[Science Stickers] Useful knowledge of common plastic materials! You can use it sooner or later

1. PVC (UPVC, RPVC, PVC-U)

1. The best mold temperature is 40℃. The shrinkage rate of coarse powder is 0.1~0.5%, and the shrinkage rate of fine powder is 1.5%.
2. After 24 hours at room temperature, absorb 0.02% of water. If necessary, bake at 65℃/3 hours, and the glue temperature is between 180~205℃. Dry the raw material beer for 2 hours, and bake it for 3 hours when the sprue is added or the weather is humid from February to May.
3. It will burn if heated by fire, the flame is yellowish with light green, and a lot of thick smoke is emitted. Heating the flame on the copper wire will be green. After the machine is shut down, it must be cleaned with mild lye (such as sodium nitrate) and then sprayed with anti-rust oil, and the barrel shall be cleaned with PMMA, PP, LDPE, EPPS.
4. The glue temperature is 185-205℃, 200℃ can not stay for 5 minutes, and 210℃ can not stay for 3 minutes.
5. Temperature setting: rear: 140~160°C, middle: 160~180°C, middle: 170~190°C, front: 170~190°C, nozzle: 190~215°C, mold: 30~60°C.
6. Use slow shooting speed or multi-level shooting speed, and the pressure should not be too high. It is recommended to use a large nozzle
7. Screw speed to match the cycle: the lower the back pressure, the better. (Available: PMMA, PP, LDPE, GPPS cleaning machine).

2. PP polypropylene

It is often called Baizhe glue, abbreviated: PP, PPR, PPN, PP-N, PP-K, PP-C, PP-HO, PP-CO.
1. The heat distortion temperature is 100℃, which can withstand boiling water, steam and disinfection.
2. It melts at about 170°C after heating with flame, the flame is faintly glowing, with yellowish blue color, and it still burns after leaving the fire. The smell is like a candle. It does not need to be cleaned with other materials when it is shut down.
3. Shrinkage: PP is a semi-crystalline thermal material, with a shrinkage rate of 1.8%~2.5%, a 24-hour shrinkage of 8.5%, and 98% in the first week. Put it in boiling water for 1 hour to complete. Note: Too long shrink time indicates an error in the injection molding process (such as high mold temperature, too low glue temperature, and too high pressure). If there is no excessive deformation in boiling water for 15 minutes, it means there is no problem in the injection molding process.
4. Adding 30% glass fiber (named PPGF30) can reduce the shrinkage to 0.7%.
5. Do not explode outdoors. It will be dissolved by aromatic or chlorinated carbon at a high temperature of 85°C; contact with copper-containing blended plastics at high temperatures will cause decomposition.
6. PP is a semi-crystalline thermal material, the mold temperature is 50℃, and general-purpose screws (L:D=20:1) can be used.
, Glue temperature: 220~275℃, do not exceed 275℃, otherwise the viscosity will change drastically and oxidation will occur.
8. Barrel material retention: 260℃ should not exceed 5~6 minutes, and 270℃ should not exceed 2~3 minutes.
9. Temperature setting value: rear: 190~230℃, middle: 200~240℃, middle: 210~260℃, front: 220~270℃, nozzle: 220~270℃, mold: 30~80℃.
10. Shooting speed: high speed (which can reduce internal stress and deformation), there are lines on the surface of the mold, and surface problems can be used at low speed and high mold temperature, and high pressure can be used.
11. Screw speed: in accordance with the cycle, the lower the back pressure, the better.

Three, HDPE high-density polyethylene

(Often called hard soft rubber)

1. HDPE is a semi-crystalline thermal plastic, with a shrinkage rate ranging from 2.0% to 5.0%, even 5%. The mold temperature has a great influence on the degree of shrinkage, and the mold temperature must be stable.

2. The mold temperature should be 20°C. Within 24 hours at this temperature, the product will absorb 0.01% water. If necessary, bake at 65°C/3 hours. Dry for 2 hours with the raw material beer, and bake for 3 hours when the sprue is added or the weather is humid from February to May.
3. General purpose screws (L:D=20:1) can be used.
4. Maintaining the pressure for a long time can ensure the stability of the product.
5. It is easy to burn when heated, the flame blue is yellowish, there is only a little smoke, there are burning glue drops, and it emits a waxy smell after extinguishing.
6. Applicable temperature: 220~260℃, if the temperature is 270℃, the machine can not be shut down for more than 5~6 minutes, if it is 280℃, it can not exceed 2~3 minutes.
7. Temperature setting: rear: 160~200℃, middle: 170~230℃, middle: 200~260℃, front: 220~280℃, nozzle: 210~270℃, mold: 10~60℃.
8. Shooting speed: high-speed injection or multi-stage injection molding can be used.
9. Screw speed coordination cycle: the lower the back pressure, the better.

Four, LDPE low density polyethylene

(Often called soft plastic flower material)

1. Large shrinkage: 5%~5.0%
2. It is easy to burn when heated, the flame blue is yellow with only a little smoke, there are burning glue drops dripping, and it emits a waxy smell after extinguishing.
3. The best mold temperature is 30℃. After 24 hours at room temperature, the water will absorb 0.02%. If necessary, it can be baked at 65℃/3 hours. The glue temperature is between 180~280℃. Dry for 2 hours with the raw material beer, and bake for 3 hours in February to May when the sprue is added or the weather is humid.
4. General purpose screws (L:D=20:1) can be used.
5. Material stopping time: at 270°C, the material residence time cannot exceed 5-6 minutes, if at 285°C, it cannot exceed 2-3 minutes.
6. Temperature setting: rear: 120~200℃, middle: 160~230℃, middle: 180~260℃, front: 200~280℃, nozzle: 210~270℃, mold: 10~60℃.
7. It can be used for high-speed injection or multi-level injection.
8. Screw speed coordination cycle: the lower the back pressure, the better.

Five, PS transparent styrene

(Often called hard rubber)

1. It only absorbs 0.04% of water after being immersed in water for 24 hours.
2. It is fragile, flammable, and easy to age. It is easy to turn yellow and fade when exposed to the sun for a long time.
3. PS will sink in water, and will soften and burn after heating with fire, giving out a black yellow flame and smell. The smell is especially obvious after the fire is extinguished, and it does not need to be cleaned with other materials.
4. Shrinkage 0.4%, 0.2% after adding glass fiber 25% GF.
5. Drying at 70°C (2-3H). Drying with raw material beer for 2 hours, and 3 hours when adding nozzle material or wet weather (from February to May).
6. Beer metal inserts: Preheat the metal to 80℃~120℃, remove the oil, and have grooves on the outer layer.
7. Applicable general screws: L: D=18:1
8. Melting temperature: 200℃~250℃a. High temperature will reduce the quality orientation, thus strengthening its anti-breaking (such as when ejecting) and thermal deformation resistance. b. If the temperature is 250°C, the residence time of the material cannot exceed 5 minutes, and if it is 275°C, it cannot exceed 1 to 2 minutes.
9. Pay attention to the control of hydraulic fluid temperature, material temperature, plastic temperature, and mold temperature.
10. Temperature setting: rear: 150~180℃, middle: 180~230℃, middle: 210~250℃, front: 210~280℃, nozzle: 210~280℃, mold: 10~80℃
11 , Rate of fire: high speed (no need for high pressure)
12. Rotation speed: can be very high (best to match the cycle)
13. Back pressure: usually use low back pressure (beer colored can be used)

Six, PMMA

(Acrylic or plexiglass)

1. The shrinkage rate is 4%~0.7%. It is easy to burn in case of fire. The flame is close to smokeless. After the fire is extinguished, it will smoke. The flame is blue and yellow, giving off a sweet fruit flavor with a little smoke. It will still burn after the fire is separated. No need to use other materials for cleaning.
2. After 24 hours at room temperature, absorb 0.3% of water. If necessary, bake at 75℃/2~4 hours. Dry with raw material beer for 2 hours, and bake for 3 hours in February to May when the sprue is added or the weather is humid.
3. Mold temperature should be 60℃, nozzle ≥5mm, melting temperature 210℃~270℃, if temperature is 260℃, material residence time should not exceed 8 minutes.
4. Temperature setting: rear: 150~210℃, middle: 170~230℃, middle: 180~250℃, front: 180~275℃, nozzle: 180~275℃, mold: 60~90℃.
5. Slow injection of glue can be used (to avoid high internal stress, multi-stage injection molding or gradual speed should be adopted, and product thickness should be slow.
6. Screw speed coordination cycle: the lower the back pressure, the better.

Seven, ABS

(Often called super non-shattered glue)

1. The shrinkage rate is 4%~0.8%, adding 20% ​​GF glass fiber, then 0.2%~0.4%.
2. The background color is ivory or white, the hot-melt viscosity decreases steadily with the increase of temperature, and the melting point is 175℃.
3. When burning, it will produce a yellow flame with black smoke, giving off a strong alkali smell similar to rubber. It is generally flammable and cannot be automatically extinguished.
4. Absorb 0.2~0.35% of water within 24 hours at room temperature. If necessary, bake at 80℃/2~4 hours. Dry it with raw material beer for 2 hours, and bake it for 4 hours from February to May when the sprue is added or the weather is humid. (Note: Must strictly abide by the first-in-first-out management system of goods.)
5. The mold temperature is preferably 60℃. Hot runner molds are not suitable for fire-resistant ABS.
6. Use slow glue back as much as possible, and the low-temperature barrel has low back pressure.
7. Impact resistance level: 220~260℃ is required, preferably 250℃.
Electroplating level: 250~275℃ is required, preferably 275℃.
Heat resistance grade: 240~280℃ is required, preferably 265~270℃.
Fire rating: 200~240℃ is required, preferably 220~225℃.
Transparent grade: 230~260℃ is required, 245℃ is better.
Glass fiber-containing grade: 230~270℃ is required, and the mold temperature is 60~95℃.
8. At 265°C, the barrel stays for no more than 5-6 minutes, and at 280°C it cannot be longer than 2 to 3 minutes.
9. The ABS material stays in the barrel for too long. Overheating of the barrel will cause no problem when the ABS product is ejected, but it may produce brown or tea streaks during the storage period. The difference in the residence time or the uncertainty of the cycle will cause the product to be stored. Discoloration occurred during the period.
10. Shooting speed: slow for fireproof grade (no decomposition), fast for heat resistant grade (reduce internal stress), to produce the best product, that is, with high gloss, high-speed multi-stage injection speed, and dry material , Melting glue and mold temperature should be high.
11. Screw speed: It is best to slow (cooperate with cycle) and low back pressure.
12. The properties of ABS material can remain unchanged at 40~100℃, and the heat change temperature is 100℃.

8. POM (often called Saigang)

1. Material properties: Even at 50℃, its impact resistance remains good. POM-H has the largest impact strength, warpage strength, fatigue resistance and hardness. POM-K has better thermal stability. Alkali resistance and hot water resistance. The above two are crystals and have low water absorption. The shrinkage rate is 2
2. POM is a highly crystalline material (about 80°C), and the shrinkage is quite high. Post-plastic shrinkage will occur within 48 hours. 0.1% high mold temperature will increase the actual shrinkage of the shrinkage, but will reduce the post-plastic shrinkage (Precision products need to use high mold temperature to produce stable products).
3. POM burns light blue, drips glue, there is not much residual material and smoke, and emits a strong formaldehyde odor after flameout. The melting point of POM-H is 175℃, and the melting point of POM-K is 164℃.
4. POM baked at 85℃/2~3 hours. POM-H/POM-K can be used at 215℃ (190~230℃), never exceed 240℃. Dry the raw material beer for 2 hours, and bake it for 3 hours when the sprue is added or the weather is humid from February to May.
5. If the equipment is good (no glue blocking point), POM-H can stay at 215°C for 35 minutes, and POM-K can stay at 205°C for 20 minutes without decomposition.
Be careful to clean up. Put the waste into cold water. At the molding temperature, the melt cannot stay in the barrel for more than 20 minutes. POM-K can stay at 240°C for 7 minutes or 210°C for 20 minutes.
6. Temperature setting: rear: 165~210℃, middle: 162~200℃, middle: 170~210℃, front: 180~215 combustion, nozzle: 170~215℃, mold: 40~120℃.
7. Shooting speed: (filling speed) medium and fast, too slow will cause peeling, too fast will damage the gate.
8. Screw speed coordination cycle: The lower the back pressure, the better. The washing machine is best to be cleaned with polyolefin (POLYDEFIN), and the barrel cannot be shared with PVC or fireproof. Even if it is used, it must be cleaned thoroughly, otherwise it will explode.

Nine, nylon 6 (NYLON6, PA66): abbreviation PA6

1. When burning, the flame is blue, with yellow edges, white smoke, easy to extinguish, and smells of burning hair or horns.
2. The melting point of PA6 is 220℃, PA66 is 265℃, and it is baked at 80℃/2~4 hours. Under the same environment, PA6 absorbs more water than PA66, which is 2.5% and 1.5% respectively. Dry for 2 hours with raw material beer, such as adding sprue or bake for 3 hours from February to May in wet weather.
3. The mold temperature is 40~80℃, the glue temperature is 250℃, and the reinforced grade needs 270~280℃.
4. Temperature setting (unenhanced level): rear: 220~240℃, middle, 230~250℃, middle: 230~260℃, front: 230~270℃, nozzle: 220~260℃, mold: 60~ 90°C.
5. The residence time of the material in the barrel: no more than 20 minutes at 300°C, and the temperature can be lowered to 200°C if necessary.
6. The faster the injection speed, the better (filling speed). If you want to make the enhanced surface smooth but dull, you must shoot the material slowly. High-speed injection can make the surface smooth but with bubbles.
7. Screw speed: It can be matched with the cycle. The fire rating should not be too fast. The lower the back pressure, the better. The washing machine can be cleaned with HDPE or PP.

10. PA66 (nylon)

1. PA66 water absorption: the volume of each 1% water absorption increases by 0.003in, and the water absorption is 2.5% at a relative humidity of 50% and an air temperature of 23°C.
2. The melting point of PA66 is 265°C. It melts when burned, turns dark and boils. The flame blue is yellow with white smoke, which is easy to extinguish and emits the smell of celery.
3. Drying material: It can be baked at 85℃ for 2 to 4 hours in an exhausted hot air furnace. Dry the raw material beer for 2 hours, and bake it for 4 hours from February to May when the sprue is added or the weather is humid.
4. The mold temperature should be 40~90℃, the melt temperature should be 260~290℃, preferably 280℃, the lubrication grade and fireproof grade should be low temperature, such as 260~275℃.
5. Temperature setting: unenhanced level: rear: 275~280℃, middle: 270~285℃, front: 265~285℃, nozzle: 260~280℃, mold: 20~100℃.
Reinforcement level: Rear: 280~290℃, Middle: 285~290℃, Middle: 275~300℃, Front: 275~290℃, Nozzle: 270~280℃, Mould: 55~95℃.
6. Barrel residence time: If the melt temperature is 300℃, it should not exceed 15 minutes, otherwise the quality will be degraded and the product will fade and become fragile.
7. Shooting speed: Fiber filler grade and thin rubber products need to shoot glue quickly.
8. Screw speed: slow or moderate, fiber filler should be slow, the lower the back pressure, the better.

Eleven, PA11, PA12

(Nylon 11/Nylon 12)

1. Both are linear semiconducting thermoplastics with properties between PA6 and PE.
2. The amount of shrinkage varies from 0.5% to 2%, depending on the grade and the thickness of the product due to the processing conditions. The shrinkage will not increase with the increase of mold temperature.
3. PA11 and PA12 will sink in water, all nylon materials will sink in water, and PE will float in water, distinguish each nylon and observe its melting point.
4. Baking: 85℃/3~5 hours, melting temperature 240~300℃, preferably 260℃, standard grade should not exceed 310℃, fireproof grade should not exceed 270℃. Dry it with raw material beer for 3 hours, and bake it for 5 hours from February to May when the sprue material is added or the weather is humid.
5. Temperature setting: unenhanced level: rear: 210~240℃, middle: 220~250℃, middle: 230~260℃, front: 240~270℃, nozzle: 230~270℃, mold: 30~100 ℃.
Reinforcement level: rear: 240~250℃, middle: 240~260℃, middle: 250~270℃, front: 260~280℃, nozzle: 250~260℃, mold: 50~100℃.
6. Barrel residence time: the shorter the better (less than 3 minutes).
7. The rate of fire is not important. High speed will make the surface of the product better.
8. Screw speed: high speed is available.
9. If the product needs high impact force, it is best to use high temperature and low pressure. High mold temperature will help thick parts flow and increase the luster of the filling level.

12. FEP

1. It is not easy to catch fire, and there is very little smoke.
2. Baking: 150℃/2~4 hours. Dry for 2 hours with the raw material beer, and bake for 4 hours when the sprue is added or the weather is wet from February to May.
3. Smoking is strictly prohibited when using this material. If you smoke, you will fall into a cold-like state (not even you can bring cigarettes).
4. Barrel residence time: no more than 5 minutes at 390°C, no more than 25 minutes at 370°C.
5. Mold temperature must be above 100~130℃, temperature setting: rear: 315~330℃, middle: 320~340℃, middle: 330~350℃, front: 345~370℃, nozzle: 345~370℃.
6. The injection speed should be slow, just fill the mold with the slowest speed.
7. The slower the glue back, the better, and the back pressure can be higher.

13. PBT

1. It is a semi-crystalline plastic, the injection cycle can be completed quickly (mold allows), and it is difficult to clean the barrel and screw.
2. The melting point is 225°C (PET is 260°C). When burning, the flame is white and emits black smoke. It will be automatically extinguished away from the fire source, forming a smooth surface and leaving carbon stains.
3. Baking: 120℃/3~5 hours. Dry the raw material beer for 2 hours, and bake it for 5 hours when the sprue is added or the weather is humid from February to May.
4. High mold temperature can reduce post-plastic shrinkage. To avoid long dwell time of the barrel, the melting temperature ranges from 230 to 260°C, preferably 240 to 245°C.
5. Temperatures above 270°C will cause rapid degradation of plastics, stay at 290°C for less than 2 minutes, 220°C for about 12 minutes, PBT has poor heat resistance, and glass fiber-reinforced materials must have a higher temperature than unreinforced materials (approximately 10°C).
6. High-speed injection glue (especially GF grade) should be used.
7. The lower the glue back speed, the better, the back pressure is 7BAR.
8. Due to overheating and degradation, scrape off the residue of the screw and barrel, remove the solidified melt, and wash the machine with HDPE or PP.

14. PC (often called bulletproof glue)

1. PC belongs to the polyester category, and the carbonated cheese combination is formed by the aromatic combination, which burns slowly (the fireproof grade is V1 or even V0).
2. Shrinkage: 0.006~0.008in (0.6%~0.8%), 30% glass fiber PC has 0.003~0.005in, PC/PBT blend has 0.008~0.01in.
3. Do not keep in contact with hot water above 60℃ for a long time. When PC burns, it will emit pyrolysis gas. The plastic will scorch and foam, but it will extinguish when it is not on fire. It will extinguish when it is away from the fire source. It will emit a rare and thin phenol smell, the flame is yellow, and the light is light. Jet black, the temperature reaches 140 ℃ to begin to soften, 220 ℃ melts, can absorb infrared spectrum.
4. Baking ingredients: 120℃/2~4 hours, PC/PBT blends are baked at 110℃, PC/ABS blends are baked at 110℃/1 hour, mold temperature is 40~90℃, melt temperature is 250℃. Dry for 2 hours with the raw material beer, and bake for 4 hours when the sprue is added or the weather is wet from February to May.
5. The glue injection machine should be disassembled regularly to check its melting situation, because the end of the bubbles will be displayed on the surface of the product, and low-quality products may be produced (the appearance is still beautiful). The melting temperature of PC/ABS blends cannot exceed 280℃, the same is true for PC/PBT, and GFPC is between 305~330℃.
6. Temperature setting:
unenhanced level: rear: 275~300℃, middle: 280~310℃, middle: 285~325℃, front: 285~315℃, nozzle: 280~310℃, mold: 80~120 ℃.
Reinforcement level: rear: 300~315℃, middle: 305~320℃, middle: 310~345℃, front: 315~330℃, nozzle: 320~330℃, mold: 70~130℃.
7. Barrel residence time: it will degrade at 320℃, emit carbon dioxide, turn yellow, and reduce the mechanical properties. The processing temperature range should be avoided too long, and the residence time PC/PBT should be less than 7 minutes.
8. The faster the injection speed, the better, the slower the glue back speed, and the low back pressure (10BAR) helps prevent degradation caused by vaporization.
9. Do not use LDPE, POM, ABS, PA to wash the machine when it is shut down. These materials will contaminate PC and degrade it. Use HDPE, PS, PMMA to clean it.
10. Do not use a torch to clean the metal parts of the injection molding machine. It can be heated at 400℃ and then cleaned with a steel wire tool.

15. PEI

1. Shrinkage 0.006in (0.6%), adding 30% glass fiber can reduce 0.2%~0.4%.
2. The background color is orange/brown/amber, it will emit a yellow flame when it is in fire, and it will go out automatically after leaving the fire.
3. The mold temperature is 65~175℃, 140℃ is the best, the water absorption is 0.25% within 24 hours at room temperature (the saturated water absorption is about 1.25%).
4. Baking: 150℃/3~5 hours. If the rubber has foam or the product has silver stripes, the material must have a longer drying time. Dry the raw material beer for 3 hours, and bake it for 5 hours when the sprue is added or the weather is wet from February to May.
5. If the barrel is not good, the product will have black spots. It is best to use a short nozzle. Since high temperature may cause degradation, the amount of glue shot must be matched with the barrel of the machine.
6. Melting temperature: 340~425℃, about 380℃ is the best.
7. If the temperature is 360°C, the residence time cannot exceed 10 minutes, and if the temperature is 400°C, the residence time cannot exceed 6 minutes.
8. The shooting speed is moderate to high speed, the glue back speed is matched with the cycle, and the back pressure is free. The washing machine can use HDPE, GFPC, PMMA (PMMA is only used at low temperature), and start cleaning at the processing temperature. Change the temperature to 260°C until the PEI is completely cleaned, continue to operate for 10 minutes, and then clean again, until the bottom is cleared.
9. The traces of stress can be found by immersing PEI in benzene alcohol. Stress above 2500PSI can be revealed after immersing in benzene alcohol for 15-20 seconds. Potassium dioxide is even more powerful, only 30 seconds/1000PSI or more. The stress can be revealed.

16. PET or PETP

1. To make the plastic strong, a high mold temperature (130°C) must be used.
2. Containing 36% GF, the shrinkage in the equilibrium flow direction is 0.2%.
3. It can't resist hot water and steam, so don't use it continuously in hot water above 50℃.
4. There are amorphous and crystalline, transparent and opaque.
5. The crystal is easy to burn, and the flame is as tiny as a candle, with very little smoke and vapor. After the flame is extinguished, it will emit white smoke, and the burnt edge will expand and become light.
6. Baking: 135℃/3~5 hours, the mold temperature of the crystal is 135℃, and the nozzle is above 3mm. Dry the raw material beer for 2 hours, and bake it for 5 hours when the sprue is added or the weather is humid from February to May.
7. Temperature setting:
after crystalline ARINTE: 270~280℃, middle: 270~285℃, middle: 270~290℃, front: 270~290℃, nozzle: 265~280℃, mold: 130~140℃ .
Crystal grade RYNITE: rear: 280~290℃, middle: 285~295℃, middle: 290~300℃, front: 290~300℃, nozzle: 290~300℃, mold: 85~120℃.
Amorphous PET: rear: 210~240℃, middle: 220~250℃, middle: 230~260℃, front: 235~275℃, nozzle: 230~270℃, mold: 15~25℃ (mainly used for manufacturing Bottle)
8. Try to avoid the temperature above 300℃. When it is below 290℃, it only contains 50% GF. The PET barrel should not stay for less than 4 minutes. The electric heat should be reduced immediately after overtime, and the machine should be washed with PE.
9. The rate of fire should be as fast as possible, the best is to complete in 4 seconds, the screw speed is 100RPM, the lower the back pressure, the better, usually without back pressure, use HDPE or PS to wash the machine.

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