Performance and application of plastic raw materials for extruders

The main raw materials for extrusion of plastic products are various resins.Among them, polyethylene, polypropylene, and polyvinyl chloride resins are the most widely used. Here are some common types:

1.1 Performance of PVC

PVC is an amorphous plastic with poor thermal stability and is prone to thermal decomposition (improper melting temperature parameters can lead to material decomposition). PVC is difficult to burn (with good flame retardancy), has high viscosity, poor flowability, high strength, resistance to climate change, and excellent geometric stability. In practical use, PVC materials often contain stabilizers, lubricants, auxiliary processing agents, colorants, impact retardants, and other additives.

1.2 Application

Water supply pipelines, household pipelines, house wall panels, commercial machine shells, electronic product packaging, medical equipment, food packaging, etc.

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2.1 Performance of PE

PE is the most widely produced type of plastic, characterized by its softness, non toxicity, low cost, easy processing, good chemical resistance, resistance to corrosion, and difficulty in printing. PE is a typical crystalline polymer. It comes in various types, with commonly used ones being LDPE (low-density polyethylene) and HDPE (high-density polyethylene), which are semi transparent plastics.

The high crystallinity of HDPE results in its high density, tensile strength, high-temperature twisting temperature, viscosity, and chemical stability. It has stronger impermeability than LDPE. The impact resistance of PE-HD is relatively low. The characteristics are mainly controlled by density and molecular weight distribution.

The higher resistance to elongation, penetration, impact, and tear of LDPE (low-density polyethylene) makes LLDPE suitable for use as a film.

2.2 Application

LDPE has penetrated into most traditional markets of polyethylene, including films, molds, pipes, and wires and cables. Anti leakage film is a newly developed LDPE market. Plastic film, a large extruded sheet used as a landfill and waste pool liner to prevent leakage or pollution of surrounding areas.

HDPE application scope: refrigerator containers, storage containers, household kitchenware, sealing covers, etc.

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3.1 Performance of PP

PP is a crystalline polymer, and among commonly used plastics, PP is the lightest with a density of only 0.91g/cm3 (smaller than water). Among general plastics, PP has the best heat resistance, with a heat deformation temperature of 80-100 ℃, and can be boiled in boiling water. PP has good stress cracking resistance and high bending fatigue life. PP products are lightweight, have good toughness, and good chemical resistance. Disadvantages of PP: low dimensional accuracy, insufficient rigidity, poor weather resistance, and susceptibility to "copper damage". It has a phenomenon of post shrinkage, and after demolding, it is prone to aging, brittleness, and deformation. PP has always been the main raw material for manufacturing fibers due to its coloring ability, wear resistance, chemical resistance, and favorable economic conditions.

3.2 Application

The automotive industry (mainly using PP containing metal additives such as fenders, ventilation ducts, fans, etc.), equipment (dishwasher door liners, dryer ventilation ducts, washing machine frames and covers, refrigerator door liners, etc.), and daily consumer goods (lawn and gardening equipment such as lawn mowers and sprinklers). Injection molded products are the second largest market for PP homopolymers, including containers, seals, automotive applications, household goods, toys, and many other consumer and industrial end uses.

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4.1 Performance of PC

PC is an amorphous, odorless, non-toxic, highly transparent colorless or slightly yellow thermoplastic engineering plastic with excellent physical and mechanical properties, especially excellent impact resistance, high tensile strength, bending strength, and compression strength; Good toughness, heat and weather resistance, easy coloring, low water absorption. The hot deformation temperature of PC is 135-143 ℃, with low creep resistance and stable size; Has good heat resistance and low temperature resistance, stable mechanical properties, dimensional stability, electrical properties, and flame retardancy over a wide temperature range, and can be used for a long time at -60~120 ℃; No obvious melting point, in a molten state at 220-230 ℃; Stable to light, but not resistant to ultraviolet light, with good weather resistance; Resistant to oil, acid, strong alkali, oxidizing acids, as well as amines and ketones, soluble in chlorinated hydrocarbons and aromatic solvents, with antibacterial properties, flame retardant properties, and pollution resistance. Long term exposure to water can easily cause hydrolysis and cracking, but the disadvantage is poor fatigue strength, stress cracking, poor solvent resistance, poor flowability, and poor wear resistance. PC can be injection molded, extruded, molded, blow molded, printed, bonded, coated, and machined, with injection molding being the most important processing method.

4.2 Application

The three major application areas of PC are glass assembly industry, automotive industry, electronics and electrical industry, followed by industrial machinery parts, optical discs, civil equipment, computers and other office equipment, medical and health care, film, leisure and protective equipment, etc

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5.1 Performance of PA

PA is also a crystalline plastic with many varieties, commonly used in injection molding processes such as nylon 6, nylon 66, nylon 1010, nylon 610, etc. Nylon has toughness, wear resistance, and self-lubricating properties. Its main advantages include high organic mechanical strength, good toughness, fatigue resistance, smooth surface, high softening point, heat resistance, low friction coefficient, wear resistance, self-lubricating properties, shock absorption and noise reduction properties, oil resistance, weak acid resistance, alkali resistance and general solvent resistance, good electrical insulation, self extinguishing properties, non-toxic, odorless, and good weather resistance. The disadvantage is that it has high water absorption and poor dyeing ability, which affects the dimensional stability and electrical performance. Fiber reinforcement can reduce the water absorption rate, allowing it to work under high temperature and high humidity. The main disadvantages of PA are: easy to absorb water, strict requirements for injection molding technology, and poor dimensional stability.

5.2 Application

Application scope of PA12 polyamide 12 or nylon 12: water meters and other commercial equipment, cable sleeves, mechanical camshafts, sliding mechanisms, and bearings.

Application range of PA6 polyamide 6 or nylon 6: Due to its excellent mechanical strength and stiffness, it is widely used in structural components. Due to its excellent wear resistance, it is also used in the manufacture of bearings.

Application range of PA66 polyamide 66 or nylon 66: Compared with PA6, PA66 is more widely used in the automotive industry, instrument housings, and other products that require impact resistance and high strength.

6.1 Performance of PS

It is an amorphous polymer with good fluidity and low water absorption rate (less than 0.2%), making it an easy to shape and process transparent plastic. Its product has a light transmittance of 88-92%, strong coloring power, and high hardness. However, PS products are brittle, prone to internal stress cracking, and have poor heat resistance (60-80 ℃).

6.2 Application

Packaging products (containers, covers, bottles), disposable medical supplies, toys, cups, knives, magnetic tape reels, windproof windows, and many foam products. Product packaging, household items (tableware, trays, etc.), electrical (transparent containers, light source diffusers, insulating films, etc.).

7.1 Performance of ABS

ABS is synthesized from three chemical monomers: acrylonitrile, butadiene, and styrene. ABS is a light yellow granular or bead shaped opaque resin that is non-toxic, odorless, and has low water absorption. It has good comprehensive physical and mechanical properties, such as excellent electrical performance, wear resistance, dimensional stability, chemical resistance, and surface gloss, and is easy to process and shape. The disadvantages are weather resistance, poor heat resistance, and flammability. ABS material has strong processability, appearance characteristics, low creep resistance, excellent dimensional stability, and high impact strength.

7.2 Application

Cars (dashboard, tool compartment door, wheel cover, mirror box, etc.), refrigerators, high-strength tools (hair dryers, mixers, food processors, lawn mowers, etc.), telephone cases, typewriter keyboards, entertainment vehicles such as golf carts and jet sleds.

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8.1 Performance of PMMA

PMMA is an amorphous polymer, commonly known as organic glass. Excellent transparency, good heat resistance (hot deformation temperature of 98 ℃), and good impact resistance. Its product has moderate mechanical strength, low surface hardness, and is easily scratched by hard objects, leaving traces. Compared with PS, it is less prone to brittle cracking and has a specific gravity of 1.18g/cm3. PMMA has excellent optical properties and resistance to climate change. The transparency of white light is as high as 92%. PMMA products have very low birefringence, making them particularly suitable for making DVDs and other materials. PMMA exhibits room temperature creep characteristics. With the increase of load and time, stress cracking can occur.

8.2 Application

Automotive industry (signal light equipment, dashboard, etc.), pharmaceutical industry (blood storage containers, etc.), industrial applications (DVDs, light diffusers), daily consumer goods (beverage cups, stationery, etc.).

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The above is the relevant introduction about "understanding the performance and application of plastic raw materials for extruders", hoping to be useful to everyone. Hangzhou Polytech Plastic Machinery CO.,LTD is a professional manufacturer of plastic extrusion lines with a technical team of over 20 years of design experience. Welcome new and old customers to call and inquire.