Common plastic properties

May 10, 2019

Common plastic properties
 

ABS plastic (acrylonitrile butadiene styrene)
Specific gravity: 1.05 g / cm 3
Molding shrinkage: 0.4-0.7%
Molding temperature: 200-240 ° C
Drying conditions: 80-90 ° C for 2 hours

 

Material properties:
1. Good comprehensive performance, high impact strength, chemical stability and good electrical performance.
2, and 372 plexiglass has good weldability, made into two-color plastic parts, and can be chrome-plated and painted.
3, has high impact, high heat, flame retardant, enhanced, transparent and other levels.
4, the fluidity is a little worse than HIPS, better than PMMA, PC, etc., and good flexibility.
Suitable for general mechanical parts, wear-resistant parts, transmission parts and telecommunications parts.

Molding performance:
1. Amorphous material, medium fluidity, large moisture absorption, must be fully dried, and the plastic parts with gloss on the surface must be preheated and dried for 80-90 degrees for 3 hours.
2, should take high material temperature, high mold temperature, but the material temperature is too high and easy to decompose (decomposition temperature is >270 degrees). For higher precision plastic parts, the mold temperature should be 50-60 degrees, high gloss. For thermoplastic parts, the mold temperature should be 60-80 degrees.
3. If you need to solve the water trap, you need to improve the fluidity of the material, adopt high material temperature, high mold temperature, or change the water level.
4. If the heat-resistant grade or flame-retardant grade material is formed, the plastic decomposition product will remain on the surface of the mold after 3-7 days of production, which will cause the surface of the mold to be bright. It is necessary to clean the mold in time, and the surface of the mold needs to increase the exhaust position.

 

PP plastic (polypropylene)
Specific gravity: 0.9-0.91 g / cm 3
Molding shrinkage: 1.0-2.5%
Molding temperature: 160-220 ° C

 

Material properties:
Low density, strength stiffness, hardness and heat resistance are better than low-pressure polyethylene, can be used at about 100 degrees. Has good electrical properties and high-frequency insulation is not affected by humidity, but becomes brittle at low temperature, not resistant to mold aging .
Suitable for making general mechanical parts, corrosion resistant parts and insulating parts.

Molding performance:
1. Crystallized material has low hygroscopicity and is prone to rupture of the melt. It is easy to decompose in contact with hot metal for a long time.
2, good fluidity, but the shrinkage range and shrinkage value is large, easy to shrink holes, dents, deformation.
3, the cooling speed is fast, the pouring system and the cooling system should be slowly dissipated, and pay attention to control the molding temperature. The direction of the material is low and the direction is obvious. Especially at low temperature and high pressure, when the mold temperature is lower than 50 degrees, the plastic parts are not smooth and easy to produce. Poor welding, leaving marks, warping deformation is easy to occur above 90 degrees.
4, plastic wall thickness must be uniform, to avoid lack of glue, sharp corners, to prevent stress concentration.

 

PMMA plastic (plexiglass) (polymethyl methacrylate)
Specific gravity: 1.18 g / cm 3
Mold shrinkage: 0.5-0.7%
Molding temperature: 160-230 ° C
Drying conditions: 70-90 ° C 4 hours

 

Material properties:
Excellent transparency, high strength, certain heat and cold resistance, corrosion resistance, good insulation, comprehensive performance over polystyrene, but brittle, easy to melt in organic solvents, such as light-transmitting materials, surface hardness Slightly lower, easy to wipe flowers.
Suitable for making transparent insulating parts and parts with high strength.

Molding performance:
1. Amorphous material, large moisture absorption, need to be dried, not easy to decompose, medium in fluidity, easy to cause poor filling, sticking mold, shrinkage, weld line and so on.
2, high pressure injection, high temperature and high mold temperature without defects, to increase fluidity, reduce internal stress, improve transparency and strength. The surface of the mold casting system should be smooth and the draft is large. Eject the top evenly. Also set the exhaust port to prevent foaming.

 

POM plastic (polyoxymethylene)
Specific gravity: 1.41-1.43 g / cm 3
Molding shrinkage: 1.2-3.0%
Molding temperature: 170-200 ° C
Drying conditions: 80-90 ° C for 2 hours

 

Material properties:
Good comprehensive performance, high strength, high stiffness, good wear resistance, low water absorption, good dimensional stability, but poor thermal stability, easy to burn, easy to age in the atmosphere.
Suitable for making wear-resistant parts, transmission parts, and parts such as chemicals and instruments.

Molding performance:
1. Crystallized material, the melting range is narrow, the melting and solidification are fast, and the crystallization occurs when the material temperature is slightly lower than the melting temperature. Medium mobility. Low moisture absorption, no drying treatment.
2. The friction coefficient is low and the elasticity is good. The surface of the plastic part is prone to surface defects of wrinkles.
3, very easy to decompose, the decomposition temperature is 240 degrees. Irritating and corrosive gases occur during decomposition. Therefore, the mold steel should be made of corrosion-resistant materials.

 

PA plastic (nylon) (polyamide)
Specific gravity A6-1.14g/cm3 PA66-1.15g/cm3 PA1010-1.05g/cm3
Molding shrinkage A6-0.8-2.5% PA66-1.5-2.2%
Molding temperature: 220-300 ° C
Drying conditions: 100-110 ° C 12 hours

 

Material properties:
Tough, wear-resistant, oil-resistant, water-resistant, anti-enzytic, but absorbent. Nylon 6 has good elasticity, high impact strength, high water absorption. Performance of nylon 66 is better than nylon 6, high strength, good wear resistance. Nylon 610 is similar to nylon 66. However, the water absorption is small, the rigidity is low, the nylon 1010 is translucent, the water absorption is small, and the cold resistance is good.

Suitable for general mechanical parts, wear-resistant parts, transmission parts, and chemical, electrical, instrumentation and other parts.

Molding performance:
1. Crystallized material, the melting point is higher, the melting temperature range is narrow, the thermal stability is poor, the material temperature exceeds 300 degrees, and the residence time exceeds 30 minutes. It is easier to absorb moisture and needs to be dried. The water content should not exceed 0.3%.
2, good liquidity, easy to overflow. It is advisable to use a self-locking nozzle and it should be heated.
3. The molding shrinkage range and shrinkage rate are large, the directionality is obvious, and shrinkage and deformation are easy to occur.
4. The mold temperature is selected according to the wall thickness of the plastic part in the range of 20-90 degrees. The injection pressure is selected according to the type of the injection machine, the material temperature, the shape of the plastic part, the mold casting system, and the molding cycle is selected according to the wall thickness of the plastic part. When the viscosity of the resin is small, the injection and cooling time should be long, and white oil is used as a release agent.
5, the form and size of the mold casting system, increase the flow channel and gate size can reduce shrinkage.

 

PC plastic (polycarbonate)
Specific gravity: 1.18-1.20 g / cm 3
Mold shrinkage: 0.5-0.8%
Molding temperature: 230-320 ° C
Drying conditions: 110-120 ° C 8 hours

 

Material properties:
High impact strength, good dimensional stability, colorless and transparent, good coloring, good electrical insulation, corrosion resistance and wear resistance, but poor self-lubrication, stress cracking tendency, high temperature easy hydrolysis, poor compatibility with other resins .

Suitable for making small transparent parts and impact resistant parts of instrument small parts.

Molding performance:
1. Amorphous material, good thermal stability, wide forming temperature range and poor fluidity. Low moisture absorption, but sensitive to water, must be dried. The molding shrinkage rate is small, and it is prone to melt cracking and stress concentration. Therefore, the molding conditions should be strictly controlled, and the plastic parts must be annealed.
2, high melting temperature, high viscosity, more than 200g of plastic parts, it is advisable to use a heated extension nozzle.
3, the cooling speed is fast, the mold casting system is based on the principle of coarse and short, it is better to set the cold material well, the gate should be large, and the mold should be heated.
4, the material temperature is too low will cause lack of material, plastic parts are dull, the material temperature is too high, easy to overflow, plastic parts foaming. When the mold temperature is low, the shrinkage rate, elongation, impact strength are high, and the bending, compressive and tensile strengths are low. When the mold temperature exceeds 120 degrees, the plastic parts cool slowly and are easily deformed and stuck.

 

PSU plastic (polysulfone)
Specific gravity: 1.25-1.35 g / cm 3
Mold shrinkage: 0.5-0.7%
Molding temperature: 290-350 ° C
Drying conditions: 130-150 ° C 4 hours

 

Material properties:
1. Polysulfone is amber transparent solid material with high hardness and impact strength, non-toxic, heat-resistant, cold-resistant and aging-resistant. It can be used for a long time at -100--175 degrees. It is resistant to the corrosion of inorganic acid and alkali salts, but not to aromatic hydrocarbons and halogenated hydrocarbons. Polyarylsulfone has high hardness, radiation resistance, heat resistance and cold resistance, and is self-contained. It can be used for a long time at -100-175 degrees.
2, through the glass fiber reinforced modification can greatly improve the wear resistance of the material.
3, polysulfone and ABS, polyimide, polyetheretherketone and fluoroplastics can be made into polysulfone modified products, mainly to improve its impact strength and elongation, solvent resistance, environmental resistance, processing Performance and platability. Such as PSF / PBT, PSF / ABS, PSF + mineral powder.

use:
1. It is suitable for making heat-resistant parts, insulating parts, wear-reducing parts, instrument parts and medical equipment parts. Polyaryl sulfone is suitable for making low-temperature working parts.
2, polysulfone is commonly used in the electronics industry to manufacture integrated circuit boards, coil tube holders, contactors, sleeves, capacitor films, high performance alkaline battery housings.
3. Polysulfone is used in household appliances for microwave oven equipment, coffee heaters, humidifiers, hair dryers, steam dryers, beverages and food dispensers. It can also be used as a substitute for non-ferrous metals for precision structural parts such as watches, copiers, and cameras.
4. Polysulfone has passed the relevant regulations in the field of medicine and food in the United States and can replace stainless steel products. Due to its resistance to steam, hydrolysis, non-toxicity, high temperature steam sterilization, high transparency and good dimensional stability, polysulfone can be used as a surgical tool tray, sprayer, fluid controller, heart valve, pacemaker, gas mask, Tooth tray and so on.

Molding performance:
1. Amorphous material, large moisture absorption, water absorption rate 0.2%-0.4%, sufficient to dry before use, and prevent moisture absorption. Ensure that the water content is below 0.1%.
2, the molding performance is similar to PC, the thermal stability is poor, and decomposition begins at 360 degrees.
3, poor fluidity, fast cooling, it is best to use high temperature and high pressure molding. The mold should have sufficient strength and rigidity. Set the cold well, the flow path should be short, and the gate size should be 1/2-1/3 of the wall thickness of the plastic part.
4. In order to reduce the internal stress generated by the injection molded product, the mold temperature should be controlled at 100-140 degrees. After molding, it can be annealed glycerin bath annealing treatment, 160 degrees, 1-5 minutes; or take an air bath 160 degrees, 1-4 hours. The annealing time depends on the size and wall thickness of the article. 5. Polysulfone is close to Newtonian in the molten state. Similar to polycarbonate, the fluidity is sensitive to temperature. In the range of 310-420 degrees, the fluidity is doubled for every 30 degrees of temperature increase. Therefore, the molding fluidity is improved mainly by increasing the temperature during molding.

 

PPS plastic (polyphenylene sulfide)
Specific gravity: 1.36 g / cm 3
Mold shrinkage: 0.7%
Molding temperature: 300-330 ° C

 

Material properties:
1, electrical insulation (especially high-frequency insulation) is excellent, white is hard and brittle, falling on the ground with metal sound, light transmittance is second only to plexiglass, coloring water resistance, chemical stability. It has excellent flame retardancy and is non-combustible plastic.
2, the strength is general, the rigidity is very good, but the quality is brittle, easy to produce stress brittle fracture, not resistant to organic solvents such as benzene. Gasoline. The long-term use temperature can reach 260 degrees, and it is stable in 400 degrees of air or nitrogen. After being modified by adding glass fiber or other reinforcing materials, the impact strength can be greatly improved, heat resistance and other mechanical properties are also improved, the density is increased to 1.6-1.9, and the molding shrinkage is as small as 0.15-0.25%.
use

Suitable for making heat-resistant parts, insulating parts and chemical instruments, optical instruments and other parts.

Molding performance:
1. Amorphous material, small moisture absorption, but should be formed after drying.
2. The fluidity is between ABS and PC. It has fast solidification, small shrinkage and easy decomposition. It uses high injection pressure and injection speed. The mold temperature is taken from 100 to 150 degrees. The main channel taper should be large and the runner should be short.

 

PPO plastic (MPPO) (polyphenylene oxide)
Specific gravity: 1.07 g / cm 3
Molding shrinkage: 0.3-0.8%
Molding temperature: 260-290 ° C
Drying conditions: 130 ° C 4 hours

 

Material properties:
1. It is a white granule. Good comprehensive performance, can be used in 120 degree steam, good electrical insulation, low water absorption, but there is a tendency to stress cracking. Modified polyphenylene ether eliminates stress cracking.
2. Excellent electrical insulation and water resistance, good dimensional stability. Its dielectric properties rank first in plastics.
3. MPPO is a modified material prepared by blending PPO and HIPS. Currently, the materials on the market are all such materials.
4, has a higher heat resistance, glass transition temperature of 211 degrees, melting point of 268 degrees, heating to 330 degrees has a tendency to decompose, the higher the PPO content, the better the heat resistance, the heat distortion temperature can reach 190 degrees.
5, good flame retardancy, self-interest, and moderate flammability after mixing with HIPS. Lightweight, non-toxic for the food and pharmaceutical industries. Poor light resistance, will change color when used in the sun for a long time.
6, can be blended with ABS, HDPE, PPS, PA, HIPS, glass fiber, etc.

Uses:
1. It is suitable for the manufacture of heat-resistant parts, insulation parts, wear-reducing parts, transmission parts, medical and electronic parts.
2, can be used for gears, blades, valves and other parts used at higher temperatures, can be used instead of stainless steel.
3, can make screws, fasteners and connectors.
4. Electrical parts of motors, rotors, casings and transformers.

Molding performance:
1. Non-crystalline material, low moisture absorption.
2, poor fluidity, similar to Newtonian fluid, viscosity is sensitive to temperature, the thickness of the product is generally above 0.8 mm. It is easily decomposed and generates corrosive gases when decomposed. The molding temperature should be strictly controlled, the mold should be heated, and the casting system should have a small resistance to the flow.
3, the water absorption of polyphenylene ether is very low 0.06%, but a small amount of water will cause the surface of the product to appear non-smooth, such as dry, preferably dry

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