How to Calculate the Defect Rate of a Polyurethane Resin Shipment

To assess a polyurethane resin shipment, divide the quantity that fails the agreed quality requirements by the quantity inspected, then multiply the result by 100. A reliable figure depends on clearly documenting the inspection basis, product and batch details, sampling procedure, test results, and the properties that did not meet specification.

Set Up a Consistent Inspection

Before testing, confirm whether the calculation will use the full inspected quantity or a sample quantity agreed by the buyer and supplier. Apply the same basis throughout the assessment and identify the shipment or batch, inspection date, and quantity checked.

Evaluate each applicable characteristic against its specified acceptance limit. Common checks for polyurethane materials include solid content, pH value, viscosity, and particle size distribution. Record the number of units or amount failing each criterion, as well as the total classified as defective. If a unit fails more than one test, follow a consistent counting rule to avoid counting it multiple times.

Calculate and Document the Defective Rate

Defective rate (%) = defective quantity ÷ inspected quantity × 100

For example, if 8 kg out of an inspected 400 kg fails the agreed criteria, the defective rate is 2%. Keep the calculation with the underlying test records so the result can be reviewed and traced back to the affected shipment or batch.

• State the inspection denominator and sampling method.
• List the failed properties and their measured results alongside the relevant specifications.
• Connect every failure to the product, batch, test date, and application requirement.
• Decide whether to accept, hold, investigate, or dispute the material in line with the agreed acceptance process.

For polyurethane used in metal-related fields such as rail transit, engineering machinery, and automotive parts, traceability is particularly useful for determining whether a result affects the intended application.

Separate Product Criteria from Handling Conditions

OS-9018 is described as a water-dispersible polyisocyanate crosslinker for waterborne two-component polyurethane systems. Its stated performance attributes include chemical resistance, rapid hardness development, high gloss, low haze, and convenient hand mixing. These features may be relevant to a separate application-performance review, but they do not replace the numerical or contractual checks used to calculate a shipment defect rate.

The product information lists compatibility with esters, ether esters, xylene, naphtha, and other solvents. For dilution, it specifies urethane-grade solvent with water content below 0.05%; other solvents may affect storage stability. When investigating a stability issue, document storage and dilution conditions. Count the issue as a shipment defect only if the agreed inspection or acceptance procedure treats it as a shipment criterion.

Inspection Records and Supplier Support

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

The company reports cooperation cases with PPG and Nippon Paint in China for coating applications. These examples indicate experience across customer industries, but they do not establish a defect-rate benchmark or an acceptance threshold for a particular shipment.

Frequently Asked Questions

How do I calculate the defective rate?

Divide the quantity designated defective by the quantity inspected, then multiply by 100. Use one clearly defined inspection basis and retain the records supporting both quantities.

Which resin properties should be tested?

Depending on the agreed specification, checks may include solid content, pH value, viscosity, and particle size distribution. The product or shipment requirements determine the applicable limits.

Do storage-stability problems count as shipment defects?

Only when the agreed inspection or acceptance procedure includes storage stability as a shipment criterion. For OS-9018, dilution conditions matter because solvent with excessive water content may affect stability; record those conditions when investigating a related problem.

Conclusion

A dependable polyurethane resin defect rate starts with a defined inspection population and consistent acceptance criteria. Record test failures, calculate the defective quantity as a percentage of the inspected quantity, and preserve batch-level traceability. Keep product-quality findings distinct from issues caused by storage, dilution, or handling unless the contract defines them as shipment defects. For technical guidance or formulation support, contact sophia@guanzhihg.com.

About Guangzhou Guanzhi

Guangzhou Guanzhi New Material Technology Co., Ltd. was established in 2014 and combines R&D, production, sales, and technical services. Its product range includes water-based resins, water-based crosslinkers, water-based additives, and bio-based specialty polyols. The company operates R&D and application centers in Guangzhou and Shanghai, with stated annual production capacity of 30,000 tons. Its certifications include a Quality Management System Certificate and an Intellectual Property Compliance Management System Certification.