The difference between ABS plastic and PP plastic
ABS plastic-performance
The appearance of ABS is opaque and ivory colored pellets, and its products can be colored colorfully and have high gloss. The relative density of ABS is about 1.05, and the water absorption is low. ABS has a good combination with other materials and is easy to surface print, coating and plating treatment. The oxygen index of ABS is 18-20, which is a flammable polymer. The flame is yellow, has black smoke, and emits a special cinnamon smell.
Mechanical properties
ABS has excellent mechanical properties, its impact strength is very good, and it can be used at extremely low temperatures; ABS has excellent wear resistance, good dimensional stability, and oil resistance, and can be used for bearings under medium loads and speeds. ABS has higher creep resistance than PSF and PC, but less than PA and POM. The flexural strength and compressive strength of ABS are the worst among plastics. The mechanical properties of ABS are greatly affected by temperature.
Thermal performance
The thermal deformation temperature of ABS is 93 ~ 118 ℃, and the product can be increased by about 10 ℃ after annealing treatment. ABS can still show some toughness at -40 ℃, and it can be used in the temperature range of -40 ~ 100 ℃.
Electrical performance
ABS has good electrical insulation and is almost independent of temperature, humidity and frequency. It can be used in most environments.
Environmental performance
ABS is not affected by water, inorganic salts, alkalis, and various acids, but is soluble in ketones, aldehydes, and chlorinated hydrocarbons. Stress cracking will occur due to erosion by glacial acetic acid and vegetable oil. ABS has poor weather resistance and is prone to degradation under the action of ultraviolet light; after half a year outdoors, the impact strength is reduced by half.
Processability of ABS plastic
BSABS, like PS, is a thermoplastic with excellent processability and can be processed by common processing methods.
ABS has better melt fluidity than PVC and PC, but worse than PE, PA and PS, similar to POM and HIPS. The flow characteristics of ABS are non-Newtonian fluids; its melt viscosity is related to processing temperature and shear rate , But more sensitive to shear rate.
ABS has good thermal stability and is not prone to degradation. ABS has a high water absorption rate and should be dried before processing. The drying conditions of general products are temperature 80 ~ 85 ℃, time 2 ~ 4h; for special requirements products (such as electroplating), the drying conditions are temperature 70 ~ 80 ℃, time 18 ~ 18h. ABS products are prone to internal stress during processing. The magnitude of the internal stress can be inspected by immersion in glacial acetic acid. If the stress is too large and the product is absolutely forbidden from stress cracking, it should be annealed. The specific conditions are hot air circulation at 70 ~ 80 ℃. Dry in the oven for 2 ~ 4h, and then cool to room temperature.
PP plastic polypropylene
PP plastic polypropylene
Features
Non-toxic, odorless, 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 temperatures , Non-wear-resistant, easy to age. Suitable for making general mechanical parts, corrosion-resistant parts and insulation parts. Common acid and alkali organic solvents have little effect on it and can be used in utensils. Forming characteristics
1. Crystal material, low wetness, easy to melt rupture, easy to decompose in long-term contact with hot metal. 2. Good fluidity, but the shrinkage range and shrinkage value are large, and shrinkage holes, dents and deformation are easy to occur.
3. The cooling speed is fast. The pouring system and cooling system should slowly dissipate heat, and pay attention to controlling the molding temperature. The material temperature is easy to be oriented at low temperature and high pressure. When the mold temperature is lower than 50 degrees, the plastic part is not smooth, and it is easy to produce poor welding and flow marks. Above 90 degrees, warping deformation is easy to occur.
4. Plastic wall thickness must be uniform to avoid lack of glue and sharp corners to prevent stress concentration. pp characteristics
Rhenium PP is a semi-crystalline material. It is harder than PE and has a higher melting point. Because homopolymer-type PP is very brittle at temperatures above 0C, many commercial PP materials are random copolymers with 1 to 4% ethylene or clamp copolymers with higher ethylene content. Polymer PP materials have lower heat distortion temperature (100 ° C), low transparency, low gloss, and low rigidity, but have stronger impact strength. The strength of PP increases with increasing ethylene content. The Vicat softening temperature of PP is 150C. Due to its high crystallinity, this material has good surface stiffness and scratch resistance. PP does not suffer from environmental stress cracking. Generally, PP is modified by adding glass fibers, metal additives or thermoplastic rubber. The flow rate MFR of PP ranges from 1 to 40. Low MFR PP materials have better impact resistance but lower ductility. For materials of the same MFR, the copolymer type is stronger than the homopolymer type. Due to crystallization, the shrinkage of PP is quite high, generally 1.8 ~ 2.5%. And the directional uniformity of shrinkage is much better than materials such as PE-HD. Adding 30% glass additives can reduce the shrinkage to 0.7%. Both homopolymer and copolymer PP materials have excellent moisture absorption resistance, acid and alkali corrosion resistance, and solvent resistance. However, it is not resistant to aromatic hydrocarbon (such as benzene) solvents, chlorinated hydrocarbon (carbon tetrachloride) solvents, and the like. PP is not as resistant to oxidation at high temperatures as PE.
This is Nancy, I have 6 years experience as a mold designer and 3 years working as a project manager. Sales Engineer/Project Engineer for ABIS Mold. Please contact with me use if you have any needs and requirements with plastic injection molds. I look forward to talking with you further.Nancy email: nancy@abismold.com.
wechat / Call : 0086-17727582624 Linkedin:Nancy Zhang
