TOP 10 Common Thermoplastics

Plastic Material Selection Guide

Plastic Injection Molding Material Selection Guide: Performance, Cost, and Applications of Ten Common Thermoplastics

☉ Material selection directly affects product strength, appearance, dimensional stability, molding cycle, and unit cost.

☉ Resin should not be selected by material name or price alone. Operating temperature, load, chemical exposure, appearance, and production conditions must also be considered.

☉ This guide summarizes ten commonly used thermoplastics as a practical starting point for product development and early material review.

Define the Product Requirements Before Selecting a Resin

During early product development, one of the first questions is often, “Which plastic should we use?” In practice, there is rarely one correct answer. A change in operating temperature, load, appearance, dimensional tolerance, or cost target may lead to a different material choice.

Material selection should therefore be reviewed together with the part structure, mold design, and intended production conditions. Selecting a resin based on one high value in a property table may overlook other limitations. A high-strength material may have limited flow, while a heat-resistant grade may require a higher mold temperature or longer molding cycle.

This guide is intended to narrow the initial material range. It does not replace the supplier’s technical data sheet, regulatory documents, or actual mold trials. Final selection should always be based on the specified material grade.

Five Basic Areas to Review During Material Selection

Review Area	Questions to Confirm	Common Data or Reference	Common Mistake
Mechanical	Will the part experience tension, compression, bending, torsion, or impact?	Tensile strength, flexural modulus, and notched Izod impact	Reviewing tensile strength while overlooking impact and fatigue
Thermal	What are the continuous and short-term operating temperatures?	HDT, Vicat temperature, melting point, and glass-transition temperature	Checking melting point without reviewing heat resistance under load
Chemical	Will the part contact oils, alcohol, acids, alkalis, or detergents?	Chemical compatibility charts and actual immersion testing	Overlooking damage caused by cleaners, sunscreen, or lubricants
Optical and Environmental	Does the product require transparency, outdoor weatherability, or UV resistance?	Light transmission, haze, weathering tests, and yellowing index	Reviewing initial clarity without considering long-term yellowing
Total Cost	What are the molding and tooling costs in addition to resin price?	Resin price, cycle time, yield, tooling, and secondary processing	Selecting a cheaper resin that increases cycle time or reject rate

Ten Common Thermoplastics

ABS injection-molded automotive air-conditioning component

01｜ABS

Acrylonitrile Butadiene Styrene

ABS provides a useful balance of impact resistance, processability, and molded appearance. It is widely used for housings, panels, and general mechanical components.

Main characteristics: Easy to injection mold and suitable for painting, printing, or plating with the correct grade.
Points to review: Heat and weather resistance vary by grade. Outdoor applications should use a suitable UV-resistant formulation.
Common applications: Automotive control panels, appliance housings, controllers, and consumer electronics.

View ABS Production Examples

PA nylon automotive intake manifold component

02｜PA

PA6, PA66, and Other Nylon Grades

PA offers good strength, wear resistance, and fatigue performance. Glass-fiber reinforcement can be used when higher stiffness and structural support are required.

Main characteristics: Suitable for structural components, fasteners, gear housings, and load-bearing parts.
Points to review: Many PA grades absorb moisture, which may affect dimensions and mechanical properties.
Common applications: Automotive intake components, power-tool housings, and sports-equipment fasteners.

View PA Nylon Production Examples

HDPE injection-molded plastic bottle cap

03｜HDPE

High-Density Polyethylene

HDPE has a low density and good resistance to many chemicals. Compared with LDPE, it provides higher rigidity and is widely used for containers, piping, and general chemical-resistant parts.

Main characteristics: Water resistant, chemically stable, and suitable for volume production.
Points to review: Molding shrinkage can be relatively high and should be considered during mold and dimensional planning.
Common applications: Caps, detergent containers, bins, agricultural piping, and filter components.

View HDPE Production Examples

04｜LDPE

Low-Density Polyethylene

LDPE is softer and more flexible than HDPE. It is commonly used where elongation, flexibility, and water resistance are more important than structural rigidity.

Main characteristics: Flexible, water resistant, and suitable for low-temperature use.
Points to review: Rigidity and heat resistance are limited, making it unsuitable for high structural loads.
Common applications: Films, flexible coverings, tubing, and low-load filter components.

View LDPE and HDPE Production Examples

05｜PC

Polycarbonate

PC combines transparency with high impact resistance and is commonly used for protective transparent parts, automotive lighting, and strong exterior housings.

Main characteristics: Transparent, tough, and available in grades with useful heat resistance.
Points to review: Proper drying and controlled molding conditions are important. Chemical stress cracking must also be considered.
Common applications: Automotive lenses, protective covers, helmet shells, and electronic equipment housings.

View PC Production Examples

POM polyoxymethylene injection-molded gear set

06｜POM

Polyoxymethylene／Acetal

POM provides low friction, wear resistance, and good dimensional stability. It is often used for gears, sliding parts, and mechanical components requiring accurate fit.

Main characteristics: Smooth sliding behavior, good stiffness, and suitability for repeated movement.
Points to review: Melt residence time and processing temperature must be controlled to avoid material degradation.
Common applications: Gears, bushings, slide rails, lock components, and curtain transmission parts.

View POM Production Examples

PMMA acrylic automotive tail-lamp component

07｜PMMA

Polymethyl Methacrylate／Acrylic

PMMA is mainly selected for optical clarity, gloss, and weatherability. It is suitable for transparent exterior parts, lamp covers, and display components.

Main characteristics: Good clarity, high surface gloss, and useful outdoor appearance retention.
Points to review: Impact resistance is generally lower than PC, so sharp corners and stress concentration should be avoided.
Common applications: Automotive tail lamps, transparent windows, lamp covers, displays, and optical appearance parts.

View PMMA Production Examples

08｜TPU

Thermoplastic Polyurethane

TPU combines elasticity, wear resistance, and tear resistance. It is commonly used for products requiring flexibility, soft touch, and durability.

Main characteristics: Available in a broad hardness range for flexible structures and elastic coverings.
Points to review: Many TPU grades absorb moisture and require appropriate drying before molding.
Common applications: Protective phone cases, watch straps, footwear components, rollers, and flexible wear parts.

09｜TPE／TPR

Thermoplastic Elastomer

TPE and TPR provide a rubber-like feel while using thermoplastic processing methods. They are often used for grips, anti-slip surfaces, and overmolding.

Main characteristics: Soft, flexible, and suitable for two-shot molding or overmolding.
Points to review: Adhesion to the substrate depends on the selected grade and should be verified through testing.
Common applications: Tool grips, cable coverings, seals, and children’s products.

Read the Overmolding Guide

10｜PP

Polypropylene

PP has a low density, good chemical resistance, and useful living-hinge performance. It is commonly selected for containers and high-volume molded parts.

Main characteristics: Lightweight, chemically resistant, and generally cost-effective to process.
Points to review: Molding shrinkage is relatively high, requiring careful mold and process control for appearance and dimensional accuracy.
Common applications: Food containers, living-hinge lids, automotive interior clips, and medical-related containers.

View PP Production Examples

Representative Thermoplastic Property Comparison

The values below are retained as representative ranges for preliminary comparison. Actual properties vary according to material grade, fillers, additives, testing standards, and specimen conditions.

#	Material	Density (g/cm³)	Melting or Processing Range (°C)	HDT @ 0.45 MPa (°C)	Tensile Strength (MPa)	Flexural Modulus (MPa)	Notched Izod (J/m)	Molding Shrinkage (%)
1	ABS	1.04	210–250	88–100	40–45	2,000–2,400	180–220	0.4–0.7
2	PA6	1.13	215–225	75–95	60–80	2,700–3,000	70–100	1.0–1.5
3	HDPE	0.95	125–135	75–85	26–33	900–1,200	50–70	1.5–4.0
4	LDPE	0.92	110–115	45–60	8–11	200–300	NB	1.5–4.0
5	PC	1.20	260–310	125–140	60–70	2,100–2,400	600–850	0.5–0.7
6	POM	1.41	165–175	100–120	60–75	2,800–3,200	90–110	1.5–2.0
7	PMMA	1.18	180–200	95–105	60–70	2,400–3,300	15–25	0.2–0.8
8	TPU	1.18	Grade dependent	45–90	30–50	25–70	700–900	1.0–2.0
9	TPE／TPR	0.90–1.25	Grade dependent	60–120	2–15	5–25	200–1,000+	1.0–2.5
10	PP	0.90	160–170	95–105	32–40	1,300–1,600	25–60	1.5–2.5

Data note: These values represent general-purpose or unfilled materials. Glass-fiber-reinforced, mineral-filled, flame-retardant, weather-resistant, food-contact, and medical grades may have different properties. Final selection should be based on the supplier’s TDS and applicable regulatory documents.

Quick Application Guide

Product Requirement	Material to Review First	Main Reason
Transparency and high impact resistance	PC	Provides a practical balance of clarity and impact toughness
Low-friction gears and sliding parts	POM	Low friction, wear resistance, and dimensional stability
Living hinges and high-volume containers	PP	Balances toughness, chemical resistance, and production cost
Outdoor transparent appearance parts	PMMA／Weatherable PC	Selection depends on clarity, impact, and weathering requirements
Soft-touch and overmolded parts	TPE／TPU	Flexible materials with substrate-specific bonding grades

A Practical Three-Step Material Selection Process

1 Define Product Requirements

Confirm strength, clarity, stiffness, friction, flame resistance, and weathering targets.

2 Review the Service Environment

List continuous temperature, chemicals, UV exposure, load, wear, and expected service life.

3 Calculate Total Cost

Review resin price, cycle time, yield, tooling, secondary processing, and quality risk together.

Clear＋Impact Resistant PC

Low Friction＋Precision Fit POM

Living Hinge＋Chemical Resistance＋Cost Control PP

Material Names Are Only the Starting Point

One resin family may include dozens of grades with different flow characteristics, heat resistance, flame ratings, glass-fiber content, weatherability, transparency, and regulatory status. Specifying “ABS” or “PC” is therefore only the first step.

Before mold design begins, the project should confirm the exact material grade, molding shrinkage, drying requirements, mold temperature, and product-use conditions. Food-contact, medical, flame-retardant, and outdoor applications also require the relevant regulatory and test documentation.

Frequently Asked Questions

Start by confirming the load, continuous operating temperature, chemical exposure, appearance requirements, dimensional tolerance, and cost target. These conditions help narrow the suitable material range.

No. The same resin family may include general-purpose, heat-resistant, flame-retardant, glass-fiber-reinforced, weather-resistant, and food-contact grades. Their properties, shrinkage, and processing conditions may differ.

Not necessarily. Flow behavior, molding cycle, yield, mold temperature, drying requirements, and secondary processing all affect total cost. A cheaper resin may increase overall cost if it causes longer cycles or more rejects.

Online tables are useful for preliminary comparison. Final design should use the supplier’s TDS for the specified grade and should confirm test methods, material condition, filler content, and actual service requirements.

Yes. Material data provides a design reference, but the actual result also depends on wall thickness, gate position, flow length, cooling, mold structure, and molding parameters. A trial is needed to verify dimensions, appearance, and process stability.

Plastic Material Review and Injection Molding Development

For projects involving strength, heat resistance, transparency, wear resistance, flame ratings, or production cost , our team can review the material direction, part structure, mold design, and molding conditions before the final material is confirmed through a mold trial.

2025-07-31