Introduction to plastic materials----
1 Classification of commonly used raw materials for plastics
2 Terminology of commonly used raw materials for plastics
3 Definitions of general materials and engineering materials
4 Properties of commonly used general plastics
5 Properties of commonly used engineering plastics

 

Classification by degree of heat exposure of resin
1. Thermoplastic plastic materials
2. Thermosetting plastic materials
Classification by plastic use
1. General plastic materials
2. Engineering plastic materials

1: Thermoplastic plastics - plastics soften when heated, and can be in a viscous flow state when temperature rises to a certain value. When temperature drops (referring to room temperature), plastics become hard. It can soften again when heated again and harden again after cooling, and this can be repeated many times.
2: Thermosetting plastics - plastics soften when heated for the first time, solidify and become rigid when cooled, no longer soften when heated again, and decompose when temperature exceeds a certain value.
3: General plastics - large output, large amount, low price, mainly used in manufacture of daily necessities.
4: Engineering plastics - usually refers to plastics with high mechanical properties, high temperature and corrosion resistance, used as structural materials in various projects.

Classification of plastics
1. At present, plastics have developed into more than 300 kinds, and there are more than a dozen most commonly used ones.
Generally divided into general plastics and engineering plastics:
2. General plastics can only be used as general non-structural materials. They have large output, relatively low price, and general performance. They are mostly used to make daily necessities. (Such as: PE, PP, PVC, PS, PMMA, etc.)
3. Engineering plastics refer to those with high mechanical properties, high temperature resistance and corrosion resistance. They can be used as structural materials and have excellent comprehensive properties (including: mechanical properties, electrical properties, heat resistance, chemical resistance, etc.). They can maintain this property well in a wide temperature range and for a long time, can withstand mechanical stress, harsh chemical and physical environments. Seven major engineering plastics that have been recognized for long-term use are: ABS, PC, POM, PA, PET, PBT, PPO, etc. Output of engineering plastics is relatively small and price is relatively expensive.

 

1.PE-full name is Polyethylene
1.1: Material Introduction
It can be divided into high-pressure polyethylene, medium-pressure polyethylene, and low-pressure polyethylene. High-pressure polyethylene has poor strength but good flexibility, impact resistance and transparency.
Also called low-density polyethylene. (LDPE). Low-pressure polyethylene has poor flexibility than high-pressure polyethylene and hard texture. Also called high-density polyethylene (HDPE). Polyethylene is milky white and translucent, will burn when exposed to fire.
Shrinkage: 12‰-15‰

 

1.2: Usage method
Melting point temperature: 112-135℃
Barrel temperature: 200℃-240℃
Mold temperature: 20℃-60℃
Drying material: No need to dry material. If storage conditions are not good, it can be dried at 80℃
1.3: Material recycling: 100% recyclable
1.4: Molding note: PE material has good fluidity. Avoid high-speed and high-pressure injection to avoid flashing of product.
1.5: Shutdown matters: When shutting down, inject material in barrel and lower temperature. No other washing materials are needed to clean machine, and spray mold with anti-rust oil.
1.6: Application: Injection molding into daily necessities: bottle shells, toys, stationery, basins and bowls, and some parts of instruments and cars, extrusion and calendering into various films, blow molding into various instrument containers, extrusion into various profiles.

 

PVC-full name: Poly-vinylchloride
2.1: Material introduction PVC is a colorless and transparent body, and is usually supplied as white powder. PVC begins to soften at 65℃-85℃, is in a molten state at 150℃-170℃, decomposes and releases toxic hydrogen chloride above 190℃. Because it contains a high content of chlorine, it has characteristics of flame retardancy and self-extinguishing
2.2: According to different plasticizers added to composition, it can be made into soft PVC and hard PVC. Soft PVC (PPVC), hard PVC (PVC-U) shrinkage rate: (soft) 10‰-25‰ (hard) 5‰-7‰
2.3: Usage:
Melting point temperature: 150℃, barrel temperature: 150℃-200℃ mold temperature: 30℃-50℃
Drying material: It is not necessary to dry material; if storage conditions are not good, it can be dried at 70℃ for 1H

 

2.4: Material recycling: Sprue material can be recycled without thermal decomposition.
2.5: Molding precautions: PVC is very sensitive to temperature, and temperature must not be set above 195℃ during injection molding. If temperature is too high, material will decompose and produce hydrogen chloride gas, which will cause serious damage to human body and equipment. At the same time, please note that production process cannot be stopped for more than 3 minutes, otherwise material will decompose immediately.
2.6: Stoppage matters: When stopping, barrel must be cleaned with machine cleaning material immediately, mold surface must be wiped clean and sprayed with anti-rust oil immediately to prevent mold from rusting due to corrosion.
2.7: Safety tips: Production workshop using PVC materials must have good air flow to avoid damage to human body.
2.8: Application: Chemical-resistant containers, sewer pipes, fireproof window frames and decorations

 

TPE-full name: Thermoplastic Elastomer
3.1: Material introduction: Material is available in semi-transparent, highly transparent, white, and black. Material is environmentally friendly, halogen-free, non-toxic, and tasteless, does not contain plastic softeners, has good shock absorption and anti-slip wear resistance, has good UV resistance and chemical resistance. Long-term use temperature of -60 degrees to 135 degrees
3.2: TPE (TPR) is a rubber with high elasticity, high strength, high resilience, and injection molding characteristics. It is environmentally friendly, non-toxic and safe, has a wide range of hardness, excellent colorability, soft touch, weather resistance, fatigue resistance and temperature resistance, excellent processing performance, no need for vulcanization, can be recycled to reduce costs, can be secondary injection molding, coated and bonded with base materials such as PP, PE, PC, PS, ABS, etc., can also be molded alone and replace part of soft PVC silicone rubber.

 

3.3: Usage
Melting point temperature: 150℃
Barrel temperature: 175℃-240℃
Mold temperature: 20℃-50℃
3.4: Molding precautions: TPE material has good fluidity, avoid high-speed and high-pressure injection to prevent product flash.
Drying material: No need to bake material; if storage conditions are not good, dry it at 80℃ for 1 hour. Material recycling: 100% recyclable
3.5: Shutdown matters: When shutting down, shoot material in barrel clean, no need to use other materials for cleaning, and spray mold with anti-rust oil.
Uses:
Handlebars, diving equipment, breathing tubes, sports pads, toothbrush handles, cable jackets

 

PP-full name: Polypropylene
4.1: Material Introduction
PP material has good heat resistance and will not deform when heated to 150℃ without external force, so it can be boiled in water.
Mechanical properties of PP are lower than those of PE, such as tensile strength, yield strength, compressive strength, hardness and elasticity. PP resin is easy to burn when exposed to fire, so you should pay attention when using it.
Shrinkage rate: 12‰-25‰
4.2: Usage method
Melting point temperature: 175℃
Barrel temperature: 200℃-240℃
Mold temperature: 20℃-70℃
Drying material: No need to bake material; if storage conditions are not good, dry it at 80℃ for 1 hour.
Material recycling: 100% recyclable

 

4.3: Molding precautions: When using PP materials, pay attention to product shrinkage and deformation. Products produced cannot be squeezed after packaging. PP resin has good fluidity, and high speed and high pressure should be avoided during production
4.4: Stoppage matters: When stopping, shoot material in barrel clean, no need to use other materials for cleaning and spray mold with anti-rust oil.
4.5: Various household items, transparent pot covers, chemical delivery pipelines, chemical containers, medical supplies, stationery, toys, wire drawing, water cups, turnover boxes, pipes, hinges, etc.

 

PS--full name: Polystyrene
5.1: Material Introduction
PS resin has poor flexibility, brittle and hard texture, poor impact resistance, and makes a metal-like sound when knocked.
PS resin has good fluidity and small molding shrinkage, and is easy to manufacture products with complex shapes. PS resin is colorless and transparent, and its light transmittance is second only to plexiglass. (PMMA) PS resin has a very low water absorption rate, its shape and size change very little in a humid environment. PS resin has excellent electrical insulation and is an excellent high-frequency insulation material. Main disadvantage of PS resin is its brittleness. In order to improve its brittleness, adding a small amount of butadiene (butadiene has high toughness and low elasticity) can reduce its brittleness. This is called high-impact polystyrene. (HIPS) Shrinkage: 3‰-6‰

 

5.2: Usage method
Melting point temperature: 166℃
Barrel temperature: 200℃-230℃
Mold temperature: 15℃-50℃
Material drying: No need to dry material; if storage conditions are not good, it can be dried at 80℃ for 1 hour
Material recycling: 100% recyclable.
5.3: Molding note: PS material has good fluidity, avoid high-speed and high-pressure injection
5.4: Shutdown matters: When shutting down, directly shoot material in barrel clean, and no other washing materials are needed for cleaning. And spray mold with anti-rust oil.
5.5: Application: Mainly used as transparent materials, daily necessities decorative parts, high-frequency insulation parts, foam packaging materials, and building insulation materials.

 

PMMA is full name: Polymethylmethacrylate
6.1: Material introduction: The most prominent feature of PMMA is its high transparency, with a light transmittance of 92%-95%. Light transmittance of inorganic glass is only 88%. Main advantages of PMMA are low density, light weight and toughness, better tensile strength and bending strength than inorganic glass. Main disadvantage of PMMA is its low hardness and easy burning when exposed to fire. Shrinkage rate: 3‰-7‰
6.2: Usage method
Melting point temperature: 130℃
Barrel temperature: 190℃-250℃
Mold temperature: 40℃-80℃
Drying material: Dry at 80℃ for 4 hours, and water absorption rate reaches 1%.
Material recycling: Appropriate recycled materials can be added

 

6.3: Molding Note: PMMA resin should have a fast production cycle to ensure color of product. PMMA is mostly used to make transparent products. It is best to fix machine during production. PMMA material has poor fluidity, and mold glue port should be opened larger. PMMA products are brittle, water port needs to be cut off with electric hot shears, and cannot be directly broken by hand.
6.4: Stoppage matters: When stopping, all materials in screw should be ejected. If production is to be carried out next day, turn on 120℃ insulation. No other materials need to be passed through machine. Mold needs to be sprayed with anti-rust oil.
6.5: Application: Mainly used as transparent materials: such as instrument cases, lampshades, transparent roofs, wall panels, automotive machinery and architectural safety glass, decorative materials, medical equipment, etc.

 

ABS full name is: Acrylonitrile-Butadiene Styrene
7.1: Material Introduction ABS resin is a ternary copolymer, and proportion of three elements can be adjusted as needed. Acrylonitrile has high hardness, good heat resistance and corrosion resistance; butadiene has high toughness and low-temperature elasticity; styrene has good molding processability, coloring and rigidity. ABS resin has a very low water absorption rate and will burn when exposed to fire. ABS resin can be added with different additives as needed to make general-purpose, medium-impact, high-impact, low-temperature impact, flame-retardant, electroplating, transparent, self-extinguishing and other varieties of ABS. Important feature of ABS is that surface can be: electroplated, spray-painted, printed, vacuum coated, painted. Shrinkage rate: 4‰-7‰

 

7.2: Usage (ordinary ABS)
Melting point temperature: 110℃
Barrel temperature: 180℃-250℃
Mold temperature: 40℃-80℃
Drying material: Dry at 80℃ for 3 hours.
Material recycling: 30% recycled material can be added
7.3: Molding notes: No special molding requirements, can be set according to product needs
7.4: Stop matters: When shutting down, eject barrel material cleanly, no other washing material is required; and spray mold with anti-rust oil.
7.5: Application: It is widely used: daily necessities, toys, electronic appliances, stationery, sports goods, furniture, food packaging, auto parts, etc.

 

PA6-full name: Polyammide
8.1: Material Introduction
PA6 resin has high strength, low friction coefficient, good white lubricity, and can be used as friction material under no lubrication or less lubrication conditions. PA6 resin has high water absorption, and water absorption rate in 24 hours is 2%. It should be avoided in high temperature and high humidity environments. Shrinkage rate: 7‰-20‰ (normal) 3‰-8‰ (add 30% GF)
8.2: Usage method
Melting point temperature 220℃
Barrel temperature: 230℃-260℃
Mold temperature: 60℃-100℃
Drying material: Dry at 80℃ for 4 hours. If storage conditions are not good, temperature can be increased.
Material recovery: 10% recycled material can be added

 

8.3: Molding notes: PA6 material has great water absorption. When molding, you should first confirm that material is completely dry. At the same time, this material has good fluidity, so high-speed and high-pressure injection should be avoided. Mold using PA6 material should have a good exhaust system, because good fluidity of PA6 material can easily cause product to burn; PA6 material cools quickly, and using shooting platform to retreat during injection molding will help smooth progress of production.
8.4: Stoppage matters: Stopping means that material in barrel is injected cleanly, and PP/PE material is used to pass machine: Tip: Products molded with PA6 material are too brittle and can be improved by soaking in water, boiling water, or adding vinegar when boiling water
8.5: Application: Wear-resistant parts, transmission parts such as bearings, gears, worm gears, pump impellers, zippers, etc. (especially textile and food machinery); mechanical parts that bear a certain load: chemical containers, etc.

 

PA66-full name: Polyamide
9.1: Material Introduction
PA66 has good strength, low friction coefficient and good self-lubricating properties. PA66 resin has low heat resistance and high hygroscopicity, so avoid using it in high temperature and high humidity environments.
Shrinkage: 7%-20%. (Normal) 4%-7% (add 30% GF)
9.2: Usage
Melting point temperature 240℃
Barrel temperature: 260℃-290℃
Mold temperature: 60℃-100℃
Drying: Dry at 80℃~150℃ for 4 hours (if storage conditions are not good, temperature can be increased)
Material recycling: 10% recycled material can be added.

 

9.3: Molding Note: Since PA66 resin has good water absorption, make sure that material is fully dried before use. Since PA66 material has good fluidity, high-speed and high-pressure injection should be avoided when using it. Mold using PA66 material should have a good exhaust effect to avoid product burning. Using shooting platform to retreat during production will help smooth production.
9.4: Shutdown matters: When shutting down, shoot glue in barrel clean and wash machine with PP/PE.
Differences between PA6 and PA66: PA66 has better strength than PA6 and less water absorption than PA6. When using, barrel temperature of PA66 is higher than that of PA6. Tip: If brittleness of PA66 products is too large, it can be improved by soaking in water, boiling water or adding vinegar when boiling water.
9.5: Application: valve seat, oil pipeline, oil storage container, rope, cable tie, transmission belt, grinding wheel adhesive, battery box, insulated electrical parts, wire core, wire drawing, etc.

 

POM is full name of Polyacetal
10.1: Material Introduction
POM resin has a small water absorption rate, which is 2.2‰-2.5‰ within 24 hours. This material can be used in a humid environment. POM material products can be used in a 100℃ environment; POM resin has good electrical insulation properties, especially in a humid environment, its electrical insulation is relatively stable. POM resin has very good mechanical properties, its elasticity, fatigue strength, and impact toughness are all excellent. POM resin has characteristics of low friction coefficient and good self-lubrication. Disadvantages of POM resin are: poor weather resistance, easy aging, and flammable. Shrinkage rate: 18‰-30‰. Stop shrinking after 24 hours
10.2: Usage method
Melting point temperature: 175℃
Barrel temperature: 180℃-205℃Mold temperature: 40℃-120℃
Material drying: Dry at 100℃ for 4 hours
Material recycling: Generally, 100% recycled materials can be used for molding

 

10.3: Molding notes: POM resin has average fluidity. It is best to connect a mold temperature controller when using it to facilitate flow of materials. POM resin is easy to age. Cycle should be measured quickly during molding to prevent carbonization and decomposition of material to produce toxic gases. Molding speed when using POM resin should not be too fast. Pay special attention to glue feeding point. POM resin is easy to decompose at high temperatures. Downtime in gun barrel should not exceed 5 minutes. When using POM materials, pay attention to gun barrel temperature should be set within specification.
10.4: Stoppage matters: When stopping, material in gun barrel must be ejected clean in time and machine must be washed with machine materials. At the same time, mold surface should be cleaned and sprayed with anti-rust oil in time.
10.5: Safety Tips: Do not smell it when firing in air, as gas produced is harmful to human body. Open exhaust system in workshop during firing in air to ensure air circulation in workshop.
10.6: Application: Replace various metals to make general structural parts, resistant parts and parts that bear heavy loads such as bearings, gears, pump impellers, valves, pump bodies, pipes, pulleys, zippers, auto parts, relay switches; instrument housings, etc.

 

PC-full name: Polycarbonate
11.1: Material Introduction PC resin is light yellow transparent, its light transmittance is second only to PMMA and PS in plastics. PC resin has very low water absorption and can be used in humid environments. Mechanical properties of PC resin are similar to those of PA and POM, and its impact strength is the best among commonly used engineering plastics. Creep strength is also the highest among commonly used engineering plastics. PC resin has outstanding heat resistance and cold resistance, its use range is -60℃ to 120℃, and it burns slowly when exposed to fire. PC resin products have two obvious disadvantages: one is low fatigue strength, and the other is that products are easy to crack, shrinkage rate: 6‰-8‰
11.2: Usage method
Melting point temperature: 220℃
Barrel temperature: 250℃-290℃
Mold temperature: 80℃-110℃
Drying material: Dry at 120℃ for 3 hours
Material recycling: Up to 20% recycled material can be added

 

11.3: Molding Note: When using PC material, connecting a mold temperature controller will help molding. PC material has poor fluidity and will be injected at high speed and high pressure during production. PC material is mostly used to produce transparent products because it requires high temperature, so it is best to fix machine. And screw plasticization effect is required to be good. When using PC material, production cycle should be as fast as possible to ensure color of product and maintain fatigue strength
11.4: Stoppage matters: Immediately eject material in barrel when shutting down. If production is to be carried out next day, open barrel to keep temperature at 220℃ or close it. Screw can be cleaned with high-viscosity PP/PE material.
11.5: Application:
Mechanical parts that bear a certain load, such as bearings, gears, worm gears, etc.; widely used in manufacture of power tool housings, etc.: optical instruments and lighting devices; packaging materials for steamed and frozen foods, medical device components, building lighting panels, window glass, optical disks, electronic and electrical accessories, etc.

 

ABS+PC full name: Aerylonitrile-Butadiene-styrene/Polycarbonate
12.1: Material Introduction ABS/PC has common characteristics of ABS and PC.
Physical properties: impact resistance, high gloss, light resistance, electroplating, spraying, heat resistance, high bending strength.
Chemical properties: only limited hydrolysis resistance.
Shrinkage: 5‰-7‰
12.2: Usage method
Melting point temperature: 130℃
Barrel temperature: 250℃-270℃
Mold temperature: 70℃-90C
Drying: Dry at 80℃ for 4 hours.
Material recycling: 20% recycled material can be added

 

12.3: Molding Notes: When using this material, if appearance requirements are strict, you can choose mold temperature to make appearance more beautiful.
12.4: Stopping matters: When stopping, all screw lining materials are ejected, and other washing materials do not need to be passed through machine.
12.5: Application: protective glasses, instrument panels, hair dryers, lighting equipment, electrical parts

 

PBT-full name: Polybutyleneterephthalate
13.1: Material introduction
PBT resin has good high thermal stability, good stiffness and hardness, low water absorption, good stress crack resistance, excellent friction and wear resistance, good dimensional stability, non-toxic. PBT is a flame retardant material, which will extinguish itself after leaving flame. It burns brightly, with orange flames, thick smoke, and a desulfurized aromatic hydrocarbon smell.
Shrinkage: 14‰-20‰ 4‰-6‰ (add 30% GF)
13.2: Usage
Melting point temperature: 224℃
Barrel temperature: 240℃-260℃
Mold temperature: 60℃-80℃
Drying: Dry at 120℃ for 4 hours
Material recycling: 20% recycled material can be added

 

13.3: Molding notes: No special molding requirements
13.4: Stoppage matters: When stopping, material in screw should be ejected in time and rod should be cleaned with machine cleaning material. Spray anti-rust oil on mold
13.5: Application:
Glasses, instrument panels, hair dryers, lighting equipment, electrical parts

PPO-full name: Polyphenylene Oxide
14.1: Material introduction: It has high heat resistance, glass transition temperature of 211 degrees, melting point of 268 degrees, decomposition when heated to 330 degrees, the higher PPO content, the better heat resistance, heat deformation temperature can reach 190 degrees, good flame retardancy, self-extinguishing, and medium flammability after mixing with HIPS. It is light and non-toxic and can be used in food and pharmaceutical industries. It has poor light resistance and will change color when used in sun for a long time. PPO plastic is generally in the form of khaki powder. It has excellent comprehensive properties. The biggest feature is that it has excellent dimensional stability and outstanding electrical insulation under long-term load. It has a wide operating temperature range and can be used for a long time in the range of -127~121℃. It has excellent water resistance and steam resistance. Product has high tensile strength and impact strength. In addition, it has good wear resistance and electrical properties. Shrinkage rate: 2‰-3‰
14.2: Usage:
Melting point temperature: 260℃
Barrel temperature: 275℃-330℃
Mold temperature: 80℃-150℃
Drying material: Dry at 150℃ for 4 hours
Material recovery: 20% recycled material can be added
14.3: Molding note: When using this material, if appearance requirements are strict, you can choose mold temperature to make appearance more beautiful
14.4: Shutdown matters: When shutting down, material in screw should be ejected in time and screw should be cleaned with washing material, and mold should be sprayed with anti-rust oil
14.5: Uses:
Suitable for making heat-resistant parts, insulating parts, wear-resistant parts, transmission parts, medical and electronic parts, gears, fan blades, valves and other parts. It can replace stainless steel and can make wires and motors.