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D3522-86 – Standard Test Method Technical Guide
📐 Scope and Terminology
ASTM D3522-86 (Reapproved 2007) specifies a test method for determining the weight of applied coating wax and impregnating (saturating) wax in corrugated board facing. This method is applicable to boards that have a coated surface and also contain wax saturation within the facing structure (Section 1.2). Key terminology includes “weight percent impregnating wax” defined as the weight of wax relative to the unwaxed facing at 23°C (73°F) and 50% relative humidity, and “weight of applied coating wax” defined as the weight per unit area, typically in g/m² or lb/1000 ft² (Sections 3.1.1, 3.1.2). The standard also references ASTM D585 for sampling, D3344 for total wax content, and D3521 for surface wax coating (Section 2.1).
⚠️ Users must establish appropriate safety and health practices before use. For specific hazard statements, refer to Section 7.1 of the standard (Section 1.3).
| 🟦 Parameter | 📏 Definition | 🎯 Unit |
|---|---|---|
| Weight Percent Impregnating Wax | Wax weight relative to unwaxed facing | % at 23°C, 50% RH |
| Weight of Applied Coating Wax | Wax per unit area on board surface | g/m² or lb/1000 ft² |
| Standard Test Conditions | Temperature and humidity for measurement | 23°C, 50% RH |
⚙️ Test Procedure and Layer Separation
The test method begins by peeling the coated facing from the corrugated medium. The facing is then split into two distinct layers: one bearing the coating on waxed fibers and one containing waxed fibers only (Section 4.1). These layers are extracted separately, collecting both fibers and wax, allowing calculation of the applied surface coating wax and the impregnating wax. For impregnating wax, the principal concern is the weight percent loading (pickup) relative to the paperboard weight, assuming uniform distribution. For coating wax, the focus is on weight per unit area, assuming most of the molten coating remains on the surface without undue migration into the fibrous structure (Sections 5.1.1, 5.1.2). Practical notes indicate that in curtain coating applications, up to about 10% of the coating may migrate into the fibers (Note 2).
💡 If the board has only coating wax with no internal impregnating wax, total coating wax may be determined by ASTM D3344. For surface wax alone, ASTM D3521 is an alternative (Note 1).
📊 Key Measured Properties
The primary measured properties are weight percent impregnating wax (loading) and weight of applied coating wax per unit area. These are critical for evaluating the moisture resistance of corrugated fiberboard containers, which is improved by wax treatment common in saturation and curtain coating or roll coating operations (Section 5.1). The test is conducted under standard conditions of 23°C and 50% relative humidity to ensure consistency. Note that this method does not directly measure weight of impregnating wax per unit area, as not all facing fibers are used in testing (Section 5.1.1). The functional performance of the board depends on the amount of wax in each operation, making this method useful for quality control and process evaluation.
| 🟦 Property | 📏 Measurement Focus | ⚡ Application |
|---|---|---|
| Impregnating Wax Loading | Weight percent relative to unwaxed facing | Evaluates saturation uniformity |
| Applied Coating Wax | Weight per unit area (g/m² or lb/1000 ft²) | Quantifies surface wax deposition |
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D3522-86? It determines the weight of applied coating wax and impregnating wax in corrugated board facing, especially for boards with both surface coating and internal saturation (Section 1.1).
💡 How is the test sample prepared? The coated facing is peeled from the medium and split into two layers: one with coating on waxed fibers and one with only waxed fibers, for separate extraction (Section 4.1).
⚡ What units are used for coating wax? The weight of applied coating wax is expressed in grams per square metre or pounds per thousand square feet of board (Section 3.1.2).
📌 Are there alternative test methods? Yes, ASTM D3521 for surface wax coating and D3344 for total wax content when no internal impregnating wax is present (Note 1).