LY/T 3231-2020Water-based UV-curing coatings on indoor woodenware (English PDF)

4.1 Classified by function

- Top coat;

- Primer.

4.2 According to the purpose of topcoat

- Top coat for floor;

- Top coat for furniture;

- Finish paint for other decoration parts.

5.1 Performance indicators

The performance indexes of water-based UV curable coatings for indoor wood products should meet the requirements of Table 1.

a This item is limited to products that have requirements during storage, transportation and use.

b Floor primer does not control this item.

c The test conditions of the project can also be negotiated.

d This item is limited to products with similar features such as resistance to yellowing.

5.2 Hazardous substances

5.2.1 The substances listed in Appendix A shall not be added artificially in the water-based UV curable coating products for indoor wood products.

5.2.2 The limit of harmful substances in water-based UV curable coating products for indoor wood products should meet the requirements of Table 2.

6.1 Sampling

The product is sampled according to GB/T 3186, or it can be sampled according to the method agreed by both parties in the agreement. The sampling amount is determined according to the needs of the inspection.

6.2 Test environment

The state adjustment of the test sample and the temperature and humidity of the test should meet the requirements of GB/T 9278.

6.3 Preparation of test panels

6.3.1 Substrate and its treatment

The substrate and coating requirements for inspection of each item are shown in Table 3.The light-colored veneer plywood meets the technical requirements of GB/T 15104, and the substrate should be guaranteed no deformation occurs during the test, and it should be placed for more than 7 days under 5.2 conditions before use. Shuiqinggang (beech) solid wood board or other varieties Solid wood flooring meets the requirements of GB/T 15036.1-2018, and the requirements and treatment of glass plates and aluminum plates should meet the requirements of GB/T 9271-2008.

The requirements for white porcelain tiles for external use or white substrates of other materials shall meet the requirements of GB/T 23983-2009, 6.1.

Note. Light-colored veneer plywood can be made of white beech, white maple, white oak and other light-colored varieties.

6.3.2 Requirements for board making

6.3.2.1 General requirements

The prescribed wire bar coater is used for blade coating and board coating, and it can also be coated by curtain coating, roller coating, spray coating, brush coating, etc. after negotiation.

Use the wire bar coater of specification 40, and make the plate according to the requirements of Table 3.The curing conditions shall be indicated in the report.

Note. Size 40 means that the diameter of the winding steel wire tightly wound on the stainless steel rod is 0.40 mm.

6.3.2.2 Preparation of single-coated samples

Curing performance, sandability, gloss, pencil hardness, adhesion (primer) items are scraped out with a single paint, and it needs to be allowed to stand after scraping.

The standing conditions are negotiated by both parties, and then solidified according to the stipulated or agreed conditions.

6.3.2.3 Preparation of composite coating template

Except for the items made according to the requirements of single coating, two coats (ie one bottom and one side) are applied to the other items. After mutual agreement, it can also be scraped with top coat Apply two coats. Before squeegeeing the second coating, use 400# white sandpaper to smooth and wipe off the floating dust on the surface of the sample plate.

Set aside, the standing conditions are negotiated by both parties, and then solidify according to the stipulated or agreed conditions.

6.4 Test method

6.4.1 General provisions

In the test, only reagents confirmed to be chemically pure and above purity and distilled water that meet the requirements of GB/T 6682-2008 for tertiary water are used or deionized water. The test solution is adjusted to the test temperature before the test.

6.4.2 State in the container

Open the container and stir with a knife or stir bar to allow sedimentation at the bottom of the container. If it is easy to mix evenly after stirring, it is rated as "even after stirring no lumps".

6.4.3 Fineness

According to the provisions of GB/T 6753.1-2007.

6.4.4 Storage stability

Put about 0.5 L of the sample into a well-sealed dark plastic tank, leaving about 10% of the space in the tank, and put it in (50±2)°C after sealing.

In a constant temperature drying oven, take it out after 7 days and place it at (23±2)°C for 3 hours, and check the "state in the container" according to 6.4.2.If before storage If there is no obvious difference between the later samples, it is rated as "no abnormality".

6.4.5 Freeze-thaw resistance

Carry out 3 cycles test according to method A in GB/T 9268-2008.

Observe whether the sample has lumps, agglomeration and separation. If not, it is indicated as "not deteriorating".

6.4.6 Curing performance

Under the curing conditions agreed by both parties, use a single UV lamp or a production line with a UV curing device to test, and the curing energy is in milliseconds.

The focal point per square centimeter (mJ/cm2) is expressed (measured with a UV energy meter). The curing performance is judged according to the GB/T 1728-1979 hard-drying method If the coating film can be dried, it is judged as "pass".

6.4.7 Appearance of coating film

The model was observed visually under scattered sunlight. If the coating film is uniform, there is no morbid phenomena such as sagging, blooming, pinholes, cracking and peeling of the coating film, it is rated as "Normal".

6.4.8 Grindability

Use 400