前言
国际标准化组织 (国际标准化组织) 是国家标准机构的全球联盟 (ISO成员机构). 国际标准的制定通常通过ISO技术委员会进行. 每个对已成立技术委员会的主题感兴趣的成员机构都有权在该委员会中派代表参加. 与 ISO 联络的国际政府和非政府组织也参与了这项工作. ISO 与国际电工委员会密切合作 (国际电工委员会) 关于电工标准化的所有问题.

国际标准是按照第 2 部分给出的规则起草的。 2 ISO/IEC 指令的.

技术委员会的主要任务是制定国际标准. 技术委员会通过的国际标准草案将分发给成员机构进行投票. 作为国际标准的出版至少需要获得批准 75% 成员机构的数量.

请注意，本文档的某些内容可能受专利权保护. ISO 不负责识别任何或所有此类专利.

国际标准化组织 2493-1 由 ISO/TC 技术委员会编写 6, 纸, Board and Pulp, 小组委员会SC 2, Test methods and Quality Specifications for paper and board.

The first version, 与 ISO 一起 2493-2, 取消并取代了技术修订后的ISO 2493:1992. In the revised version, 国际标准化组织 2493:1992 is divided into two parts due to different measurement principles. ISO的这一部分 2493 describes a constant deflection rate, 和ISO 2493-2 describes the Taber type tester. The part can also use a smaller bend length and a lower bend Angle if desired. Added optional computations in index form. A precise note has been added to the informative annex A.

国际标准化组织 2493 consists of the following parts under the general heading Paper and Board – Determination of Bending resistance:

— 部分 1: 恒定偏转率

— 部分 2: Tabor tester

国际标准化组织 2493-1-221 “纸和纸板 – 弯曲度的测定 – 部分 1: 恒定偏转率”

介绍
In ISO 2493:1992, two principles for determining bending resistance are incorporated into the same standard, although the two principles are very different.

One principle involves deflecting the same number of specimens with relative surfaces in the direction of deflection; ISO的这一部分 2493 describes this principle.

Another principle uses a Taber-type tester, in which the specimen is inserted and deflected to the top, and then deflected in the opposite direction without altering the specimen. This principle is described in ISO 2493-2. This method is based on TAPPI test method T 489 om-04[4].

1 范围
ISO的这一部分 2493 specifies procedures based on the two-point loading principle for determining the flexural resistance of paper and board.

笔记 1 参见 ISO 5628[1] for a detailed explanation of the two-point loading principle.

ISO的这一部分 2493 is suitable for measurement of bending resistance in the range 20 mN to 10 000 毫牛. It does not work with corrugated board, but it can work with components of such board.

The bending Angle is 15° and the bending length is 50 毫米.

For samples where the bending resistance is too low to measure a bending length of 50 毫米, a shorter bending length of 10 mm can be used.

Important note – Results obtained with different bending lengths will not be comparable.

For boards that tend to permanently deform when bent at 15°, a semi-bending Angle of 7,5 ° can be used.

Note 2Taber type tester and tester using the principle of constant deflection cannot give comparable results. 所以, 国际标准化组织 2493:1992 is divided into two parts.

2 规范性引用文件
The following reference documents are not available or available for use in this document. 对于注明日期的参考文献, 仅引用版本适用. 对于未注明日期的参考文献, 新版本的参考 (包括任何修订) 适用.

国际标准化组织 186, 纸和纸板 — 抽样以确定平均质量

国际标准化组织 187, 纸, 纸板和纸浆 — 用于调节和测试的标准大气以及用于监测样品大气和调节的程序

国际标准化组织 536, 纸和纸板 – 克重的测定

3 术语和定义
就本文件而言, 以下术语和定义适用.

3.1 Bending force

The force required to bend a rectangular specimen with one end clamped, measured under the conditions specified in this part of ISO 2493

3.2 Flexural resistance

The average of all valid readings of the measured bending force (3.1) calculated as specified in this part of ISO 2493

笔记 1: Flexure is expressed in Newtons or millinewtons.

3.3 Bending Length

The radial distance between the fixture and the position of force applied on the sample under test is constant

笔记 1: See l in Figure 1.

3.4 弯曲角度

The Angle of rotation of the fixture as it moves from its initial position to the position where bending resistance is measured

3.5 Free Length

The total length of the specimen protruding from the fixture

笔记 1: See L in Figure 1.

3.6 flexural index

Bending resistance divided by gram weight to the third power

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