GB/T 39366-2020Leather - Tests for colour fastness - Colour fastness to crocking (English PDF)

Foreword

This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This Standard uses the redrafting method to modify and adopt ISO 20433:2012,

"Leather - Tests for colour fastness - Colour fastness to crocking".

Compared with ISO 20433:2012, this Standard makes the following technical

modifications to adapt to the actual situation of China:

-- Delete the second paragraph in "1 Scope" (see Chapter 1 of ISO

20433:2012);

-- With regard to the normative references, this Standard makes technical

adjustments to adapt to the technical conditions of China. The

adjustments are concentrated in Chapter 2 "Normative references". The

specific adjustments are as follows:

* Use GB/T 251 which is equivalent to the international standard to

replace ISO 105-A03 (see4.3);

* Use GB/T 33729 which modifies and adopts international standards to

replace ISO 105-F09 (see 4.2);

* Use GB/T 39364 which modifies and adopts international standards to

replace ISO 2418 (see 5.1);

* Use QB/T 2707 which modifies and adopts international standards to

replace ISO 2419 (see 5.3);

* Delete the reference to ISO 105-A01 and ISO 105-A04 (see Chapter

2 of ISO 20433:2012);

* Add reference to GB/T 6682 (see 4.4);

-- Delete the description about the test for colour fastness in "3 Principle"

(see Chapter 3 of ISO 20433:2012);

-- Add the requirement that the friction head is a cylinder in "4.1 Test device

for colour fastness to crocking" (see 4.1);

-- Delete "4.4 Spectrophotometer or colorimeter for evaluating staining" (see

1 Scope

This Standard specifies the method for determining the colour fastness to

crocking of the leather surface by using white cotton cloth to rub the leather

surface repeatedly.

This Standard applies to the test of colour fastness to crocking on the surface

of various types of colored leather.

2 Normative references

The following documents are indispensable for the application of this document.

For dated references, only the dated version applies to this document. For

undated references, the latest edition (including all amendments) applies to this

document.

GB/T 251, Textiles - Tests for colour fastness - Grey scale for assessing

staining (GB/T 251-2008, ISO 105-A03:1993, IDT)

GB/T 6682, Water for analytical laboratory use - Specification and test

methods (GB/T 6682-2008, ISO 3696:1987, MOD)

GB/T 33729, Textiles - Tests for colour fastness - Cotton rubbing cloth (GB/T

33729-2017, ISO 105-F09:2009, MOD)

GB/T 39364, Leather - Chemical, physical, mechanical and fastness tests -

Sampling location (GB/T 39364-2020, ISO 2418:2017, MOD)

QB/T 2707, Leather - Physical and mechanical tests - Sample preparation

and conditioning (QB/T 2707-2018, ISO 2419:2012, MOD);

3 Principle

Under specified conditions, rub the leather sample back and forth with the white

cotton cloth (dry or wet) that is placed on the cylindrical friction head; use the

grey scale to assess the staining of the white cotton cloth.

Fix the test surface of the sample upward on the platform of the test device, so

that the length direction of the sample is consistent with the running direction of

the friction head. Carry out the test according to the procedures that are

specified in 6.2 and 6.3.

1 time), to rub 10 times in total; remove the cotton rubbing cloth after rubbing.

7 Result assessment

Use a brush or scotch tape to carefully remove the dust, stains and fibrous

materials remaining on the surface of the cotton rubbing cloth; only consider

the staining of the cotton rubbing cloth due to the color.

Note: During the test, due to the migration of colored substances, such as

coatings, pigments, dyes or dust, color migration which is caused by

other possible reasons on the leather surface, the cotton rubbing cloth is

subject to a certain degree of color pollution.

Place three layers of unused cotton rubbing cloth on the back of each to-be-

assessed cotton rubbing cloth. Under D65 light source, use the grey card for

assessing staining (4.3) to assess the staining grade of the cotton rubbing cloth.

8 Assessment error

The difference between the assessment results of different assessors shall not

be more than half a grade.

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