purging compound should I use?
The right amount depends on screw capacity, resin, machine size and contamination level. APC liquid and CT pellets use different dosing methods, so the best purge quantity depends on your setup. See the full guide now. Below...
For EASYPURGE APC liquid sachets, dosing is especially practical when the operator needs a clean, pre-measured format for regular color changes, black specks or preventive cleaning in injection molding and extrusion.
For EBM — extrusion blow molding — the APC liquid bottle presentation is the ideal format because it is easier to dose into the process and works well for cleaning extrusion heads, flow channels and areas where material tends to stagnate.
For Easypurge CT pellets, the recommended use is 30–50% blended with the next material, virgin resin, regrind or transition material. CT pellets can be used across all processes and machine sizes.
Is EASYPURGE safe for machines and operators?
Yes. EASYPURGE is designed for plastic processing equipment and operators when used correctly. APC liquid avoids abrasive action and helps reduce issues linked to some chemical purges. See safety details below ...
Different purge products use different technologies, so safety depends on selecting the correct solution and following the safety data sheet. EASYPURGE APC was developed for use in plastic processing equipment and is especially useful when cleaning screws, barrels, nozzles, hot runners and areas where degraded material can accumulate.
Can EASYPURGE reduce scrap, downtime and purging costs?
Yes. EASYPURGE can reduce scrap, downtime and purge cost by cleaning faster and preventing residues from reaching the next run. The real savings come from less waste, less time and smarter dosing. See why below ....
EASYPURGE should be evaluated by the total cost of the purge, not only by the price per kilo. A purge that reduces machine downtime, scrap, start-up contamination and the amount of material required can generate a much lower real cost per changeover.
EASYPURGE APC liquid helps reduce cost because it is a concentrated liquid technology designed to deliver active cleaning performance without unnecessary carrier material.
Easypurge CT pellets also improve cost efficiency because they are concentrated and used at 30–50% mixed with virgin material, regrind or transition material. This allows processors to adapt the purge mix to the process, reduce the amount of purge product consumed and lower the cost per purging operation.
The CT range also improves flow, wettability and mechanical cleaning efficiency, helping reduce time, waste and scrap during transitions, difficult color changes and black speck removal.
Can I use a different polymer as a transition material for purging?
Yes. A different polymer can be used as a transition material when the production resin is costly or difficult. The key is choosing a compatible material and switching back correctly. See the safest procedure below now.
If the production material is expensive, a different polymer can be used as long as it has a similar or lower MFI and works in the same or a higher temperature range. Once the system is clean, the operator can switch back to the regular production material.
How do I purge when switching between polymers with different processing temperatures?
Use a bridge material when polymers have very different processing temperatures. Clean at the current temperature first, then adjust before introducing the next resin. This avoids gels and black specks. See how below...
The key point is to avoid exposing a sensitive resin to the wrong processing temperature. When moving from a lower-temperature material to a higher-temperature material, use a bridge material such as HDPE, PP or PE when suitable for the resin family and temperature range. Clean the system at the temperature of the material currently in production, removing as much of the previous resin as possible before increasing the barrel temperature.
When moving from a higher-temperature material to a lower-temperature material, clean the system before lowering temperatures. This helps prevent remaining high-temperature resin from solidifying inside the barrel and creating gels, contamination or black specks during the next production run.
EASYPURGE APC liquid and Easypurge CT pellets can support this procedure depending on process and dosing preference. APC liquid sachets are practical for injection machines from 100T to 1000T and extrusion up to 80 mm; APC liquid bottle presentation is ideal for EBM; CT pellets can be blended at 30–50% with virgin, regrind or transition material.
Technology of EASYPURGE
EASYPURGE cleaning technology ensures fast, safe and efficient purging — for clean machines, less downtime and perfect production results.
HIGH TEMPERATURE RANGE
SAFE AND NON-TOXIC
COST EFFICIENT
NON-ABRASIVE
efficient cleaning
ALL-IN-ONE-solution
convenient
The smart solution against Black Specks.
Black specks are one of the most common and costly challenges in plastics processing — especially during color or material changes. They are caused by burned material, carbonized residues or contamination inside the machine — often in areas that are difficult to reach.
The EASYPURGE Black Speck Solution combines the mechanical cleaning power of a high-performance granulate with the chemical action of our liquid cleaner. This dual-action technology removes even the most stubborn contamination deep inside screws, barrels and hot runner systems.
During the cleaning process, the liquid develops a controlled chemical reaction that temporarily increases the Melt Flow Index (MFI). This ensures optimal contact time and cleaning performance — allowing the purging compound to penetrate into critical areas, dead spots and difficult geometries.
The system is completely food-safe and also perfectly suited for technical plastics and industries with the highest quality standards — such as automotive, packaging or medical applications.
- Dual-action cleaning: Mechanical granulate combined with chemical liquid
- Increases Melt Flow Index for maximum cleaning efficiency
- Removes black specks, color residues and degraded material
- No dismantling of machine parts required
- Safe for screws, barrels and hot runner systems
- FDA certified food-safe formulation
- Perfect for technical plastics in demanding industries
- Faster color and material changes — with zero black specks
EASYPURGE Liquid - Easiest way to purge
EASYPURGE Liquid is the ideal purging solution for fast and uncomplicated cleaning of injection and extrusion molding machines. It works purely through a chemical reaction — without any abrasive particles — making it safe for machines, hot runner systems and sensitive production environments.
The liquid is introduced into the machine together with the production material. During the purging process, it triggers a controlled chemical reaction that temporarily increases the Melt Flow Index (MFI) of the plastic. This allows residues, color pigments and degraded material to detach more easily from the screw, barrel and hot runner areas — and be completely purged out of the machine.
EASYPURGE Liquid is especially effective for color changes and material changes — even when switching between demanding plastics or sensitive applications. Thanks to this process, the purged material is not classified as hazardous waste. It can be collected and recycled by specialized recycling companies — making the process more sustainable. The liquid is fully food-contact approved and is particularly suitable for industries such as the packaging industry, medical technology.
The convenient single-use sachets make application even easier, ensuring precise dosing and clean handling — directly at the machine.
Key Benefits of EASYPURGE Liquid:
- Pure chemical cleaning — no abrasive particles
- Pure chemical cleaning — no abrasive particles
- Fast and easy application — perfect for small and medium sized machines
- Increases the Melt Flow Index for optimized cleaning performance
- Ideal for color changes and material changes
- No special waste — purged material can be recycled
- Safe for hot runner systems and sensitive equipment
- Complied with FDA regulations
- Easy dosing with convenient single-use sachets
- Clean and reliable results in just a few minutes
Black Speck Solution
Applications:
Screw Cleaning, Barrel Cleaning, Hot Runner Cleaning, Shutdown
Range of Application:
ABS, AMMA, EVA, EVOH / EVAL, PA, PBT, PC, PC-ABS, PE, PET, POM, PPE, PPO, PP, PS, PPS, PVDC, PVC, SAN, TPE
Process:
Injection Molding, Extrusion Molding, Blow Molding
Temperature:
190-300°C
Product Type:
Pellets and Liquid
FDA / GRAS:
Yes, approved
Liquid Purging Compound
Applications:
Screw Cleaning, Barrel Cleaning, Hot Runner Cleaning, Shutdown
Range of Application:
ABS, AMMA, EVA, EVOH / EVAL, PA, PBT, PC, PC-ABS, PE, PET, POM, PPE, PPO, PP, PS, PPS, PVDC, PVC, SAN, TPE
Process:
Injection Molding, Extrusion Molding, Blow Molding
Temperature:
135-350°C
Product Type:
Liquid
FDA / GRAS:
Yes, approved
other solutions
EINMALIG AUF DEM MARKT.
in pellets form
In addition to our liquid solutions, EASYPURGE also offers a selection of high-quality purging compounds for different temperature ranges and applications. Whether for standard cleaning or specific material requirements — our granulates provide reliable and safe cleaning for various processes. More information is available directly in our online shop.
SAFE & HARMLESS
EASYPURGE is completely food-safe and harmless to health. During the cleaning process, no harmful gases or vapors are released — making it safe for operators, machines and the environment. In addition, the purged material can be recycled by specialized companies — reducing waste and supporting a more sustainable production process. Learn more about our commitment to safety and sustainability on our dedicated page.
Change today!
Stop wastinG
time and material
With EASYPURGE you can optimize your production processes, reduce downtime and minimize material waste — while cleaning your machines faster and more efficiently than ever before.
And the best part: All of this with 100% safety. Food-safe. Operator-friendly. Machine-friendly.
Start saving today — with purging solutions that pay off from the very first use.
Best Solution for Preform Injection Molding
Automatic Purging System
The APS is an automated purging solution developed by EASYPURGE to ensure consistent, repeatable, and operator-independent cleaning results.
It allows the purging agent to be dosed directly into the machine at the optimal time and quantity — fully integrated into your process.
APS helps to standardize cleaning cycles and reduce human error, especially in high-volume or multi-machine environments.
- Fully automated dosing of purging agent
- Consistent cleaning quality across all shifts and operators
- Time-saving and ideal for multi-machine production lines
Why aps makes a differece
It ensures that the purging agent is applied at the right moment, in the right amount, and in exactly the same way — every time.
This leads to more predictable cleaning performance, better machine uptime, and optimized material usage.
Especially in high-volume production environments or facilities with multiple machines, APS helps reduce human error and improves overall process reliability.
Why EASYPURGE?
Clean faster, save material and achieve perfect results with EASYPURGE.
EASYPURGE Liquid cleans significantly faster than conventional purging compounds. Thanks to its chemical cleaning action, cleaning times can be reduced by up to 60%, while material waste is reduced by up to 50%. The purging process becomes quicker, easier and more efficient — without compromising on safety or cleaning performance.
For one of the biggest challenges in plastics processing — black specks — we have developed the Black Speck Solution. This innovative system was specifically designed to remove even the most stubborn contamination and burnt residues, ensuring perfect results during color and material changes — even in demanding production environments.
Test our products
— risk-free.
We want you to experience the performance of EASYPURGE in your own production. That’s why we offer product samples for all our solutions — so you can test them directly on your machines without any risk.
Simply contact us to request your free sample package.
To ensure the best results, we are also happy to support you with a free technical consultation — helping you choose the right product and ensuring a smooth and efficient cleaning process.
You got interested?
Our full range of purging solutions is available online – fast, direct, and hassle-free. Whether you’re looking for our innovative Black Speck Solution or our trusted liquid cleaner, you can easily find the right product, download datasheets, and place your order in just a few clicks.
No waiting. No detours. Just clean production – made simple.
