The devastation of fire is often attributed by the damages due to large amounts of heat, smoke and toxic gases caused by the combustible material ignited, rather than the fire itself.
| Fireproof paint types are shown in [Table 1]. Amongst the fireproof paints, there are intumescent paints that foam and expand in volume by several hundred times when exposed to high heat and flames, where the paint coating itself becoming flame retardant slowing down the base material from reaching the ignition temperature. Others are non-intumescent type that generate flame extinguishing gases to prevent conduction of heat and flames. The latter includes the organic type and non-organic type. |  |
[Table 1] Fireproof paint types
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The purposes fireproof paints are classified based on fire resistant nature of the panted material. If the painted material is flammable, the paint makes the material flame-retardant, and if the material is non-flammable, the coating prevents degradation of the material by paint's heat insulation effect, retarding the fire to spread onto other flammable objects.
The intumescent paints in normal states show the nature of general paints, but when they come into contact with flame, the paint coatings become sponge-like carbon film with thickness several tens to several hundred times, or generate nonflammable gases retarding the base material from reaching the ignition temperature. Therefore, this type is effective on wooden objects that have low ignition temperature. When the wooden objects are coated with fireproof paints, it is said that the amount of gases generated during combustion are reduced to 1/3 to 1/100.
The main ingredients of foaming type are monobasic ammonium phosphate, urea, starch and paraformaldehyde, etc. and they are kneaded with water for application. In the coating film, urea resin is formed from urea and paraformaldehyde becoming the binder. The ammonium salt will begin to decompose at 250℃, and rapidly emits ammonia gas at 290〜300℃, promoting dehydration carbonization of the coating film. The process is as follows.
| 1. | The surface of the coating film is melted by the heat of the fire. |
| 2. | The foaming agent thermally decomposed and generates non-combustible gas, and expands the coating film. |
| 3. | Phosphoric acid-containing catalyst decomposes at lower temperature than the carbonization agent. |
| 4. | By the action of phosphoric acid generated, carbonization agent is dehydration carbonized and becomes flame retardant. |
Flame retardant fireproof paints have flame retardant coating film with self-fire-extinguish function. For example, there are emulsion paints with large amounts of non-organic pigments with flame retardant resins such as vinyl acetate, vinyl chloride, and acrylic as the binder, and a type with flame retardant aids such as antimony trioxide with resin binder made flame retardant by halogen.
Non-flammable paints are completely non-flammable with non-organic pigments blended with non-organic binders. Application of the fireproof paints are for home appliances, furniture, automotive interiors, etc. Especially for the automotive interior applications, other than fireproofing and fire retarding of base materials, soft feels and suede-like tactile finish design have been attracting attention. For example, by coating ABS resin parts with fireproof paints, the hard and cold feel of the parts are made to have warm and soft feel.
