I. Introduction & Quality Objectives
As testing personnel in the Quality Department of Linghua New Materials, our core mission is to ensure that every roll of TPU PPF base film leaving our factory is not just a conforming product, but a stable, reliable solution that exceeds customer expectations. This document aims to systematically define the key testing items and execution standards for PPF semi-finished products and, based on historical data and problem analysis, formulate forward-looking quality improvement plans to support the company’s strategic goal of “defining the benchmark for TPU film quality in China.”
We are committed to data-driven quality management to achieve:
- Zero Customer Complaints: Ensure products 100% meet key performance indicators.
- Zero Batch Variation: Control batch-to-batch fluctuations of key parameters within ±3%.
- Zero Risk Overflow: Intercept potential quality risks within the factory through preventive testing.
II. Core Testing Items and Execution Standard System
We have established a four-stage testing system from raw materials to finished products. All tests require traceable raw data recording and archiving.
Stage 1: Incoming Quality Control (IQC)
| Test Item | Test Standard | Control Limits & Frequency | Non-conformance Handling |
|---|---|---|---|
| Aliphatic TPU Resin YI Value | ASTM E313 / ISO 17223 | ≤1.5 (Typical), Mandatory per Batch | Reject, notify Purchasing Dept. |
| TPU Resin Melt Flow Index | ASTM D1238 (190°C, 2.16kg) | Within spec ±10%, Mandatory per Batch | Quarantine, request evaluation by Tech Dept. |
| Masterbatch Dispersion | Internal Pressed Plate Comparison | No color difference/specks vs. standard plate, Mandatory per Batch | Reject |
| Packaging & Contamination | Visual Inspection | Sealed, uncontaminated, clear labeling, Mandatory per Batch | Reject or accept after cleaning with concession |
Stage 2: In-Process Quality Control (IPQC) & Online Monitoring
| Test Item | Test Standard/Method | Control Limits & Frequency | Improvement Trigger Mechanism |
|---|---|---|---|
| Film Thickness Uniformity | Online Beta Gauge | Transverse ±3%, Longitudinal ±1.5%, 100% Continuous Monitoring | Auto-alarm and automatic die lip adjustment if OOS |
| Surface Corona Tension | Dyne Pen/Solution | ≥40 mN/m, Tested per Roll (Head/Tail) | Immediate line stop to check corona treater if <38 mN/m |
| Surface Defects (Gels, Streaks) | Online High-Def CCD Vision System | ≤3 pcs/㎡ allowed (φ≤0.1mm), 100% Monitoring | System auto-marks defect location and triggers alarm |
| Extrusion Melt Pressure/Temp. | Sensor Real-time Logging | Within range defined in《Process Work Instruction》, Continuous | Early warning to prevent degradation if trend is abnormal |
Stage 3: Final Quality Control (FQC)
This is the core basis for release. Mandatory for every production roll.
| Test Category | Test Item | Test Standard | Linghua Internal Control Standard (Grade A) | |
|---|---|---|---|---|
| Optical Properties | Haze | ASTM D1003 | ≤1.0% | |
| Transmittance | ASTM D1003 | ≥92% | ||
| Yellowness Index (YI) | ASTM E313 / D1925 | Initial YI ≤ 1.8, ΔYI (3000hrs QUV) ≤ 3.0 | ||
| Mechanical Properties | Tensile Strength | ASTM D412 | ≥25 MPa | |
| Elongation at Break | ASTM D412 | ≥450% | ||
| Tear Strength | ASTM D624 | ≥100 kN/m | ||
| Durability & Stability | Hydrolysis Resistance | ISO 1419 (70°C, 95%RH, 7 days) | Strength Retention ≥ 85%, No Visual Change | |
| Thermal Shrinkage | Internal Method (120°C, 15min) | MD/TD both ≤1.0% | ||
| Key Safety Item | Fogging Value | DIN 75201 (Gravimetric) | ≤ 2.0 mg | |
| Coating Compatibility | Coating Adhesion | ASTM D3359 (Cross-cut) | Class 0 (No peeling) |
Stage 4: Type Testing & Validation (Periodic/Customer Request)
- Accelerated Aging: SAE J2527 (QUV) or ASTM G155 (Xenon), performed quarterly or for new formulations.
- Chemical Resistance: SAE J1740, contact with engine oil, brake fluid, etc., tested quarterly.
- Full Spectrum Analysis: Use spectrophotometer to measure 380-780nm transmittance curve, ensuring no abnormal absorption peaks.
III. Common Quality Issue Improvement Plans Based on Test Data
When test data triggers a warning or non-conformance occurs, the Quality Department will jointly initiate the following root cause analysis and improvement process with Production and Technical departments:
| Common Quality Issue | Related Failed Test Items | Root Cause Analysis Direction | Quality Dept.-Led Improvement Actions |
|---|---|---|---|
| Haze/YI Exceeds Standard | Haze, YI, QUV Aging | 1. Poor raw material thermal stability 2. Processing temp too high causing degradation 3. Environmental or equipment contamination |
1. Initiate Material Traceability: Review all test reports for that batch of resin/masterbatch. 2. Audit Thermal History: Retrieve production logs (melt temp, pressure curve, screw speed). 3. Propose & Supervise ”Cleaning Week” activity for screw, die, and air ducts. |
| Coating Adhesion Failure | Dyne Value, Cross-cut Adhesion | 1. Insufficient or decayed corona treatment 2. Low-MW substance migration contaminating surface 3. Unsuitable surface microstructure |
1. Enforce Calibration: Require Equipment Dept. to calibrate corona treater power meter daily. 2. Add Monitoring Point: Add surface FTIR testing in FQC to monitor migration characteristic peaks. 3. Drive Process Trials: Collaborate with Tech Dept. to test adhesion under various corona settings, optimizing SOP. |
| High Fogging Value | Fogging Value (Gravimetric) | High content of small molecules (moisture, solvent, oligomers) | 1. Stricter Drying Verification: Perform quick moisture test (e.g., Karl Fischer) on dried pellets post-IQC. 2. Optimize Curing Process: Establish minimum curing time & temp standards for different thicknesses based on experimental data, and monitor compliance. |
| Thickness/Appearance Fluctuation | Online Thickness, CCD Detection | Process parameter fluctuation or unstable equipment condition | 1. Implement SPC (Statistical Process Control): Create X-R control charts for thickness data to detect abnormal trends early. 2. Establish Equipment Health Files: Correlate maintenance records of key equipment (die, chill roll) with product quality data. |
IV. Continuous Improvement of the Quality System
- Monthly Quality Meeting: Quality Department presents the《Monthly Quality Data Report》, focusing on TOP 3 issues, driving cross-departmental improvement projects.
- Test Method Upgrades: Continuously monitor updates to ASTM, ISO standards; review the effectiveness of internal test methods annually.
- Internalizing Customer Standards: Convert key customers’ specific requirements (e.g., requirements from an automaker’s TS16949 system) into internally tightened test items and incorporate them into the control plan.
- Lab Capability Building: Perform regular instrument calibration and personnel comparative testing to ensure the accuracy and consistency of test results.
Conclusion:
At Linghua New Materials, quality is not the final inspection but is integrated into every link of design, procurement, production, and service. This document is the foundation of our quality work and a dynamic, updated commitment. We will use rigorous testing as our ruler and continuous improvement as our spear, ensuring that “Made by Linghua” TPU PPF base film becomes the most stable and trustworthy choice in the global high-end PPF market.
Post time: Dec-23-2025