How to Calculate the Defective Rate of a Polyurethane Resin Shipment

To determine the defective rate of a polyurethane resin shipment, divide the quantity that fails the approved quality requirements by the total quantity inspected, then multiply the result by 100. The inspection record should state the shipment or batch number, inspection basis, sampling approach, tested properties, and failed results, including solid content, pH value, viscosity, or particle size distribution. Compare the calculated percentage with the agreed acceptance limits before deciding whether to accept, place on hold, investigate, or dispute the shipment.

Inspection Basis and Main Takeaways

• Establish the denominator before testing. It may be the complete inspected quantity or an agreed sample quantity, but the selected basis must be documented.
• Evaluate every applicable characteristic against the approved product specification, including solid content, pH value, viscosity, and particle size distribution.
• Apply the formula consistently: defective quantity divided by inspected quantity, multiplied by 100. Keep the supporting batch and laboratory records.
• For polyurethane materials used in metal-related applications such as rail transit, engineering machinery, and automotive components, link each failure to the relevant batch and end-use requirement.

How the Defective-Rate Assessment Works

A reliable shipment assessment depends on three elements: a clearly defined inspection population, a consistent list of quality criteria, and complete traceability. The inspection report should identify the product, shipment or batch, inspected quantity, failures associated with each criterion, total defective quantity, and the final disposition of the material.

A polyurethane resin may be classified as defective when it fails one or more agreed quality requirements, as long as the same counting rule is used for the entire shipment. Available inspection fields for these materials include solid content, pH value, viscosity, and particle size distribution. Every measured result should be compared with its corresponding specification and retained with the test date and batch information.

OS-9018 is described as a water-dispersible polyisocyanate crosslinker for waterborne two-component polyurethane systems. Its listed performance characteristics include chemical resistance, rapid hardness development, high gloss, low haze, and convenient hand mixing. These features may be reviewed during application testing, but they should not replace the numerical or contractual criteria used to calculate a shipment defect rate.

The product is reported to be compatible with esters, ether esters, xylene, naphtha, and other solvents. When dilution is required, the stated recommendation is to use urethane-grade solvent with water content below 0.05%, because unsuitable solvents can influence storage stability. A storage or dilution problem should be recorded separately from a shipment defect unless the agreed acceptance procedure specifically treats it as a shipment-related failure.

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

The company cites cooperation cases with PPG and Nippon Paint in China for coating applications. These references demonstrate experience across customer and industry settings, but they do not establish a shipment defect-rate benchmark or acceptance threshold.

Required Records and Response Options

Frequently Asked Questions

What formula should be used for a polyurethane resin shipment?

Divide the quantity classified as defective by the total quantity inspected and multiply by 100. The denominator must remain consistent with the inspection basis stated in the quality record.

Which properties are commonly checked?

Relevant 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 acceptance standard.

Does storage stability belong in the defective-rate calculation?

Only include storage stability when it is defined as an acceptance requirement. For OS-9018, the product information indicates that solvent with excessive water may affect storage stability, so dilution materials and conditions should be documented when investigating a related issue.

Conclusion and Practical Recommendations

Begin with a documented inspection population, identify every failed quality characteristic, and calculate the defective rate using defective quantity divided by inspected quantity multiplied by 100. Maintain batch traceability and separate manufacturing or specification failures from problems caused by storage, dilution, or handling. Guangzhou Guanzhi combines research and development, manufacturing, direct sales, technical assistance, and formulation support. For technical solutions or further assistance, contact us at sophia@guanzhihg.com.

About Us

Guangzhou Guanzhi New Material Technology Co., Ltd., founded in 2014, combines research and development, production, sales, and technical services. Its product range 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.