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D1465-10 – Standard Test Method Technical Guide
🔬 Test Overview and Terminology
The ASTM D1465-10 standard, also recognized as TAPPI T 652, outlines the method for determining the blocking point and picking point of petroleum wax. These properties are critical in the paper-coating industry to assess the performance of waxed paper. The standard defines two key terms:
| 🔍 Term | 📏 Definition |
|---|---|
| Wax Blocking Point | The lowest temperature at which film disruption occurs across 50% of the waxed paper surface when test strips are separated. |
| Wax Picking Point | The temperature at which the first film disruption occurs on the waxed paper when test strips are separated. |
⚠️ Mercury Warning: This standard includes a warning about mercury, which is hazardous. Users must consult the Safety Data Sheet (SDS) and comply with local regulations regarding mercury-containing products.
⚙️ Test Procedure and Apparatus
The test involves coating paper specimens with the wax sample, folding them waxed sides together, and placing them on a blocking plate. The plate is heated at one end and cooled at the other to create a temperature gradient along its length. After conditioning, the specimens are separated and examined for film disruption.
Apparatus Requirements:
- Wax coating device (manual or machine-driven) capable of uniform coatings on paper strips at least 51 mm (2 in.) wide.
- Blocking plate with controlled heating and cooling to establish a temperature gradient.
- Thermometers conforming to ASTM Specification E1 for temperature measurement.
The test determines the points of initial film disruption (picking point) and where 50% of the specimen width is disrupted (blocking point). Corresponding temperatures on the blocking plate are reported.
📊 Key Measured Properties and Significance
The wax picking point and blocking point provide an approximate temperature range above which waxed surfaces in contact are likely to incur surface film injury. This is vital for preventing blocking in rolls of waxed paper, which can mar surfaces and destroy glossy finishes.
The standard references several ASTM methods to ensure consistency in testing:
| 📜 Standard | 📐 Description |
|---|---|
| D87 | Test Method for Melting Point of Petroleum Wax (Cooling Curve) |
| D938 | Test Method for Congealing Point of Petroleum Waxes, Including Petrolatum |
| D2423 | Test Method for Surface Wax on Waxed Paper or Paperboard |
| E1 | Specification for ASTM Liquid-in-Glass Thermometers |
💡 Tip: Use uniform coating weights to ensure reproducibility of results. The waxer should be calibrated according to the desired weight specifications.
❓ Frequently Asked Questions
🔍 What is the difference between the blocking point and picking point?
The picking point is where the first film disruption occurs, while the blocking point is where disruption covers 50% of the surface. Both indicate different stages of wax performance.
💡 Why is mercury mentioned in the standard?
Mercury has been used in some thermometers and equipment. Due to its hazards, the standard emphasizes caution and compliance with regulations.
⚡ What are the critical apparatus requirements?
Key apparatus includes a wax coating device for uniform coating on strips of at least 51 mm width, a blocking plate with temperature gradient, and thermometers per ASTM E1.
📌 How are the results reported?
The temperatures of the blocking plate corresponding to the picking point and 50% blocking point are reported as the wax picking point and blocking point or blocking range.