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Properties of paints

1) What are the differences among acrylic, urethane, silicone and fluorine?

The most weather resistant and durable is acrylic, followed by urethane, silicone, and fluorine in this order. Regarding expected useful life, the longest is fluorine (15-20 years), followed by silicone (10-15 years), urethane (8-10 years), and acrylic (5-8 years).

2) Which is more excellent, one-pack paints or two-pack paints?

Two-pack paints are quick curing type and are applied to a variety of substrates. It excels one-pack paints in permeability and adhesion to substrate.

3) What is the difference between elasticity and flexibility?

The paint film of elastic paints stretches and covers cracks. So, it prevents rainwater from penetrating into the substrate. Elastic paints are also called waterproof type. Their paint film demonstrates high tension ratio. (See tension test.)

Although flexible paints do not have so much elongation as elastic ones, heir paint film is flexible. (See flexibility test. No crack appears on the surface when the material is bent about -90°.) It is also called mild elastic paint film.

Tension test                                                      Flexibility test

4) Does gloss finish paint film have longer expected useful life?

No, gloss has almost nothing to do with the expected useful life.

5) Are gloss finish paints more resistant to dirt than matt finish ones?

Gloss finish paints generally attract less dirt due to their smooth surface than matt ones. Removing dirt is also easier from a gloss surface than a matt surface.

6) What kinds of gloss do you have?

We have 5 levels of gloss for some products, such as gloss, 70% gloss, semi gloss (50%), 30% gloss and matt. However, even if gloss level is the same, different products provide different gloss impression.  

7) Do heat reflective paints reduce the rise in indoor temperature?

When we conducted an experiment with a house, the temperature was effectively reduced by 3-5℃. However, heat reflective effect depends upon several factors, such as a building structure, types of heat reflective materials, the way they are used, ventilation system, the area of opening, location and application specification. Therefore, the effect of reducing room temperature cannot be guaranteed.

8) Do different colours of heat reflective paints bring different results?

Generally speaking, the surface temperature of dark (less bright) coloured paint is higher than that of light coloured paint. So, the temperature differences between ordinary paints and heat reflective paints will be greater as the colours of paints get darker. That means the difference of solar reflection rates is big at dark colours and small at light colours. (See the following figure.)

                     Brightness and solar reflectance

                                               Brightness

9) What is the difference between sealer and filler?

Sealer is an undercoat material suitable for absorbable substrate such as cement rendering or concrete. It improves adhesion to substrate, just like glue. Filler is suitable to repair cracks, fill unevenness in a surface, and smooth it.

  

10) Should we apply paints as thick as possible?

All the paints have the appropriate consumption specific to products. So, please apply the paints according to their instruction. Thick coating would not guarantee longer period of performance. It may sometimes cause paint drip marks or pinholes.

11) What are the advantages of breathability or vapour permeability of paints?

The breathability and vapour permeability of paint film prevent vapor accumulation inside as well as blisters.

12) What is the difference between water-based paints and solvent-based paints?

Water-based paints are environmentally friendly due to less odour comparing with solvent-based paints. However, they cannot be used when the temperature is lower than 5℃. Therefore, solvent-based paints are suitable for colder regions. They do not have much difference in properties.

13) How thick should paint film be?

The paint film thickness of spray tile and pottery stone type has to be 0.5-3 mm; that of stucco 1-5mm; and that of ordinary paints (emulsion or anti-rust) about 30μ (0.03mm).

14) I have the impression that water-based paints are dissolved by rain after drying. Is it OK to use water-based paints for exterior walls?

Water-based paints form paint film through resin welding when drying. Once the film is formed, it will not dissolve.

15) Is there any problem when water-based paints are applied over solvent-based paints?

When water-based paints are applied over solvent-based paint, undercoat (sealer) has to be applied. Then, there will be no problem. However, when solvent-based paints are applied over water-based paints, some problems including blisters or shrinkage may occur due to the damages on the old paint film. Please apply the materials only after patch test.