GB/T 451.2-2023Paper and board - Part 2: Determination of grammage (English PDF)

Foreword

This Document was drafted as per the rules specified in GB/T 1.1-2020 Directives for

Standardization - Part 1.Rules for the Structure and Drafting of Standardizing Documents.

This Document is Part 2 of GB/T 451.GB/T 451 consists of the following parts.

--- Paper and Board - Determination of Size and Deviation (GB/T 451.1);

--- Part and Board - Determination of Grammage (GB/T 451.2);

--- Paper and Board - Determination of Thickness (GB/T 451.3).

This Document replaced GB/T 451.2-2002 Part and Board - Determination of Grammage.

Compared with GB/T 451.2-2002, the major technical changes of this Document are as follows

besides the structural adjustments and editorial modifications.

a) Add the terms and definitions of "oven-dry grammage" and "as-taken grammage" (see

Clause 3 of this Edition);

b) Change the calculation method of the area when the cutting area of the sample cutting

equipment reaches the accuracy (see 5.1 of this Edition, 5.1 of the 2002 edition); add the

accuracy requirements for the measurement size of each specimen when the cutting area

accuracy of the sample cutting equipment does not reach the specified requirements (see

2002 Edition); and add the sampling requirements for as-taken grammage determination

(see Clause 6 of this Edition);

f) Change the description of the standard operation when the available sample area is limited

(see 8.1 of this Edition; 8.1 of the 2002 Edition);

g) Add grammage calculation using paper and board grammage tester (see 9.2 of this

Edition);

h) Add calculation of grammage deviation (see 9.3 of this Edition);

i) Change test report (see Clause 10 of this Edition; Clause 10 of the 2002 Edition);

j) Add determination of oven-dry grammage and as-taken grammage (see Appendix B of

this Edition).

This Document modified and adopted ISO 536.2019 Part and Board - Determination of

Grammage.

Compared with ISO 536.2019, this Document has more structural adjustments. See Appendix

A for a comparison of the structure number changes between the two documents.

The technical differences and causes between this Document and ISO 536.2019 are as follows.

a) Change the description of the Scope (see Clause 1 of this Document; Clause 1 of ISO

536.2019) to comply with the drafting rules of China's national standardization

documents;

b) Add the terms and definitions of "oven-dry grammage" and "as-taken grammage" (see

Clause 3 of this Document) to facilitate user understanding;

c) Change the requirements for balance accuracy selection (see 5.2 of this Document; 5.2 of

ISO 536.2019) to facilitate operation;

d) Deleted the area requirements for the paper and board grammage measuring instrument

to weigh a single piece of specimen (see 5.3 of ISO 536.2019) to adapt to the current

situation of the industry in China;

e) Add instrument oven (see 5.4 of this Document) to facilitate operation;

f) Change the normative references for the sampling of paper and board and the

measurement of the longitudinal and transverse directions and the front and back of the

specimens; and replace ISO 186 with GB/T 450 (see Clause 6 of this Document) to

facilitate industry operation;

g) Change the description of sampling, sampling area and test steps (see Clause 6 and 8.1 of

this Document; Clauses 6 and 8 of ISO 536.2019) to be consistent with the specifications

of the commonly used standard samplers in laboratories and adapt to the current situation

of the industry in China;

h) Change the normative references of standard atmospheric conditions for the processing

and testing of paper, board and pulp specimens; and replace ISO 187 with GB/T 10739

(see Clause 7 of this Document) to facilitate industry operation;

i) Add the determination and result expression of the cross-section grammage difference

(see 8.3 and 9.4 of this Document) to meet the needs of the industry;

j) Add the result expression of the grammage deviation (see 9.3 of this Document) to

facilitate operation;

k) Change the description of the test report (see Clause 10 of this Document; Clause 10 of

ISO 536.2019) and adapt to the current situation of the industry China;

l) Change the normative references for the determination of moisture content of paper, board

and pulp analysis specimens, and replace ISO 287 (see B.1.1 of this Document) with

GB/T 462 to facilitate industry operations;

m) Change the expression of grammage sampling (see B.2.1 of this Document) to facilitate

user understanding.

This Document made the following editorial modifications.

--- Delete Appendix B (Informative) "Precision" of ISO 536.2019.

Please note some contents of this Document may involve patents. The issuing agency of this

Document shall not assume the responsibility to identify these patents.

This Document was proposed by China National Light Industry Council.

This Document shall be under the jurisdiction of National Technical Committee on

Papermaking Industry of Standardization Administration of China (SAC/TC 141).

Drafting organizations of this Document. Zhejiang Karen Special Material Co., Ltd.; Zhejiang

Kaifeng New Material Co., Ltd.; South China University of Technology; Shenzhen Huacheng

Packaging Technology Co., Ltd.; Zhejiang Shanying Paper Co., Ltd.; Chian National Pulp and

Paper Research Institute Ltd.; Sinolight Paper Inspection & Certification Co., Ltd.; and

Sinolight (Jinjiang) Hygiene Products Research Co., Ltd.;

Chief drafting staffs of this Document. Wu Dongle, Zuo Jianbo, Li Liangjun, Feng Yafang, Ye

Huiren, An Tiantian, Wo Qizhong, Wang Bin, Deng Jihui, Chen Hua, Zhang Qi, Luo Manshu,

Cai Fuhan, Chen Ping, Wen Jianyu, Wang Xinting, and Yuan Taojing.

The historical editions replaced by this Standard are as follows.

--- GB 451-1964 was first-time published in 1964; first-time revised in 1979;

--- Second-time revise din 1989; revised the Part 4.Determination of Grammage into GB/T

451.2-1989; third-time revised in 2002;

--- It is fourth-time revised hereby.

1 Scope

This Document describes the determination method of grammage of paper and board.

This Document applies to the determination of grammage of paper and board.

2 Normative References

The provisions in following documents become the essential provisions of this Document

through reference in this Document. For the dated documents, only the versions with the dates

indicated are applicable to this Document; for the undated documents, only the latest version

(including all the amendments) is applicable to this Document.

GB/T 450 Paper and board - Sampling for testing and identification of machine and cross

direction wire side and felt side (GB/T 450-2008, ISO 186.2002, MOD)

3 Terms and Definitions

For the purposes of this Document, the following terms and definitions apply.

The mass per unit area of paper and board measured by the specified test method.

The mass per unit area of paper and board measured when dried to constant weight at 105 degrees C +/-

2 degrees C.

4 Principle

Measure the area and mass of the specimen and calculate the grammage.

5 Instruments

If mass of the specimen is 5 g or less, use a balance with a graduation value of 0.001 g.

If mass of the specimen is more than 5 g and less than 50 g (including 50g), use a balance with

a graduation value of 0.01 g.

It can keep the temperature at 105 degrees C+/-2 degrees C.

6 Sampling

If the test is used to evaluate a batch of samples, the specimens shall be taken according to

GB/T 450.If the test is used to evaluate other types of samples, ensure that the taken specimens

are representative. The number of samples shall be no less than 5 pieces; and the total area shall

be at least enough to cut 20 pieces of specimens.

7 Specimen Treatment

When determining the grammage and oven-dry grammage, the specimen treatment and the

standard atmospheric conditions of the test shall be carried out in accordance with the

provisions of GB/T 10739.

8 Test Procedures

If the sample area is limited and the specified total area of specimen cannot be met, a specimen

with a total area of no less than 0.05 m2 shall be used; and the measurement area of the specimen

shall be noted in the test report.

Weigh the mass of the specimen on a balance (5.2) or a paper and board grammage measuring

instrument (5.3).

9 Expression of Results

10 Test Report

The test report shall include the following information.

Appendix A

(Informative)

Comparison of Structure Numbers between This Document

and ISO 536.2019

......