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D1916-93 – Standard Test Method Technical Guide
📐 Test Overview and Scope
This standard, designated D1916-93 (Reapproved 1997), specifies the Standard Test Method for Penetration of Adhesives. It covers the determination of adhesive penetration under pressure in systems with at least one porous adherend. The method is particularly useful for starch and starch-base adhesives in the paper converting industry but may be adapted to other types.
The test helps in selecting and modifying adhesive systems to achieve maximum performance without excessive penetration into the substrate. Terminology is defined in D907, with “adhesive penetration” specifically meaning the entering of an adhesive into a porous adherend.
⚙️ Apparatus and Reagents
The penetration tester consists of a hammer (700 g, 25 mm diameter) that falls freely from 0.8 m onto an anvil (6 mm thick, 51 mm diameter). The hammer’s bottom end is cut at right angles within 0.051 mm tolerance and finished to 32 microfinish. A guiding tube ensures free fall without sideways movement.
| 🛠️ Component | 📏 Specification |
|---|---|
| Hammer diameter | 25 mm (1 in.) |
| Hammer weight | 700 g |
| Anvil thickness | 6 mm (1/4 in.) |
| Anvil diameter | 51 mm (2 in.) |
| Free fall distance | 0.8 m (31 in.) |
Other apparatus includes coarse filter paper disks (51 mm), 1-mL hypodermic syringe without needle, densitometer (e.g., MacBeth-Ansco Color Densitometer Model 12), and compensating planimeter (unit range 0.01 in² or 6.5 mm²).
The staining reagent varies by adhesive: for starch adhesives, an iodine solution with 2.0 g potassium iodide and 0.20 g iodine in 3 L distilled water; for basic pH adhesives, phenolphthalein or a suitable indicator.
📊 Test Procedure and Measured Properties
Procedure: Stack five filter paper disks on the anvil. Apply 0.1 mL of adhesive to the center of the hammer’s bottom end using the syringe. Invert the hammer if necessary and place it in the apparatus with the handle resting in the notch. Release the hammer to fall freely onto the anvil, striking it at right angles.
After impact, measure the penetration of the adhesive into the filter paper layers. Use a densitometer to assess the intensity of staining and a planimeter to quantify the area of penetration. This provides the key data for evaluating adhesive performance under standard impact conditions.
💡 Tip: Ensure the hammer end is clean and perfectly perpendicular to guarantee consistent impact and reproducible results.
⚠️ Safety Note: Staining reagents like iodine and phenolphthalein should be handled with care; use gloves and eye protection as needed.
❓ Frequently Asked Questions
🔍 What does D1916-93 measure?
It measures the penetration of adhesives into porous adherends under pressure, applicable to adhesives like those used in paper converting.
💡 How is the iodine staining solution prepared?
For starch adhesives, dissolve 2.0 g of potassium iodide and 0.20 g of iodine in 3 L of distilled water.
⚡ What are the key dimensions of the tester?
The hammer is 25 mm diameter, 700 g, falling 0.8 m onto an anvil 6 mm thick and 51 mm diameter.
📌 How many filter paper disks are used per test?
Five disks, each 51 mm in diameter, are stacked on the anvil for each test run.