UNITIKA UNITIKA PLASTICS DIVISION
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Nylon Resin U-polymer TERRAMAC Unilate Elitel
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U-100 (neat polymer)
P Series
U Series
AX Series
Precautions in molding

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U-polymer > Precautions in molding Top Page
[UNITIKA U-polymer]

Precautions in molding

Injection molding and drying conditions for U polymers,
and precautions in molding
Print Table on A4 Paper
Brand
Cylinder temperature (°C)
Limit
temperature
(°C)
Mold temperature
(°C)
(actual surface
temperature)
Back pressure
(kgf/cm2)
(gage pressure)
Drying
temperature
(°C)
Drying
period
(hr)
Nozzle
Front
Middle
Rear
U-100
350~
370
350~
370
340~
360
310~
330
390
120~140
5~15
140
6~24
UG-100-20
350~
370
350~
370
340~
360
310~
330
390
120~140
5~15
140
6~24
UG-100-30
350~
370
350~
370
340~
360
310~
330
390
120~140
5~15
140
6~24
P-1001
350~
370
350~
370
330~
350
310~
330
390
120~140
5~15
140
6~24
P-3001
330~
350
330~
350
320~
340
290~
310
370
110~130
5~15
140
6~24
P-5001
310~
330
310~
330
300~
320
270~
290
350
100~120
5~15
140
6~24
P-1001A
350~
370
350~
370
330~
350
310~
330
390
120~140
5~15
140
6~24
P-3001S
330~
350
330~
350
320~
340
300~
320
380
100~120
5~15
140
6~24
L-1003PA
350~
370
350~
370
330~
350
310~
330
390
120~140
5~15
140
6~24
PT-3020
330~
350
330~
350
320~
340
290~
310
370
110~130
5~15
140
6~24
C300VN
300~
320
300~
320
280~
300
260~
280
330
100~120
5~15
130
6~24
U-8000
270~
290
270~
290
260~
280
250~
270
300
70~90
5~15
110
10~24
U-8400H
250~
270
250~
270
240~
260
230~
250
290
50~70
5~15
100
10~24
L-8005
270~
290
270~
290
260~
280
250~
270
300
70~90
5~15
110
10~24
LM-8503-10
250~
270
250~
270
240~
260
230~
250
290
70~90
5~15
100
10~24
FUN-8000
280~
300
280~
300
270~
290
260~
280
310
70~90
5~15
120
8~24
UM-8400-20
250~
270
250~
270
240~
260
230~
250
290
70~90
5~15
100
10~24
UM-8430RG
250~
270
250~
270
240~
260
230~
250
290
70~90
5~15
100
10~24
AX-1500
250~
270
250~
270
240~
260
210~
230
290
70~90
5~15
100
10~24
AXG-1500-30
250~
270
250~
270
240~
260
210~
230
290
80~120
5~15
100
10~24
AXF-1500-05
250~
270
250~
270
240~
260
210~
230
290
70~90
5~15
100
10~24
AX-1500W
230~
250
230~
250
220~
240
200~
220
290
40~60
5~15
100
10~24

* If the cylinder temperature indicated above is not high enough to provide the material with desirable flowability, the temperature may be raised up to the limit temperature to improve flowability.
* Proper setting of the screw back pressure is effective for improving blending efficiency and for removal of gases, and thus make sure to set a suitable back pressure.
* If a hot-air-circulating tray drier is used, place and dry the pellet in a layer with a thickness of 3 cm or less under the condition above.
* Use of a dehumidifier, reduced-pressure or vacuum type drier allows more efficient drying.
* The water content of the resins other than the AX series should be less than 200 ppm, and those of the AX series, less than 2000 ppm.
* Make sure to heat the hopper immediately above molding machine, for example, by employing a hopper drier, for the purpose of raising the temperature of the pellets therein to the drying temperature and preventing them from absorbing moisture.
* As the resins are ester resins, presence of excessive water leads to hydrolysis of the resins during heat processing, decrease in the molecular weight of the resins, and consequently decrease in the quality of molded products. Comply strictly with the drying condition indicated above, and take notice of reabsorption of water during molding.
* Lower mold temperature may result in residual strains at the sharp edge and gate portions of the molded products, which may results in cracks. Make sure to raise the mold temperature (mold surface temperature actually determined) into the range of temperature indicated above as standard.
* Select a suitable molding machine so that the amount of resin injected per shot is equivalent to 30 to 70% of its cylinder capacity.
* If a resin remains in the molding machine for 10 minutes or more, remove the resin thoroughly form the molding machine and then restart molding. If not, products in poor appearance such as burns and silver may result.
* Note that antirusts and other oils remaining adherent to the mold may cause cracks in the products.
* If there remains hazes on the surface of molded products of AX series resins, raise the temperature of mold and cylinder and make sure to remove gases in the mold thoroughly.


Extrusion molding of U polymers
See the table above for the settings of barrel temperature and the conditions of drying resins.
Contact our sales department for details.

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