ASTM D185-07(2023)

Standard Test Methods for Coarse Particles in Pigments

SIGNIFICANCE AND USE
3.1 In production of paints, smoothness of the paint film is of paramount importance. Agglomerates or coarse particles larger than 45 μm are difficult to disperse and may prevent obtaining a smooth film. These test methods are a valuable quality control test for grading raw materials.
SCOPE
1.1 These test methods cover the determination of the amount of coarse particles in dry pigments.  
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-May-2023
• ICS: 87.060.10 - Pigments and extenders
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.31 - Pigment Specifications

Relations

• Refers: ASTM E11-13 - Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves
• Effective Date: 01-Oct-2013
• Refers: ASTM E11-09e1 - Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves
• Effective Date: 01-May-2009
• Refers: ASTM E11-04 - Standard Specification for Wire Cloth and Sieves for Testing Purposes
• Effective Date: 01-May-2004
• Refers: ASTM E11-01 - Standard Specification for Wire Cloth and Sieves for Testing Purposes
• Effective Date: 10-May-2001
• Refers: ASTM E11-95 - Standard Specification for Wire Cloth and Sieves for Testing Purposes
• Effective Date: 10-May-2001

Overview

ASTM D185-07(2023) - Standard Test Methods for Coarse Particles in Pigments establishes procedures to determine the presence and quantity of coarse particles in dry pigments, particularly those larger than 45 micrometers (μm). This standard is essential for quality control in paint and coating manufacturing, ensuring the smoothness of finished paint films by identifying pigment agglomerates or undispersed coarse particles that could negatively impact film texture and performance.

The test methods described are integral for grading raw materials used in industrial coatings, paints, and other applications where pigment dispersibility and uniformity are critical.

Key Topics

• Coarse Particle Detection: The standard covers methodologies for isolating and quantifying coarse particles in pigment samples, focusing on particles larger than 45 μm.
• Quality Control in Pigment Production: Utilizes precise procedures to assure pigment quality, preventing defects in paint films due to undispersed, oversized particles.
• Sieve Analysis: Prescribes the use of a 45 μm (No. 325) test sieve conforming to ASTM E11, ensuring consistency and repeatability in testing.
• Sample Preparation and Handling: Details best practices for weighing, dispersing, sieving, and collecting retained material to avoid sample loss and ensure accurate results.
• Safety and Compliance: Reminds users to establish proper safety, health, and environmental protocols while adhering to relevant local regulatory requirements.

Applications

The procedures outlined in ASTM D185-07(2023) are widely applied in:

• Paint and Coating Manufacturing: Ensuring raw pigment quality to achieve smooth, defect-free paint films by detecting and grading out pigments with unacceptable levels of coarse particles.
• Pigment Supply Chain: Used by pigment producers and suppliers as a quality assurance tool, facilitating compliance with stringent customer specifications.
• Research and Development: Supports formulation scientists and chemists in evaluating new pigment sources or optimizing dispersion processes for innovative coatings and paints.
• Industrial and Commercial Quality Assurance: Serves as a reference method for inspection and certification labs assessing batch-to-batch pigment consistency.

By implementing this standard, manufacturers and suppliers can minimize product defects such as roughness, poor coverage, or compromised durability caused by coarse pigment agglomerates.

Related Standards

• ASTM E11 - Specification for Woven Wire Test Sieve Cloth and Test Sieves: Defines the requirements for sieves used in the coarse particle determination procedure.
• ASTM D01 Series: Encompasses additional test methods and standards for paints, pigments, and related coatings, materials, and applications.
• International Standards Relevant to Pigment Testing: The content of ASTM D185 aligns with global principles, including those set by the World Trade Organization Technical Barriers to Trade (TBT) Committee, facilitating international acceptance and harmonization.

Practical Value

Adhering to ASTM D185-07(2023) enables organizations to:

• Maintain consistent product quality and compliance with global standards
• Reduce the risk of product recalls or customer complaints related to surface finish
• Optimize raw material selection and manufacturing processes for higher efficiency and yield
• Enhance reputation in domestic and international pigment and paint markets

Keywords: coarse particles, pigments, agglomerates, quality control, sieve analysis, paint smoothness, ASTM D185, pigment grading, industrial coatings, test methods

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D185 − 07 (Reapproved 2023)
Standard Test Methods for
Coarse Particles in Pigments
This standard is issued under the fixed designation D185; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 45 μm sieve for comparison purposes should be retained in the
laboratory as a reference standard. Whenever a new sieve is
1.1 These test methods cover the determination of the
secured, a practical test of its accuracy should be made by
amount of coarse particles in dry pigments.
running on it and on the reference standard sieve a comparison
1.2 The values stated in SI units are to be regarded as the
test, using a pigment that has a considerable amount of coarse
standard. The values given in parentheses are for information
particles. A reserve stock of such a pigment should be kept for
only.
this purpose.
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5. Procedure for Insoluble Dry Pigments, Except Metallic
responsibility of the user of this standard to establish appro-
Aluminum and Bronze Powders
priate safety, health, and environmental practices and deter-
5.1 Weigh approximately 100 g of a pigment specimen to
mine the applicability of regulatory limitations prior to use.
the nearest 0.1 g on an analytical balance. Wet the sieve on both
1.4 This international standard was developed in accor-
sides with water and transfer the pigment to the sieve.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
5.2 Hold the sieve under a tap delivering about 300 mL to
Development of International Standards, Guides and Recom-
500 mL of the wash liquid (water) per minute. Slightly shake
mendations issued by the World Trade Organization Technical
the sieve and move the stream of water around on the pigment
Barriers to Trade (TBT) Committee.
in the sieve to get the pigment to pass through the sieve. Use
a soft camel-hair brush to help the pigment wet out and pass
2. Referenced Documents
through the sieve. If the sieve is held at a slight angle so that
2.1 ASTM Standards:
the pigment gradually collects at one edge during the washing
E11 Specification for Woven Wire Test Sieve Cloth and Test
process, and then rotated, the pigment may be brushed out
Sieves
rapidly, with no risk of clogging the sieve. Continue the water
rinsing and brushing until no more pigment is passing through
3. Significance and Use
the sieve. This can be checked by tilting the sieve and
3.1 In production of paints, smoothness of the paint film is
inspecting the water passing through for pigment.
of paramount importance. Agglomerates or coarse particles
larger than 45 μm are difficult to disperse and may prevent 5.3 When pigment is no longer passing through the sieve,
obtaining a smooth film. These test methods are a valuable adjust
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