ASTM D332-87(2020)

Standard Test Method for Relative Tinting Strength of White Pigments by Visual Observation

SIGNIFICANCE AND USE
4.1 This test method is used as a referee method and for quality control. The vehicle (oil) for preparing the dispersions and the tinting pigment (ultramarine blue) are specified but other vehicles and tinting pigments can be used. Any such changes in the test method must be agreed upon between the purchaser and the seller.  
4.2 The results obtained with a muller do not necessarily agree with an industrial situation where different dispersing conditions exist. However, dispersing with a muller is a fast and relatively inexpensive way of testing tinting strength for routine quality control.
SCOPE
1.1 This test method describes the procedure for determining the relative tinting strength of white pigments by visual assessment of blue tints.  
1.2 This test method is applicable only for comparing the test pigment with a reference standard of the same type and grade.  
Note 1: Test Method D2745 describes a procedure for instrumental evaluation of black tinted samples.  
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.4 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.  
1.5 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-2020
• ICS: 87.060.10 - Pigments and extenders
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.26 - Optical Properties

Relations

• Replaces: ASTM D332-87(2015) - Standard Test Method for Relative Tinting Strength of White Pigments by Visual Observation
• Effective Date: 01-Jun-2020
• Refers: ASTM D2745-00(2008) - Standard Test Method for Relative Tinting Strength of White Pigments by Reflectance Measurements
• Effective Date: 01-Feb-2008
• Refers: ASTM D2745-93 - Standard Test Method for Relative Tinting Strength of White Pigments by Reflectance Measurements
• Effective Date: 10-Nov-2000
• Refers: ASTM D2745-00 - Standard Test Method for Relative Tinting Strength of White Pigments by Reflectance Measurements
• Effective Date: 10-Nov-2000
• Refers: ASTM D262-81(1999) - Standard Specification for Ultramarine Blue Pigment (Withdrawn 2005)
• Effective Date: 10-Jul-1999
• Referred By: ASTM D2745-00(2023) - Standard Test Method for Relative Tinting Strength of White Pigments by Reflectance Measurements
• Effective Date: 01-Jun-2020
• Referred By: ASTM D7540-09(2019) - Standard Practice for Dispersion of Chromatic Pigments with a Mechanical Muller
• Effective Date: 01-Jun-2020
• Referred By: ASTM D79-86(2020) - Standard Specification for Zinc Oxide Pigments
• Effective Date: 01-Jun-2020

Overview

ASTM D332-87(2020), titled Standard Test Method for Relative Tinting Strength of White Pigments by Visual Observation, is a widely-recognized method developed by ASTM International. This standard specifies the procedures for determining the relative tinting strength of white pigments-such as titanium dioxide, zinc oxide, and white lead-by visually evaluating blue tints obtained by mixing each pigment with a reference blue pigment and vehicle (typically oil). The method primarily supports quality control and referee testing in the manufacture and use of white pigments in paints, coatings, plastics, and related industries.

The test involves dispersing both the test and reference white pigments in oil with a specified ultramarine blue pigment using a hand or automatic muller, and then visually comparing the tint strength. This standard ensures impartial and repeatable measurement, supporting product consistency and compliance with industry requirements.

Key Topics

• Visual Tint Strength Assessment: This method describes how to determine the tinting strength of white pigments by visually comparing the lightness of blue-tinted mixtures with a standard reference pigment.
• Quality Control: Widely used as a control tool in manufacturing to verify the consistency and performance of white pigments in production batches.
• Referee Method: ASTM D332 serves as a referee or arbitration standard, particularly in contractual situations between pigment suppliers and purchasers.
• Specified and Alternative Materials: The procedure calls for ultramarine blue as a tinting pigment and linseed oil as the vehicle, but allows other combinations if agreed by the relevant parties.
• Testing Apparatus: Use of calibrated balances, glass hand mullers or automatic mullers, spatulas, scrapers, and test panels is required.
• Comparison Scope: The method is explicitly designed for comparing a test pigment sample with a reference standard of the same type and grade.
• Measurement Units: Results are reported in SI units, supporting international communication and compliance.
• Safety Considerations: It is imperative that users follow appropriate safety, health, and environmental practices as required for handling chemicals and equipment.

Applications

• Pigment Manufacturing: Producers of white pigments use this standard to ensure each batch meets specified tinting strength requirements before shipping products to customers.
• Paint and Coatings: Paint manufacturers verify the consistency, opacity, and color strength of white paints and coatings, ensuring reliable performance in end-use applications.
• Plastics and Polymer Industries: Ensures that white pigments incorporated into plastics deliver consistent tinting and aesthetic properties.
• Contractual Testing: Serves as an agreed-upon method for resolving disputes or verifying quality between pigment buyers and suppliers.
• Research and Development: Provides a baseline for developing improvements in pigment formulations and dispersion techniques.

Related Standards

• ASTM D2745 - Standard Test Method for Relative Tinting Strength of White Pigments by Reflectance Measurements: Provides an instrumental, rather than visual, approach and is suitable for black-tinted samples.
• ASTM D262 - Specification for Ultramarine Blue Pigment (historically referenced in D332, though withdrawn).
• International Standards on Pigment Testing: ASTM D332 aligns with the principles established by the World Trade Organization’s TBT Committee, ensuring global harmonization and recognition.
• Other ASTM Paint and Pigment Standards: The D01 Committee on Paint and Related Coatings oversees synergistic standards for pigment and coating evaluation.

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Keywords: ASTM D332, tinting strength, white pigments, visual observation, quality control, pigment testing, paints and coatings, ultramarine blue, hand muller, automatic muller, pigment standards.

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: D332 − 87 (Reapproved 2020)
Standard Test Method for
Relative Tinting Strength of White Pigments by Visual
Observation
This standard is issued under the fixed designation D332; 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.
1. Scope 3. Summary of Test Method
1.1 This test method describes the procedure for determin- 3.1 Specified amounts of white pigment and blue tinting
ing the relative tinting strength of white pigments by visual pigment are dispersed together in oil using a glass hand muller
assessment of blue tints. or an automatic muller. Both the test and standard pigments are
treated identically. The pastes are drawn-down together on a
1.2 This test method is applicable only for comparing the
panel and visually assessed for tinting strength. To obtain a
test pigment with a reference standard of the same type and
numerical rating of tinting strength, dispersions with the
grade.
standard white pigment and more or less of the tinting pigment
NOTE 1—Test Method D2745 describes a procedure for instrumental
are made until the lightness of the test pigment paste is
evaluation of black tinted samples.
matched.The weight of the tinting pigment is used to calculate
1.3 The values stated in SI units are to be regarded as the
relative tinting strength.
standard. The values given in parentheses are for information
4. Significance and Use
only.
4.1 This test method is used as a referee method and for
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the quality control. The vehicle (oil) for preparing the dispersions
and the tinting pigment (ultramarine blue) are specified but
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- other vehicles and tinting pigments can be used. Any such
changes in the test method must be agreed upon between the
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor- purchaser and the seller.
dance with internationally recognized principles on standard-
4.2 The results obtained with a muller do not necessarily
ization established in the Decision on Principles for the
agree with an industrial situation where different dispersing
Development of International Standards, Guides and Recom-
conditions exist. However, dispersing with a muller is a fast
mendations issued by the World Trade Organization Technical
and relatively inexpensive way of testing tinting strength for
Barriers to Trade (TBT) Committee.
routine quality control.
2. Referenced Documents
5. Apparatus
2.1 ASTM Standards:
5.1 Balance, laboratory-type, sensitive to 0.1 mg, equipped
D262 Specification for Ultramarine Blue Pigment (With-
with a counter-balanced watch glass.
drawn 2005)
5.2 Buret, 1-mL capacity, stopcock controlled, graduated in
D2745 Test Method for Relative Tinting Strength of White
0.1-mLdivisions, or other suitable dispensing apparatus with a
Pigments by Reflectance Measurements
delivery accurate to 0.05 mL.
5.3 GlassHandMuller—Aweighted glass hand muller with
This test method is under the jurisdiction of ASTM Committee D01 on Paint
beveled edge having a total weight of 6.8 kg (15 lb) and a
and Related Coatings, Materials, andApplications and is the direct responsibility of
grinding face of from 70 to 75 mm (2 ⁄4 to 3 in.) in diameter.
Subcommittee D01.26 on Optical Properties.
Thefaceshallbefreeofblowholesandotherimperfectionsand
Current edition approved June 1, 2020. Published June 2020. Originally
approved in 1931. Last previous edition approved in 2015 as D332 – 87 (2015).
keptroughenedbylightlygrindingwithNo.303opticalemery,
DOI: 10.1520/D0332-87R20.
or its equivalent, and turpentine.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
5.4 Rubbing Surface—A ground glass plate, at least 355 by
Standards volume information, refer to the standard’s Document Summary page on
510 mm (14 by 20 in.), the surface of which is kept roughened
the ASTM website.
by lightly grinding with No. 303 optical emery, or its
The last approved version of this historical standard is referenced on
www.astm.org. equivalent, and turpentine.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D332 − 87 (2020)
TABLE 1 Quantities of Materials for Tinting Strength Tests
spatula by scraping the face of the muller and gathering the
Weight of paste on the slab into a mound. Repeat until the paste has been
Weight of
Ultramarine Amount of
given 100 rubs.
Pigment Type Pigment,
Blue Tinting Oil, mL
g
Pigment, g
NOTE 2—Where the resulting paste is too fluid or too thick for mulling,
White Lead 2 0.2 0.5
adjust the quantity of oil to give a workable paste and prepare a new paste,
Zinc oxide 2 0.2 0.7
mulling as before. Report the amount of oil used.
Zinc oxide, leaded 2 0.2 0.5
Titanium dioxide
7.2 Work2gofthe test pigment in exactly the same manner
(anatase) 2 0.4 1.0
as prescribed in 7.1 for the standard, using the same amount of
(rutile) 2 0.4 0.9
tinting material and oil.
7.3 Spread the paste of the standard and test pigments in
parallel contiguous rectangular areas on the panel, each about
5.5 Automatic Muller, automatic, equipped with a weight
25 mm (1 in.) wide and 50 mm (2 in.) long. Use the scraper to
that exerts a permanent 50-lbf (220-N) force and an additional
smooththesurfaceofthepastes(herecalled“draw-downs”)by
weightexertinga50-lbfmakingatotalof100-lbf(445-N).The
drawing the scraper lightly over the paste
...