ISO 3451-4:2024
Plastics — Determination of ash — Part 4: Polyamides

Standard No.

ISO 3451-4:2024

Release Date

2024

Published By

International Organization for Standardization (ISO)  IX  /  ISO

Latest

ISO 3451-4:2024

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Introduction

Analysis of the core content of the standard

ISO 3451-4:2024 is a special international standard for the determination of ash content in polyamide materials. As the fourth part of the ISO 3451 series of standards, it has formulated special test procedures for the characteristics of polyamide (including filled and unfilled). The standard introduces the automatic equipment method (Method D) for the first time, which is technically synchronized with the main standard ISO 3451-1:2019.

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Comparison of Method Systems

Method Type	Applicable Materials	Temperature Requirements	Special Reagents
Method A	Unfilled Materials	850±50℃	None
Method C	Materials Containing Metal Halide	Sulfuric Acid Treatment	Concentrated Sulfuric Acid
Method D	All Materials	600-850℃	Automated equipment
DBB method	Flame retardant reinforcement materials	≥850℃	Decabromobiphenyl

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Key technology innovation

The main updates of the 2024 version of the standard include: 1) Added Method D automatic equipment method; 2) Clarified the temperature control requirements for DBB method treatment of antimony trioxide flame retardants; 3) Supplemented the secondary calcination procedure when glass fiber is melted. Especially for materials containing brominated flame retardants, the standard emphasizes that they must be operated in a fume hood to prevent the formation of dioxins.

Application Case: Glass Fiber Reinforced Flame Retardant PA66 Test

A certain automobile uses 30% glass fiber reinforced flame retardant PA66 (containing brominated polystyrene), and the DBB method must be implemented according to clause 7.5:

1. Crush the sample to a size of 1cm×0.5cm×0.2cm
2. Add 50% of the sample mass of decabromobiphenyl powder
3. Calcine in a muffle furnace ≥850℃ (forced ventilation)
4. If the first result deviation is >0.76% (repeatability limit), a second calcination is required

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Test accuracy data

The standard provides the precision data of glass fiber reinforced polyamide: standard deviation of repeatability (sr) 0.272%, standard deviation of reproducibility (sR) 0.282%. When the difference between two test results exceeds 0.76% (r value), the experiment needs to be repeated.

Implementation suggestions

• Safety protection: The DBB method must be equipped with a professional exhaust gas treatment system
• Equipment selection: A microwave muffle furnace with programmable temperature control is preferred
• Sample preparation: The filling material needs to be pre-dried to constant weight
• Data comparison: It is recommended to establish an internal quality control sample library

ISO 3451-4:2024 Referenced Document

• ISO 3451-1:2019 Plastics — Determination of ash — Part 1: General methods

ISO 3451-4:2024 history

• 2024 ISO 3451-4:2024 Plastics — Determination of ash — Part 4: Polyamides
• 1998 ISO 3451-4:1998 Plastics - Determination of ash - Part 4: Polyamides
• 1986 ISO 3451-4:1986 Plastics; Determination of ash; Part 4 : Polyamides

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