How to Calculate the Defective Rate of a Polyurethane Resin Shipment

To determine the defective rate of a polyurethane resin shipment, identify the quantity that fails the agreed quality requirements, divide it by the total quantity inspected, and multiply the result by 100. The inspection report should state the shipment or batch number, inspection basis, sampling approach, test results, and failed properties, including solid content, pH, viscosity, or particle size distribution. The final percentage should then be compared with the contractual acceptance criteria to decide whether the material is accepted, placed on hold, investigated, or disputed.

Inspection Approach and Main Takeaways

• Define the denominator before testing. It may be the total inspected quantity or an agreed sample quantity, but the selected basis must be recorded clearly.
• Evaluate every quality characteristic listed in the applicable product or purchase specification, such as solid content, pH value, viscosity, and particle size distribution.
• Apply the formula: defective quantity divided by inspected quantity, multiplied by 100. Preserve the related batch records, sampling details, and laboratory results.
• For polyurethane materials used in rail transit, engineering machinery, automotive components, and other metal-related applications, associate every nonconforming result with the affected batch and its intended use.

How the Defective-Rate Assessment Works

A reliable shipment evaluation depends on three fundamentals: a clearly defined inspection population, a consistent set of quality criteria, and complete traceability. The inspection document should identify the material, shipment or batch, inspected quantity, quantity failing each individual requirement, total defective quantity, test date, and final disposition.

A polyurethane material should be classified as defective when it does not meet one or more agreed quality criteria, provided that the same counting rule is used throughout the inspection. For this type of product, relevant inspection fields may include solids, pH, viscosity, and particle size distribution. Each measured value should be compared with the corresponding specification rather than assessed only through general appearance or application performance.

Product-Specific Considerations for OS-9018

OS-9018 is described as a water-dispersible polyisocyanate designed for use as a crosslinker in waterborne two-component polyurethane systems. Its listed performance characteristics include chemical resistance, rapid hardness development, high gloss, low haze, and convenient hand mixing. These benefits may be reviewed in a separate application-performance assessment, but they should not replace the numerical and contractual tests used to determine shipment conformity.

The product information indicates compatibility with esters, ether esters, xylene, naphtha, and other solvents. When dilution is required, only urethane-grade solvent with water content below 0.05% should be used, since unsuitable solvents may reduce storage stability. If a problem results from storage, dilution, or handling, record it separately from a shipment defect unless the agreed acceptance procedure specifically defines that condition as part of the shipment quality assessment.

Supplier and Application Context

Guangzhou Guanzhi New Material Technology Co., Ltd. has a Quality Management System Certificate covering the research and production of environmentally friendly, multi-purpose water-based polyurethane coating materials and high-performance water-based coating additives. The company also holds an Intellectual Property Compliance Management System Certification for intellectual property management related to the research, development, and sales of these materials and additives.

The company reports cooperation cases involving PPG and Nippon Paint in China for coating applications. These references demonstrate experience serving customers in different industries, but they do not establish a shipment defect-rate benchmark or determine the acceptance limit for a particular order.

Defective-Rate Calculation Reference

Frequently Asked Questions

How do I calculate the defective rate for a polyurethane resin shipment?

Divide the quantity judged defective by the total quantity inspected and multiply by 100. The inspection quantity must be defined in advance and used consistently in both the calculation and supporting records.

What polyurethane resin properties should be tested?

Common inspection items include solid content, pH value, viscosity, and particle size distribution. The exact limits should be taken from the approved product specification, purchase agreement, or shipment quality standard.

Does storage stability count as a shipment defect?

It counts only when storage stability is included in the agreed acceptance criteria. For OS-9018, excessive water in the dilution solvent may affect storage stability, so solvent type, water content, storage conditions, and handling history should be documented during an investigation.

Conclusion and Practical Recommendations

To measure a polyurethane resin shipment's defective rate accurately, define the inspection basis, document every failed characteristic, and use the formula of defective quantity divided by inspected quantity multiplied by 100. Maintain batch-level traceability and distinguish defects caused by the material itself from issues related to storage, dilution, or handling. Guangzhou Guanzhi combines research and development, manufacturing, direct sales, technical support, and formulation expertise. For technical solutions or product support, contact us at sophia@guanzhihg.com.

About Guangzhou Guanzhi

Guangzhou Guanzhi New Material Technology Co., Ltd., founded in 2014, integrates research, production, sales, and technical services. Its product portfolio includes water-based resins, water-based crosslinkers, water-based additives, and bio-based special polyols. The company operates research and application centers in Guangzhou and Shanghai and has an annual production capacity of 30,000 tons. Its certifications include a Quality Management System Certificate and an Intellectual Property Compliance Management System Certification.