GB/T 22899.1-2008Paper and board -- Measurement of hygro-expansivity -- Part 1: Hygro-expansivity up to a maximum relative humidity of 68% (English PDF)

Foreword

GB/T 22899 "Paper and board Determination of wet expansion" is divided into two parts.

--- Part 1. Maximum relative humidity 68% expansion to wet process;

--- Part 2. Maximum relative humidity 86% to wet expansion process.

This is Part 1 GB/T 22899 of.

The partial modification of the use of ISO 8226-1:1994 "Paper and cardboard wet expansion coefficient - Part 1. The maximum relative humidity is increased Wet process 68% overrun. " this part of ISO 8226-1:1994 as compared to the main differences are as follows.

--- International Standard ISO document standard will be referenced in the normative references converted to its corresponding national standard, GB/T 450 Paper and cardboard to take samples and specimens to the vertical and horizontal, positive and negative determination (GB/T 450-2008, ISO 186:2002, MOD);

--- International Standard ISO document standard will be referenced in the normative references converted to its corresponding national standard, GB/T 451.2 Paper and cardboard quantitative determination (GB/T 451.2-2002, eqv ISO 536:1995);

--- International Standard ISO document standard will be referenced in the normative references converted to its corresponding national standard, GB/T 10739 paper, paperboard and pulp sample processing and testing standard atmospheric conditions (GB/T 10739-2002, eqv ISO 187:1990).

This section of Appendix A normative appendix.

This part is proposed by the China National Light Industry Council.

This part of the National Standardization Technical Committee under the jurisdiction of the paper industry.

This section drafted by. China Pulp and Paper Research Institute, the national paper quality supervision and inspection center, China Paper Association Professional Committee of Standardization Members will.

1 Scope

This section GB/T 22899 specifies the method of determining the relative humidity of paper and cardboard from (33 ± 2)% ~ under (66 ± 2)% balance Methods of moisture expansion.

This section applies to ordinary paper and paperboard, not for crepe paper and corrugated cardboard.

2 Normative references

The following documents contain provisions which, through reference GB/T 22899 in this section constitute provisions of this section. For dated reference documents Member, all subsequent amendments (not including errata content) or revisions do not apply to this section, however, encouraged to reach under this section Parties to research agreement to use the latest versions of these documents. For undated reference documents, the latest versions apply to this section.

GB/T 450 and take samples to an aspect of paper and paperboard samples, positive and negative determination (GB/T 450-2008, ISO 186.

2002, MOD)

GB/T 451.2 Paper and paperboard quantitative determination (GB/T 451.2-2002, eqv ISO 536:1995) GB/T 10739 paper, paperboard and pulp sample processing and testing standard atmospheric conditions (GB/T 10739-2002, eqv ISO 187.

1990)

3 Terms and Definitions

The following terms and definitions apply to this part of the GB/T 22899 of.

Known length of paper or paperboard, balance and relative humidity from a lower value to a predetermined higher value during a predetermined length of its occurrence the change.

Length change can be expressed as a percentage of the length of the paper or paperboard at a relative humidity of 50% measured at equilibrium conditions.

Note. The sample is considered contraction absorbent expansion is negative.

Principle 4

To ensure that all samples were tested from a humidity level similar to the initial relative humidity, this section contains a pre at low relative humidity Processing step.

At (23 ± 1) °C, 0 load and (22 ± 3)% relative humidity, temperature and humidity conditions of the sample pre-treatment. Then (33 ± 2)% and Under (66 ± 2)% relative humidity, the sample to be appropriate load and quantitative changes in length of the specimen was measured. It may represent a change in length as a percentage of 50% of the measured length relative humidity.

5 Apparatus and materials