Do you know common sense of plastics commonly used in PP and PE?

Do you know common sense of plastics commonly used in PP and PE?
PP polypropylene

Often referred to as wrinkled glue

Abbreviations: PP, PPR, PPN, PP-N, PP-K, PP-Ts, PP-NO, PP-SO.

1. The heat rejection temperature is 100℃, which can withstand water boiling, steam and disinfection.

2. Melts at about 170°C after being heated by a flame. The flame glows faintly, yellowish-blue. Still burning after coming out of fire. Smells like candles. Does not require cleaning. with other materials when it is turned off.

3. Shrinkage: Polypropylene is a semi-crystalline thermal material with a shrinkage rate of 1.8-2.5%, shrinkage of 8.5% in 24 hours and 98% in first week, and it is fully cured in boiling water for 1 hour. Note: If shrinkage time is too long, it means that an error occurred during injection molding process (such as high mold temperature, glue temperature too low, and pressure too high). If there is no excessive deformation in boiling water for 15 minutes, it means that there is no problem in injection molding process.

4. The addition of 30% glass fiber (named PPGF30) can reduce shrinkage by up to 0.7%.

5. It must not be exposed to light outdoors. It will dissolve with aromatic or chlorinated carbon at a high temperature of 85°C. Contact with copper-containing mixed plastics at high temperatures will cause decomposition.

6. PP is a semi-crystalline thermal material, mold temperature is 50°C, universal screws (L:D=20:1) can be used.

7. Adhesive temperature: 220~275°C, do not exceed 275°C, otherwise viscosity will change abruptly and oxidation will occur.

8. Preservation of cylinder material: time at 260°C should not exceed 5~6 minutes, and time at 270°C should not exceed 2~3 minutes.

9. Temperature setting value:

After 190~230℃

Medium200~240℃

Medium210~260℃

Up to220℃~270℃

Gee220~270℃

Mould30~80℃

10. Injection speed: high speed (can reduce internal stress and deformation), if there are lines on surface of mold, if there are problems with surface, low speed and high mold temperature, and high pressure can be used. be used.

11. Auger speed: according to cycle, lower back pressure, better.

Do you know common sense of plastics commonly used in PP and PE?
High density polyethylene HDPE

1. HDPE is a semi-crystalline thermoplastic with a shrinkage rate of 2.0% to 5.0% or even 5%. The mold temperature has a great influence on shrinkage rate, and mold temperature must be stable.

2. The temperature of mold should be 20°C. At this temperature, water absorption of product should be 0.01% for 24 hours. If necessary, bake at 65°C/3 hours. Use original beer plastic to dry for 2 hours and bake for 3 hours when adding bait material or when weather is humid from February to May.

3. Universal screws (L:D=20:1) can be used.

4. Maintaining pressure for a long time can ensure stability of product.

5. When heated, it burns easily, flame is blue and yellow, only a little smoke, there are drops of burning glue, after extinguishing it emits a waxy smell.

6. Applicable temperature: 220~260°C. If temperature is 270°C, stop time of cylinder should not exceed 5~6 minutes, and if temperature is 280°C, it should not exceed 2~3 minutes. .

7. Temperature setting:

After160~200℃

Medium170~230℃

Medium200~260℃

Up to 220~280℃

Gee210~270℃

Mould10~60℃

8. Injection speed: High speed injection or multi-stage injection can be used.

9. Auger speed matching cycle:

The lower back pressure, better.

Do you know common sense of plastics commonly used in PP and PE?
low density polyethylene LDPE

1. Large shrinkage: 1.5–5.0%.

2. It burns easily when heated, flame is blue and yellow, there is little smoke, drops of burning glue, after extinguishing a waxy smell comes out.

3. The optimum mold temperature is 30°C. After 24 hours at room temperature, water absorption is 0.02%. If necessary, you can bake at 65°C/3 hours. The glue temperature is from 180 to 280°C. Use original beer plastic to dry for 2 hours and bake for 3 hours when adding bait materials or in humid weather from February to May.

4. Universal screws (L:D=20:1) can be used.

5.Material turn-off time: at 270°C, holding time of material should not exceed 5-6 minutes, and at 285°C should not exceed 2-3 minutes.

6. Temperature setting:

After 120~200℃

Medium160~230℃

Medium180~260℃

Up to 200~280℃

Gee210~270℃

Mould10~60℃

7. You can use high speed injection or multi-stage injection.

8. Auger Speed ​​Matching Cycle: The lower back pressure, better.

Do you know common sense of plastics commonly used in PP and PE?

Recommended reading

1. "Heavy! BASF announces product price increase! Off-season is coming to an end! The futures side is pushing prices up and this increase is expected to continue"

2. "A simple method for identifying commonly used plastics"

3. “Oil overflows ports! 80 oil tankers roam off coast of China! Full lift! PP rose by 150 in a day, futures rose sharply"

4. “Plastic man must see! Comparison table of melting index of plastic grades! "