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D6148-97 – Standard Test Method Technical Guide
📌 Scope and Terminology for Stickies Examination
ASTM D6148 – 97 (Reapproved 2007) establishes a standard practice applicable to virgin pulps and those derived from recovered materials used in the production of paper, paperboard, and other paper products (Section 1.1). The primary objective is to provide standardized laboratory procedures for separating stickies from pulp fibers, after which the separated fraction can be examined using qualitative or quantitative methods, or a combination of both (Section 1.2).
The standard specifically defines stickies as particulate, generally non-fibrous contaminants that adhere to themselves, other paper components, or machinery. These contaminants typically have a low specific gravity and include residual adhesives, coating residues, films, tapes, rubber-like particles, inks, and hydrolysis products of synthetic sizing materials (Section 3.2.1). Related terminology not specific to this standard is governed by ASTM D1968 and the Dictionary of Paper.
⚡ Regulatory and Safety Note: Users of this standard must establish appropriate safety, health, and environmental practices, as the standard does not purport to address all safety concerns (Section 1.3). Familiarity with referenced documents (ASTM D585, E122, and various TAPPI standards) is essential for proper implementation.
⚙️ Summary of the Separation Practice and Key Mechanisms
The core of the practice involves placing a slurry of mechanically disintegrated pulp fibers into a separatory device. This device brings the slurry into contact with a plate or screen of a defined area featuring openings of a specified number and size (Section 4.1).
The performance of the plate or screen is critical. It must achieve a separation efficiency sufficient to differentiate and discriminate between test materials known to contain different levels of stickies (Section 4.1.1). The standard allows for several mechanisms to recover the separated stickies from the screen:
- Recirculation: The slurry is recirculated in contact with the plate or screen within the separator device.
- Washing: Stickies remaining on the plate or screen are washed free using a supply of fresh water.
- Mechanical Removal: Stickies are carefully removed using tweezers or a similar tool. These mechanisms may also be used in combination (Section 4.1.2).
| 🟦 Separation Stage | 📏 Key Specification |
|---|---|
| Sample Preparation | Pulp slurry created, with mechanical disintegration if necessary |
| Separatory Media | Plate or screen with defined area and specified opening size/number |
| Efficiency Requirement | Must discriminate between materials with different stickies levels (4.1.1) |
| Recovery Methods | Recirculation, washing with fresh water, and/or mechanical removal (4.1.2) |
💡 Practical Consideration for Method Selection: The flexibility in recovery methods allows this practice to be adapted to various pulp types and stickies characteristics. For instance, sticky and soft contaminants may be best recovered via washing, while larger, discrete particles might be effectively captured and removed mechanically. The choice of screen size and separation efficiency should be aligned with the specific industrial process being simulated or the quality control objectives of the user.
📊 Key Referenced Documents for Compliance
Proper execution of this practice requires adherence to several ASTM and TAPPI standards. These documents provide the foundational methodologies for sampling, forming handsheets, and determining moisture content, all of which are critical to generating consistent and reproducible results in the separation and examination of stickies.
| 📐 Designation | 🎯 Title / Purpose |
|---|---|
| ASTM D585 | Practice for Sampling and Accepting a Single Lot of Paper, Paperboard, Fiberboard, and Related Product |
| ASTM D1968 | Terminology Relating to Paper and Paper Products |
| ASTM D2019 | Test Method for Dirt in Paper and Paperboard |
| ASTM E122 | Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or Process |
| TAPPI T 205 | Forming Handsheets for Physical Testing of Pulp |
| TAPPI T 412 | Moisture in Pulp, Paper and Paperboard |
| TAPPI UM 242 | Shive Content in Mechanical Pulp (Somerville Fractionator) |
❓ Frequently Asked Questions
🔍 What types of pulp are covered by ASTM D6148?
The practice covers a wide range of pulps, including virgin pulps and pulps derived from recovered materials used in the production of paper, paperboard, and related products (Section 1.1).
💡 How does the standard define “stickies”?
Stickies are defined as particulate, generally non-fibrous contaminants which adhere to themselves, paper components, or machinery. Examples include adhesives, coating residues, films, tapes, inks, and rubber-like particles (Section 3.2.1).