Discussion on Safety Technology of Coatings and Coating Operation (4)

Table 5 Minimum ignition energy for solvents commonly used in paints (10-3 joules)

Solvent name

concentration(%)

Minimum ignition energy 10-3 joules

in the air

Carbon disulfide

6.52

0.015

Ethylene oxide

7.72

0.105

1, 3-Butadiene

3.67

0.17

Acetaldehyde

7.72

0.376

benzene

2.71

0.55

Butanone

3.67

0.53

acetone

4.97

1.15

ammonia

21.8

0.77

Toluene

2.27

2.5

Pyrrole

3.83

3.4

4 EDM and static electricity

High-voltage piezoelectric spark discharge can produce sparks on high-voltage electrical equipment in electrostatic spraying equipment or generate sparks during electrostatic discharge, generate short-lived solitary discharge and weak sparks on contacts (such as electrostatic painting, electrostatic spraying, and its voltage is generally 20KV-70KV, some even as high as 100KV), are often seen in the factory, although the discharge energy of these sparks is very small, but for flammable gases that require little ignition energy, flammable liquid vapors, Explosive dust can also pose a great threat. In fact, in places where dangerous goods are present, explosions are common due to fires caused by power, lighting, and electrical equipment used.

According to relevant data, the minimum ignition energy of flammable gas in the air is about 2×10-4 joules, so when the combustible gas reaches a certain concentration in the air, it will be easy to encounter the accumulation of static electricity in the air to discharge sparks. There is a danger of fire.

The data shows that most of the flammable liquids have very high insulation properties. No matter whether they are aliphatic hydrocarbons or aromatic hydrocarbons, their resistivity is about 1013 ohm·cm. The literature shows that liquids with resistivity greater than 1012 Ω·cm can generally be presented. The phenomenon of electrification, according to the above, is not surprising in the case of flammable liquids such as benzene, gasoline, carbon disulfide, ethyl ether, and ethyl acetate.

In places where solvents are present, the prevention of sparks and accumulation of static electricity are the basic guarantees for safe production.

5 In addition, many solvents have direct harm to human health

Everyone knows that benzene can cause benzene poisoning. Experts call benzene a killer with a special aromatic smell. The World Health Organization has also identified benzene as a carcinogen. When people inhale high concentrations of toluene or xylene in a short period of time, symptoms of central nervous system paralysis will appear, lightness may cause dizziness, headache, nausea, chest tightness, and fatigue, and severe cases may cause coma and death due to respiratory failure.

Solvent coatings contain 50% or more of organic solvents, so they should be highly valued in terms of safety production and human health.

5 Additives

Such as lead-containing catalysts, amines, anhydrides and other curing agents, such as ethylenediamine, they not only have the risk of volatile, flammable and explosive, but also toxic, have such and such damage to the human body, some also With an unpleasant pungent odor, the antifouling agent used in marine antifouling coatings is an organotin compound that has been banned due to its high toxicity and contaminating the sea.

6 Conclusion

In recent years, human poisoning, fire and explosion accidents have occurred during the production of coatings and the construction of paints, which have brought huge losses to the national economy and personal safety. The safety education and management of coating production and painting operations should be strengthened. It is necessary to educate the paint, coating and related industries about accident prevention and safety quality throughout the country. Will prevent the occurrence of malignant accidents. Suggest:

1 In conjunction with the opportunity of China's accession to the WTO, we will strengthen the safety legislation in paint production and painting construction as soon as possible. According to the actual situation in China, relevant experts should be organized to formulate a series of safety regulations and standards as soon as possible.
2 Calls on countries and enterprises to increase investment in safety scientific research funding and increase accident prevention countermeasures, etc., organize the exchange of scientific research achievements in safety, raise awareness of safety in the entire country, and eliminate human-caused disasters and reduce the occurrence of malignant accidents.