ASTM D4662-20 PDF
Name in English:
St ASTM D4662-20
Name in Russian:
Ст ASTM D4662-20
Original standard ASTM D4662-20 in PDF full version. Additional info + preview on request
Full title and description
Standard Test Methods for Polyurethane Raw Materials: Determination of Acid and Alkalinity Numbers of Polyols (ASTM D4662-20). This designation describes titrimetric and potentiometric procedures to quantify acidic and basic constituents in polyols and other materials soluble in a toluene–ethanol mixture; results are commonly used for quality control and as correction factors when calculating hydroxyl numbers.
Abstract
ASTM D4662-20 specifies laboratory test methods to determine the acid number and alkalinity number of polyester polyols and similar polyurethane raw materials that dissolve in toluene/ethyl alcohol. The methods use alcoholic KOH titration (with phenolphthalein endpoint) and allow potentiometric endpoints; results support batch-to-batch uniformity checks, specification testing, and research.
General information
- Status: Superseded — the D4662 method (2020 edition) has been revised and is shown as replaced by a later ASTM revision (D4662-25).
- Publication date: 2020 (designation D4662-20; approved mid‑2020).
- Publisher: ASTM International (original publisher of the D4662 series).
- ICS / categories: Plastics / polyurethane raw materials test methods (commonly catalogued under Book Volume 08.02 and D20 committee activity for polyurethanes).
- Edition / version: D4662-20 (2020 edition).
- Number of pages: 3 pages (short test-method standard).
Scope
These test methods measure the acidic and basic constituents in polyols and other materials of high acidity or alkalinity that are soluble in mixtures of toluene and ethyl alcohol. The procedures do not apply to polyether polyols; they are intended for use in quality control, specification testing and research for polyurethane raw materials. Safety and regulatory considerations are the responsibility of the user.
Key topics and requirements
- Measurement of acid number (mg KOH/g) by titration of samples dissolved in a toluene/ethanol solvent with alcoholic KOH (phenolphthalein endpoint or potentiometric endpoint).
- Determination of alkalinity number via back‑titration after acid addition when required.
- Applicability limited to materials soluble in the specified solvent system; not suitable for polyether polyols.
- Results used as correction factors in hydroxyl‑number calculations and for batch consistency/quality control of polyols.
- Optional potentiometric endpoint determination is described as an alternative to visual indicators for improved endpoint reproducibility.
Typical use and users
Primary users are analytical and quality‑control laboratories, polyurethane raw‑material manufacturers, R&D teams working on polyol formulations, and third‑party testing labs. Typical uses include incoming material QC, batch uniformity checks, specification compliance, and supporting hydroxyl‑value determinations for formulation and process control.
Related standards
Closely related ASTM test methods include hydroxyl‑number determination methods for polyols (for example ASTM D4274 and related D427x series), other D20 series test methods for polyol properties, and supplementary titration/procedure standards used in polyurethane raw material testing. These related standards are commonly used together when characterizing polyols for polyurethane production.
Keywords
acid number, alkalinity number, polyols, polyurethane raw materials, titration, phenolphthalein, potentiometric endpoint, toluene‑ethanol solvent, hydroxyl number correction, D4662-20.
FAQ
Q: What is this standard?
A: ASTM D4662-20 is a short set of laboratory test methods that define how to determine acid and alkalinity numbers of polyester polyols and similar polyurethane raw materials soluble in a toluene/ethanol mixture.
Q: What does it cover?
A: It covers titrimetric (and optional potentiometric) procedures to quantify acidic and basic constituents, calculation of acid and alkalinity numbers (expressed in mg KOH/g), and guidance on applicability (not for polyether polyols). Results are intended for QC, specifications and research.
Q: Who typically uses it?
A: Chemical laboratories, polyurethane raw‑material producers, formulation and R&D chemists, and independent test labs performing incoming inspection and product quality validation.
Q: Is it current or superseded?
A: The 2020 edition (D4662-20) has been revised by a later ASTM revision (D4662-25); the 2020 text remains useful for historical reference and labs that reference that edition, but users requiring the latest, committee‑approved procedure should consult the newer D4662 revision. Confirm the required edition with contract specifications or regulatory documents.
Q: Is it part of a series?
A: Yes — D4662 is part of the ASTM D20 committee's body of test methods for polyurethane raw materials (Book Volume 08.02). It is typically used in conjunction with other D20 test methods such as hydroxyl‑number methods (e.g., ASTM D4274) and other polyol characterization standards.
Q: What are the key keywords?
A: acid number, alkalinity number, polyol, titration, potentiometric endpoint, toluene‑ethanol, hydroxyl correction factor, polyurethane raw materials.