ISO 10716:2022

Paper and board — Determination of alkali reserve

This document specifies a method for the determination of the alkali reserve of papers and boards. lt is intended for products that contain alkaline pigments or other alkaline material, added to improve their resistance to acid attack (degradation). This document is not applicable to laminated, printed or otherwise processed grades that will not disintegrate completely by the procedure described. The result obtained will include alkaline pigments contained in the coating of a coated paper. NOTE Such alkaline coating will protect the core of the paper from acid substances in ambient air, but its effect on acid substances generated in the base paper itself is uncertain.

Papier et carton — Détermination de la réserve alcaline

General Information

• Status: Published
• Publication Date: 10-Feb-2022
• ICS: 85.060 - Paper and board
• Technical Committee: ISO/TC 6 - Paper, board and pulps
• Drafting Committee: ISO/TC 6/WG 4 - Chemical analysis
• Current Stage: 6060 - International Standard published
• Start Date: 11-Feb-2022
• Due Date: 06-Jan-2023
• Completion Date: 11-Feb-2022

Relations

• Referred By: EN ISO 9706:2025 - Information and documentation - Paper for documents - Requirements for permanence (ISO 9706:2025)
• Effective Date: 09-Feb-2026
• Revises: ISO 10716:1994 - Paper and board — Determination of alkali reserve
• Effective Date: 26-Nov-2021

Overview

ISO 10716:2022 establishes a standardized method for the determination of the alkali reserve in paper and board materials. The alkali reserve is crucial for evaluating the resistance of papers and boards to acid attack, which can cause degradation and reduce long-term stability. This international standard is particularly relevant for paper products containing alkaline pigments or materials designed to enhance their durability in various environmental conditions.

The method defined by ISO 10716:2022 is applicable to papers and boards intended to resist acid degradation, commonly used in archival, library, or permanent document applications. However, it does not apply to laminated, printed, or otherwise processed grades that cannot be fully disintegrated by the prescribed procedure.

Key Topics

• Alkali Reserve Definition
  Alkali reserve refers to compounds (such as calcium carbonate) present in the paper that neutralize acids generated either by natural aging or through exposure to atmospheric pollutants.

• Scope of Application
  The standard applies to papers and boards with alkaline additives but excludes materials that cannot undergo complete disintegration via the procedure, such as certain processed or laminated grades.

• Test Methodology
  The core of the method involves:

  • Digestion of a representative sample in water with hydrochloric acid.
  • Titration of the remaining acid with sodium hydroxide to determine acid neutralization.
  • Calculation of alkali reserve in moles per kilogram, ensuring results account for all alkaline substances present, not just calcium carbonate.

• Sample Requirements
  Careful sampling and preparation are essential to ensure representative and accurate results for determining the alkali reserve.

• Reporting and Precision
  Results must be reported with reference to ISO 10716:2022, including all critical details on test conditions, method deviations, and findings. The standard prescribes a precision criterion for duplicate determinations.

Applications

Implementing ISO 10716:2022 adds practical value to several sectors:

• Preservation and Archival Industry
  Libraries, archives, and institutions handling permanent records need to ensure paper longevity. Papers with a verified alkali reserve, as measured by this standard, are preferred for long-term storage and protection against acid degradation.

• Paper Manufacturing
  Producers of paper and board can certify their products' resistance to acid attack, enhancing marketability for applications requiring durability and permanence.

• Quality Assurance
  Paper converters and end-users can use the standard to verify compliance with permanence specifications and industry requirements.

• Regulatory Compliance
  Ensures that papers meet international standards for durability, particularly where legal or historical documents are concerned.

Related Standards

For effective implementation and broader quality assurance, ISO 10716:2022 should be used alongside related standards, including:

• ISO 186: Paper and board - Sampling to determine average quality
  Provides guidelines for sampling, an essential step for consistent alkali reserve determination.

• ISO 287: Paper and board - Determination of moisture content of a lot - Oven-drying method
  Used to determine the dry matter content, a prerequisite for accurate alkali reserve calculations.

• ISO 638-1: Paper, board, pulps and cellulosic nanomaterials - Determination of dry matter content by oven-drying method - Part 1: Materials in solid form
  Supports precise measurement of sample mass and content crucial to the calculation of alkali reserve.

By adhering to ISO 10716:2022, industries reinforce the reliability and durability of paper products for archival, legal, and high-durability uses, supporting the preservation of vital documents and compliance with international quality standards.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 10716
Second edition
2022-02
Paper and board — Determination of
alkali reserve
Papier et carton — Détermination de la réserve alcaline
Reference number
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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or ISO’s member body in the country of the requester.
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
5.1 Hydrochloric acid . 2
5.2 Sodium hydroxide solution . 2
5.3 Methyl red . 2
6 Apparatus . 2
7 Sampling and preparation of test pieces . 2
8 Procedure .2
9 Calculation . 3
10 Precision . 3
11 Test report . 3
Annex A (informative) Precision . 4
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 6, Paper, board and pulps.
This second edition cancels and replaces the first edition (ISO 10716:1994), of which it constitutes a
minor revision. The main changes are as follows.
— Clause 2 has been updated.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
Papers produced to be stable for long time periods normally contain some alkaline filler, such as calcium
carbonate, as an alkali reserve to prevent attack from acid substances in ambient air or formed by
deterioration of substances in the paper. Specifications for paper permanence can require a minimum
alkali reserve.
The required alkali reserve is obtained by adding some form of calcium carbonate to the paper furnish
but other substances can also be used for this purpose. By expressing the test results in moles per
kilogram of alkaline substances and not as a calcium carbonate content, no confusion arises when
alkaline substances other than calcium carbonate a
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