PP Flat washer
PP Flat Washer is a common, non-metallic fastener component made from Polypropylene (PP),Versatile, Economical, and Chemical-Resistant Spacing
M Size: M3-M30
peek plastic material: PP Polypropylene
product type: Washers
color: Natural/Black/Other Colors(Customizable)
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PP Flat washer Overview
PP Flat Washer is a common, non-metallic fastener component made from Polypropylene (PP), a commodity thermoplastic known for its excellent chemical resistance, low density (lightweight), and fatigue resistance.
Product Parameters
PP Flat Washers generally adhere to established metric standards for plain washers, such as ISO 7089 (Non-chamfered) or ISO 7090 (Chamfered), with dimensions defined by the inner diameter (ID), outer diameter (OD), and thickness (T).
| Nominal Size (Bolt d) | Inner Diameter (ID) | Outer Diameter (OD) | Thickness (T) |
| M3 | 3.2 mm | 7.0 mm | 0.5 mm |
| M4 | 4.3 mm | 9.0 mm | 0.8 mm |
| M5 | 5.3 mm | 10.0 mm | 1.0 mm |
| M6 | 6.4 mm | 12.0 mm | 1.6 mm |
| M8 | 8.4 mm | 16.0 mm | 1.6 mm |
| M10 | 10.5 mm | 20.0 mm | 2.0 mm |
| M12 | 13.0 mm | 24.0 mm | 2.5 mm |
| M16 | 17.0 mm | 30.0 mm | 3.0 mm |
Key Features
Polypropylene’s properties define the utility of the PP flat washer:
Excellent Chemical Resistance: PP is highly resistant to a vast range of acids, bases, salts, and organic solvents, offering corrosion resistance superior to that of stainless flat washer in many chemical solutions.
Low Density: It is one of the lightest thermoplastics, offering significant weight savings.
Good Fatigue Resistance: PP exhibits resilience against bending and flexing, making it suitable for assemblies subject to repetitive motion.
Cost-Effectiveness: PP is a commodity plastic, making its washers highly economical for high-volume manufacturing.
Electrical Insulation: It is an effective dielectric, preventing galvanic corrosion and short circuits between metal components.
Moisture Resistance: PP has extremely low water absorption, ensuring dimensional stability better than standard flat washer nylon.
Key Polypropylene (PP) Properties
Applications
PP Flat Washers are ubiquitous in consumer goods, chemical handling, and environments requiring moisture resistance.
Chemical and Laboratory Equipment: Used in tanks, valves, and fluid handling systems due to its high chemical inertness.
Outdoor and Marine Applications: Excellent resistance to moisture and salt, making it ideal for decking, boat fixtures, and general outdoor use where a flat rubber washer may degrade quickly.
Consumer Goods and Appliances: Used widely in non-critical assemblies due to its low cost and lightweight properties.
Plumbing: Employed in drain and pipe assemblies for its chemical resistance to household cleaners and its low water absorption.
General Isolation: Used as a non-conductive spacer to prevent contact between dissimilar metals, thereby stopping galvanic corrosion.
Advantages
| Category | ✅ Advantages (Pros) | ❌ Disadvantages (Cons) |
| Cost & Weight | Most Economical: Highly cost-effective for high-volume use. Extremely Lightweight. | Low Mechanical Strength: Low tensile strength and stiffness compared to high-performance plastics (like PEEK) or metal. |
| Protection | Excellent Chemical Resistance: Withstands most corrosive media better than many metal alloys. Excellent Moisture Resistance. | Temperature Limit: Lower service temperature (max. 100°C) than engineering plastics, limiting its use in hot environments. |
| Functionality | Good fatigue resistance. Reliable Electrical Isolation. | UV Degradation: Susceptible to UV degradation, requiring stabilizers for long-term outdoor use. |
| Comparison | Better chemical resistance than washer flat nylon. Preferred over flat rubber washer where stiffness is needed alongside chemical resistance. | Torque/Clamping: Low installation torque limit. Prone to creep (plastic deformation) under sustained high loads, making it unsuitable for use with flat lock washer designs. |
Packaging & Delivery
Standard packaging includes PE bag, foam cover, and one double-deck corrugated outer carton for safety during transit. Delivery time is 5-15 working days depending on the quantity.