Purging Material for injection molding machine (Plastic purging agent)

Instruction Manual for Injection molding- complete - 1/5

Usage guideline
Refer to the following values for the amount of purge agent used.
Clamping Force (ton)

80

150

550

1000

Quantity of Celpurge

0.2〜0.6kg

0.3〜0.8kg

2〜6kg

4〜10kg・The required amount varies depending on the weighing position of the preceding material,
the degree of contamination of the cylinder and screw, and the type of the preceding material(difficulty of replacement).

・Cleaning the hot runner requires 1.2 to 1.5 times the above quantity.

General usage
Cleaning of Celpurge
Retract the injection unit and separate the nozzle from the mold.
Repeat the weighing / injection or increase the back pressure to completely
discharge the preceding material in the cylinder, then clean the hopper withsuction or compressed air.
Load Celpurge to the hopper, set the condition settings to the recommended
values in the table below, repeat weighing and injection, and replace thepreceding material with Celpurge.
Conditions for purging recommended settings
Weighing

Back pressure

Screw speed

Cylinder temperature(operating temperature)Injection speed

10〜30mm

0〜5MPa（※1）

50〜100rpm

No change（※3）

30mm/sec more

*１ Depending on the temperature range used, the Celpurge may drop from the tip of the nozzle during measurement
and the measurement may stop. In that case, reduce back pressure until weighing is possible. Also, dependingon the molding machine, if the back pressure is set to zero completely, air will enter from the nozzle tip, making it
impossible to measure the purge agent.

*2 If the back pressure is adjusted with (*1) and the weighing does not work, increasethe number of rotations until the back pressure is low and weighing becomes possible.

*3 If the processing temperature during molding is within the recommended operating

temperature range for the Celpurge to be used, it is not necessary to change the temperature setting.
◆Notes for usage

・ Read SDS through before usage.

・ Do not blend with other materials.

・Use Celpurge within operational temp. range.

・Use under well-ventilated conditions.
・Purged materials can cause smoke or fire, do not leave around combustible materials.

・For your safety, use protective equipments ( gloves, goggles, etc.).

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Purging Material for injection molding machine (Plastic purging agent)

Instruction Manual for Injection molding- complete - 2/5

Operations after replacement[ When stopping the machine ]After replacing with Celpurge, weigh in manual mode and stop the machine.
◆Notes for usage
When the inside of the cylinder is empty, air enters from the nozzle tip,and carbonized foreign matter is likely to form due to the thermal oxidation deterioration of the resin.

[ At startup ]Turn on the heater power.
After raising the temperature and confirming that the temperature is stable,
discharge the purge agent remaining in the cylinder.
After cleaning the inside of the hopper with compressed air etc., replace withthe subsequent material and repeat the measurement and injection, or raise theback pressure and rotate the screw to replace the Celpurge with the subsequentmaterial and start molding.

[ When molding the following materials(no change in set temperature, no mold change) ]After replacing with Celpurge, repeat weighing and injection, or increase theback pressure to discharge the Celpurge remaining inside as much as possible.
After discharging the Celpurge, suction the inside of the hopper or clean it withcompressed air and add the next material.
[ When molding the following materials(change of set temperature, change of mold) ]After the replacement by Celpurge is completed, turn off the heater in themanual mode after weighing one shot. (Use Celpurge as a sealant)◆Notes・If the cylinder is empty, air will enter from the tip of the nozzle and thermal oxidation deterioration of the resin willeasily cause carbonized foreign matter.

・When keeping the measured state with the heater ON (sticker), perform it within the operating temperature rangeof Celpurge. Celpurge For the operating temperature range of each grade, refer to the values listed in our Celpurge
HP and catalogs.

・If it is unavoidable to stay above the upper limit of the operating temperature, be sure to stop it for ashort time, lower the nozzle temperature (180 to 200°C as a guide) so that air does not enter the cylinder.

Perform mold replacement work.
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Purging Material for injection molding machine (Plastic purging agent)

Instruction Manual for Injection molding- complete - 3/5

Turn on the heater and set the processing temperature of the material to be molded.
After discharging the Celpurge remaining in the molding machine and cleaning
the inside of the hopper with compressed air, etc., add the subsequent materials
into the hopper.Then, repeat weighing and injection, or apply back pressure torotate the screw to completely discharge the Celpurge remaining in the moldingmachine.
◆Note・ Make sure that the processing temperature of the post-molding material is higher than the lower limit
temperature of Celpurge. If the screw is rotated below the lower limit temperature of Celpurge, load will beapplied to the machine and it may cause malfunction.

Measures against Carbonized Material andManual for Elimination
Measures against Carbonized Material : Key Points
There are various factors that cause carbonized material in plastics processing machines, however,measures to prevent it can be summarized into the following 3 points.

Do not allow molding materials to remain in the cylinder or nozzle.
Clean the cylinder and screw regularly.
Prevent degradation of molding materials through oxidation.

Causes of Carbonization and Countermeasures

Here is a list of the factors and how they affect the yield of carbonized material.
Source of carbonization(molding materials )Carbonized material

Temp

Time

O2

[ Source of carbonization ( = molding materials ) ]Bromine, chlorine and other halides are often used as flame-retardants, and halides allowed to remain in
the cylinder can cause carbonization because they are very easily thermally degraded. Flame-retardants
are normally indicated on the SDS (material safety data sheet) as ingredients, and this should be checked inadvance.
However, all molding materials are carbon compounds and can be carbonized if left in the cylinder for along period. Thus, the most important measure against carbonized marerial is not to leave molten materials
in the cylinder.
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Purging Material for injection molding machine (Plastic purging agent)

Instruction Manual for Injection molding- complete - 4/5[ Temperature ]Temperature is a very important factor to avoid carbonization. The higher the temperature, the faster thedegradation, thus avoid leaving materials in the cylinder at high temperatures. However, if it is unavoidable,
replace the materials in the cylinder with a material that does not easily degrade.
* Celpurge, if used within operational temperature range, does not easily cause carbonized material, works
as a sealant and blocks off oxygen.

[ Time ]Molding materials (polymer itself or ingredients) get carbonized stepwise: the first stage is browning,
followed by gradual blackening, and finally adhering as completely carbonized buildup onto the surfaces ofthe screw, the cylinder, and the nozzle. Even if the same molding material is continuously being molded, alayer of carbonization will gradually form at stagnant areas, and, for example, in case of molding flame
retardant PP, completely carbonized material peels off of metal surfaces in two weeks and makes moldings
defective.
Once completely carbonized materials reach the ‘peeling away’ stage, they become impossible tocompletely eliminate with any purging compounds.
As a countermeasure to prevent buildup and adhering of carbonized materials, it is important to clean
regularly with purging compounds (Celpurge).

[ Oxygen ]Deterioration, decomposition, and carbonization of resins can occur even without oxygen, however, oxygen isa significant factor to accelerate carbonization. When changing molds, shutting down for the weekend, orwhen the temperature rises at the beginning of the week, if the screw is left empty, air can enter the cylinder
through the nozzle and develop carbonization. If you use Celpurge as a sealant, Celpurge will seal the nozzle
and block oxygen off, preventing carbonized material.
* Celpurge can effectively block the nozzle if the nozzle temperature is lowered to 180-200°C.

Molten resin

Resin burn andgel generation

Carbonizedlayer formationscrew/barrel
Unknowingly
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Purging Material for injection molding machine (Plastic purging agent)

Instruction Manual for Injection molding- complete - 5/5

Procedure for Elimination of Carbonized Material(in case of weekend shutdown and restarting at the beginning of the week)
Retract the injection unit.
Completely discharge any residual materials from inside the cylinder, clean
the hopper with suction or compressed air,
Add NX-VG2 and perform a cleaning.
* This is basically the same cleaning procedure written in [1]Add NX-VN2 and perform a cleaning procedure written in [1].
A good weight ratio of AG4 to MA2 is between 1/1 and 1/2.
After visually confirming the removal of Carbon Contamination, carry out theoperation after purging agent replacement according to the purpose as
described on page 2.
◆Note・Do not blend NX-VG2 and NX-VN2 prior to cleaning.

・When molding a polyolefin material, we recommend using NX-VC2 or P2S instead of VN2.
Operating temperature at below 250°C cannot use NX-VG3.

・The usage ratio with VG2 is the same as 04.

About sealants
If the remaining resin is discharged after molding is completed, air will be mixed in from the nozzle tip.If thetemperature is kept high in this condition, carbides will form due to thermal oxidative deterioration.
Generally, it is possible to physically scrape out the carbides by using a purge agent containing inorganic
substances such as glass.Therefore, it is recommended to use a sealant after the molding work to minimize
the generation of carbides.
Celpurge can also be used as a sealant, so after cleaning with Celpurge, switch to manual and weigh one
shot (weighing the same value as when purging) and stop the machine.

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