GB/T 19243-2003Rubber, vulcanized or thermoplastic -- Methods of test for staining in contact with organic material (English PDF)

4.2 Method B (assessment of extraction stain): Allow the test liquid to pass over

the surface of the tested rubber, to be in contact with the specified organic

material. If required, the organic material is then thermally-irradiated.

4.3 Method C (assessment of penetration stain): Bond a designated light-

colored thin-layer to the tested rubber. Then the thin-layer is thermally-irradiated.

4.4 Assessment of stain: Use the visual observation method for qualitative

assessment. Use the grey scale for assessment. Use the reflectance

spectrophotometer for assessment.

5.1 Hot-air aging box: It is in accordance with GB/T 3512.

5.2 Artificial light source: A xenon lamp that, through filtering, gives the spectral

distribution equivalent to sunlight, meets the requirements of GB/T 12831,

meets the requirements of 9.1. It is applicable to method A, method B, method

C.

5.3 Radiation chamber: It includes lamp and sample holder, which meet the

requirements of 9.3 and 9.4. It is applicable to method A, method B, method C.

5.4 Thermocouple or blackboard thermometer: See GB/T 12831. It is used to

measure the surface temperature of the specimen. It is applicable to Method A,

Method B, Method C.

5.5 Apparatus for determining light intensity: It in accordance with the

wavelength range as given in 9.1. It is applicable to Method A, Method B,

Method C. It is recommended to use it.

5.6 Blue wool standard parts: It is in accordance with GB/T 730. It is applicable

to Method A, Method B, Method C.

5.7 Gray scale: It complies with the provisions of GB/T 250. It is applicable to

Method A, Method B, Method C.

5.8 Reflective spectrophotometer: The wavelength range is 400 nm ~ 600 nm.

It is applicable to Method A, Method B, Method C.

5.9 Beaker and drip device: It is applicable to method B.

5.10 Drip holder and drying rack: It is applicable to method C.

provisions of GB 6038. Roll the un-vulcanized rubber to a thickness of 2.0 mm

± 0.2 mm. The both sides are protected by inert materials such as starched

cambric cloth or polyethylene film. Cut the film to the desired molded size.

Roll the light-colored thin rubber layer to a thickness of 0.5 mm ± 0.05 mm. Use

a protective aluminum foil at least on one side to flatten it.

When bonding, remove the protective layer from one side of the test rubber and

the thin layer. It may use a plate press or a press roll to apply pressure, to firmly

press the two exposed surfaces together, to ensure that the aluminum foil

remains outside the thin layer.

Place the assembly which contains the aluminum foil in a flat vulcanizer for

molding and vulcanizing. Pay attention to locate the thin layer and the aluminum

foil at the bottom of the mold. The test report shall contain the vulcanization

conditions. The protective layer on the thin layer is retained before the test.

6.3.3 Painted specimens

Immerse the vulcanized rubber specimen in a 25 mm depth paint (see 6.2).

Then hang it on an appropriate holder to dry it. After drying, immerse it in the

paint for the second time. Then dry it again until the surface is not sticky.

Dissolve the un-vulcanized thin rubber layer in a suitable solvent (volume ratio

1:6) to prepare an adhesive paste instead of the paint. The preparation

procedure of the specimen is the same as the preparation procedure of the

painted specimen.

The aluminum foil immersed in the varnish/adhesive paste is used as a blank

specimen.

The thickness of the varnish layer is 0.1 mm ± 0.02 mm. The thickness of the

adhesive paste layer is 0.16 mm ± 0.04 mm.

6.4 Blank specimen and reference specimen

6.4.1 Blank specimen

Except that the tested rubber is replaced by inert material, the blank specimen

and the tested rubber are prepared and processed by the same method. The

appropriate inert material which is used to replace rubber specimen is 0.4 mm

~ 0.6 mm thick aluminum foil.

6.4.2 Reference specimen

The reference specimen has the same structure as the tested specimen (6.1 ~

6.3) and is prepared in the same manner. However, it shall use appropriate

method to avoid light exposure, that is, use appropriate covering during

recommended in clause 9, illuminate the painted surface of the specimen. Then

use the distilled water which contains approximately 2% (mass fraction) non-

alkaline detergent to rinse this sheet. Follow the requirements of clause 10 to

evaluate the penetration stain.

The blank test is carried out in parallel with the stain test. Compare the blank

specimen to evaluate the degree of stain.

9.1 Intensity

The light source is a xenon lamp (see 5.2). The wavelength of the lamp is 300

nm ~ 830 nm. the radiant intensity of the specimen surface is 1000 W/m2 ± 200

W/m2.

9.2 Illumination time

Unless otherwise specified, the suitable illumination time is 24 h, 48 h or 168 h.

Alternatively, illuminate the specimen together with the blue wool standard

piece (see 5.6), until one of the previously selected standard piece 3, standard

piece 4 or standard piece 6 presents a gray color which is equivalent to grade-

9.3 Surface temperature

The surface temperature of the specimen is 55 °C ± 3 °C. Use a blackboard

thermometer (see 5.4) to make measurement.

9.4 Position arrangement of specimen

When several specimens are simultaneously exposed to light, take care to

make all specimens are illuminated equally. The change in radiant intensity at

any point on the surface of the specimen shall not exceed ±10% of the average.

These requirements may be achieved by rotating the specimen around the

xenon lamp.