1. Scope
1.1 This practice describes a solvent friction technique to evaluate the solvent resistance of organic coatings based on chemical changes during curing. The technology can be used in the lab, in the field, or in assembly plants. The material D4752 is the preferred choice for the ethyl silicate zinc-rich primer.

1.2 This practice does not specify the solvent, the number of frictions and the desired test results.

1.3 These values are in International system units as standard. Those values in parentheses are for reference only.

1.4 The purpose of this standard is not to address all security concerns, if any, in conjunction with its purpose. It is the responsibility of the user to determine the safety and health practices suitable for this standard and to determine the suitability of supervision and management before use. When it comes to the use of solvents, consult the supplier’s safety data sheet for some special dangerous goods.

ASTM D 5402-1993 Evaluation of Solvent Resistance of Organic Coatings by Solvent Wipe Method

2. Reference materials
2.1 ASTM Standard:

D235 Mineral Specification (Petroleum) (Hydrocarbon dry cleaning solvent)

D5823 Tests materials that reflect gloss

Instruction manual for D740 methyl ethyl ketone

D843 Specification for nitration grade xylene

D1186 is a non-destructive measuring material for dry film layers in non-magnetic coatings containing iron

D1400 is a non-destructive measuring material for dry film layers in insulating coatings that do not contain iron

D3363 Test material for the hardness of thin layers with a pencil

D4138 Uses destructive methods to measure test materials for protective coating systems

D4752 Test material for MEK solvent resistance of ethyl silicate (inorganic) zinc-rich primer by solvent friction method

ASTM D 5402-1993 Evaluation of Solvent Resistance of Organic Coatings by Solvent Wipe Method

3 Terminology
3.1 Specific term definition of this standard:

3.1.1 Double Rub — Perform a back-and-forth rub with cloth on a coated surface.

4. Meaning and use

4.1 Chemical changes in the curing process of coatings, such as epoxy resins, vinyl esters, polyester fibers, alkyd resins and polyurethane rubber, can become more solvent resistant. These coatings should be able to achieve a specific solvent resistance level, make an excellent finish, and function in public institutions. The need for solvent resistance levels varies according to the type of paint and the intended place of use. Rubbing a cloth wet with a suitable solvent is a method of determining whether it has achieved a specific resistance to solubility. However, THE LEVEL OF SOLVENT RESISTANCE ITSELF does NOT MEAN THAT IT IS FULLY CURED. Some coatings become solvent resistant before they are fully cured.

4.2 The time required to achieve a specific level of solvent resistance is affected by temperature, layer thickness, air flow, hydrophily or water-reactive coating and humidity.

4.3 The solvents tested are affected by the type of paint variety and the solvent used. Paint manufacturers may require specified solvents, double rub times and specific test results.

ASTM D 5402-1993 Evaluation of Solvent Resistance of Organic Coatings by Solvent Wipe Method

5. Materials and equipment
5.1 Solvent:

5.1.1 Methyl ethyl ketone (MEK), following the instructions of D740.

5.1.2 Minerals, follow the instructions for D235.

5.1.3 Xylene, follow the instructions of D843.

5.1.4 Other solvents, as specified by the manufacturer or user

5.2 A mesh level of 28*24, approximately 300*300mm (12*12), and the color of the paint contrast 100% cotton cotton cloth, or other similar cloth.

5.3 Select appropriate safety equipment according to MSDS of solvent, such as soluble resistant gloves and gas masks

ASTM D 5402-1993 Evaluation of Solvent Resistance of Organic Coatings by Solvent Wipe Method

6 Production
6.1 Select an area at least 150mm long on the coating surface for testing. Wash with running water to remove any loose material and allow to dry.

6.2 Measure the coating thickness of the selected area to conform to the test materials D1186, D1400 and D4138. Mark a 150*25MM rectangular test area with a pencil on an undamaged and clean surface or with other suitable solvent resistant markers.

6.3 Fold the cotton cloth into two layers and wet it with the specified solvent. The interval between the next step and the next step should not exceed 10 seconds.

6.4 Take proper protection by placing the index finger in the center of the pad while holding the excess cotton cloth between the thumb of the same hand. Test the surface with your index finger at an Angle of 45° and rub back and forth over the rectangular test area with moderate pressure. A single movement from one direction is a double rub, and the speed of completion is close to one second at a time.

6.5 Continue to wipe the test area for a total of 25 completions. Be careful to stay within the rectangular area.

6.6 If additional friction solvent is specified, reassign fingers to an unused clean cotton cloth area, and re-adjust to allow the selected solvent to moisturize it, and continue rubbing on the newly marked area at intervals of no more than 10 seconds, and do another 25 double brushes. Repeat this step until the specified test criteria.

6.7 Immediately check the change of nail strength and vision on the 125mm surface in the middle of the friction area, ignoring the edge 13mm, and compare the friction area with the adjacent non-friction area. As the recovery time increases, the gloss and hardness will return to the initial values. If NUMERICAL values or grades are expected, gloss should be measured according to test material D523 and pencil hardness should be measured according to test material D3363. The same material as in 6.3 is used to measure the thickness of the thin layer in the friction area. Check the cotton cloth visually for signs of exfoliated paint.

ASTM D 5402-1993 Evaluation of Solvent Resistance of Organic Coatings by Solvent Wipe Method

7. Report
7.1 Report, as a minimum, the following information:

7.1.1 Solvent use

7.1.2 The number of double erasers

7.1.3 Thickness of thin layer before and after friction

7.1.4 Visual inspection of the results of the coating coming off the cotton cloth

7.2 The remaining information, such as temperature, humidity and climate conditions, can affect the test results between the application of the coating and the control of the test, and can be reported at any time

ASTM D 5402-1993 Evaluation of Solvent Resistance of Organic Coatings by Solvent Wipe Method

8. Accuracy and bias
8.1 Accuracy – Accuracy is determined

8.2 Bias – Because there is no accepted reference material, bias is uncertain

9. Keywords

9.1 Paint; Curing properties; Double rub material; To dry or cure; Paint; Recoating time; Solvent resistance; Solvent friction material