In the industrial manufacturing sector, Polyurethane (PU) has become the premier alternative to rubber, plastic, and even metal due to its exceptional abrasion resistance, tear strength, and wide range of adjustable hardness. However, because PU formulations are complex and processing techniques vary, procurement professionals often face dilemmas such as “qualified samples but unstable mass production” or “service life far below expectations”.
From a technical perspective, we reveal the four core dimensions for identifying high-quality polyurethane components.
Define the Chemical System: Polyester vs. Polyether
A foundational understanding of PU formulations is essential. By evaluating a supplier’s proposed solution—or whether they proactively inquire about your operating environment (exposure to water, oil, chemicals, or high-frequency friction)—you can gauge their technical expertise.
Polyester-based: Offers high mechanical strength, superior oil and solvent resistance, and extreme sliding abrasion resistance. It is ideal for seals, scrapers, or wear parts with rigorous physical requirements. Disadvantage: Poor hydrolysis resistance; it has strict humidity requirements for storage and use, making it best suited for applications with a service or shelf life of under one year. It also performs poorly in low temperatures.
Polyether-based: Features excellent low-temperature flexibility, hydrolysis resistance, fungus resistance, and high resilience. While it maintains good mechanical strength and abrasion resistance, it excels in underwater operations, cold storage, or high-frequency vibration damping.
Evaluate Processing Techniques: Cast vs. Injection Molding
The production process directly determines the component’s lifespan.
CPU (Cast Polyurethane): Best for applications requiring peak physical properties. It features a higher molecular weight, resulting in physical performance that typically far exceeds injection-molded products. It is ideal for low-to-medium volume orders or high-performance parts. Additionally, initial tooling costs are lower, making it perfect for the prototyping and R&D phases.
TPU (Thermoplastic Polyurethane/Injection): Suited for small, thin-walled parts required in massive quantities. While production efficiency is high and unit costs are low, the performance is significantly lower than cast versions. This is the choice for price-sensitive, high-volume projects where performance requirements are secondary.
Balancing Hardness and Tolerances
Polyurethane spans a vast hardness range, from Shore A10 to D85.
Hardness Selection: This must be based on design requirements and equipment performance. Factors such as impact resistance, rebound, compression set, and equipment stability must be balanced. A supplier’s ability to guide this selection is a key indicator of their professional capability.
Dimensional Precision: Since polyurethane is subject to thermal shrinkage, high-quality suppliers ensure dimensions through precise mold design and Post-Curing. Asking about the post-cure duration (typically 12–24 hours) is a critical way to distinguish professional manufacturers from “small workshops”.
Surface Quality and Internal Defect Detection
Appearance is more than aesthetics; it is a signal of structural integrity.
Bubbles & Impurities: Bubbles are categorized into “process bubbles” and “material defect bubbles”. Isolated process bubbles are often unavoidable and generally do not affect performance. However, dense micro-bubbles indicate material defects that will shorten product life and are unacceptable. Impurities represent poor quality control and are likewise unacceptable.
Bonding Strength: For metal-bonded parts (like polyurethane rollers), examine the metal surface sandblasting treatment and the performance of the adhesive agents used.
Procurement Checklist
Before placing a high-volume order, request the following data from your supplier:
Material Physical Property Datasheet: Including tensile strength, elongation at break, coefficient of friction, and low-temperature brittle point.
Hardness Test Report: Ensuring batch hardness tolerances are controlled within a specific ±3 Shore A range.
Environmental Simulation Tests: If used in specialized conditions, request oil resistance or hydrolysis experiments.
If you encounter challenges in selecting or sourcing custom polyurethane components, please contact Kubis Tech LTD (库毕斯). We are dedicated to providing you with professional solutions and services.
