Security is the minimum need for human survival and development. Most of the raw materials, semi-finished products and products used in the synthesis of unsaturated polyester resin and the production of composite materials are flammable, explosive, toxic and corrosive, and the production process is continuous and the process is complex, There are certain potential dangers in the synthesis of unsaturated polyester resin and the production process of composite materials.Once an accident occurs, it not only affects the normal production order, but also threatens the personal safety and health of producers. Some accidents even cause serious damage to society and the environment. Therefore, it is necessary to understand the toxicity, combustion performance, explosion characteristics and safe operating rules of the chemicals involved in the synthesis and use of unsaturated polyester resin and the production of composite materials, and establish and improve chemical use and management regulations to ensure the production process. To ensure the safety and health of producers and prevent work-related accidents and occupational diseases.
The toxicity classification of substances is generally based on the lethal oral dose to rats, see Table 1-1. The toxicity of hazardous substances commonly used in the unsaturated polyester resin molding process is shown in Table 1-2.
■Table 1-1 Toxicity of commonly used harmful substances in unsaturated polyester resin molding process
| Toxicity and classification | Oral administration to rats LD50/(mg/kg) | Potentially lethal dose for humans/g |
| Extremely Poisonous | ≥1 | 0.06 |
| Highly Toxic | 1-50 | 4 |
| Toxicity | 50-500 | 30 |
| Mild Toxicity | 500-5000 | 250 |
| Non-toxic | 5000-15000 | 1200 |
| Relatively Harmless | >15000 | >1200 |
Note: LD50 refers to the dose that causes the death of half of the experimental mice (1kg weight) after one dose.
■Table 1-2 Toxicity of hazardous substances commonly used in unsaturated polyresin molding process
| Name | Toxicity LD50 | Hazardous |
| Maleic Anhydride | 400-800 | Irritation to eyes and respiratory tract |
| Phthalic Anhydride | 800-1600 | Irritation to eyes and respiratory tract |
| Hexachloro-1,3-isopropylidenebis(4,4′-cyanurate) | 2000-3000 | / |
| Tetrabromophthalic Anhydride | / | Irritation to skin and mucous membranes |
| Cyclohexanone Peroxide | 50-500 | Severe poisoning, inhalation will cause organ damage |
| Methyl Ethyl Ketone Peroxide | / | Vapor can irritate or even harm eyes and respiratory system |
| Cyclohexanecarboxylic Acid Cobalt Salt | 4000-5000 | Inhalation will cause organ damage |
| Cyclohexanecarboxylic Acid Manganese Salt | >6000 | / |
| Ethylene Glycol | 5500 | / |
| Diethylene Glycol | 20700 | / |
| Methyl Methacrylate | 8400 | / |
| Acetone | 5500 | Irritation to skin |
| Styrene | 5000 | Irritation to skin and respiratory tract, poisonous by inhalation |
| Fiberglass | / | Skin irritation, difficulty breathing, lung disease |
| Carbon Fiber | / | Skin irritation, difficulty breathing, lung disease |
| Filler | / | Shortness of breath, lung disease, some fillers may cause cancer |
| Unsaturated Polyester Resin | / | Irritation to skin and eyes, mist is highly toxic |
According to the oral toxicity standards of substances, the raw materials used for molding unsaturated polyester resin are basically moderately toxic and slightly toxic, and the raw materials with slight toxicity account for the majority. However, long-term exposure to these raw materials will still cause certain harm to human health. of. For example, when producing unsaturated polyester resin-based composite materials, we are often exposed to styrene. Although it is of low toxicity, long-term exposure can cause symptoms such as neurasthenia, nausea, loss of appetite, and decrease in white blood cells. Phthalic acid is highly toxic. When phthalic acid is inhaled into the human body, it will severely damage the liver and interfere with gastrointestinal function.
Styrene is a flammable product. Styrene vapor and air can form an explosive mixture, which can cause a combustion explosion when exposed to an open flame or high heat energy. Styrene can react strongly with strong oxidants and release a large amount of heat, which may cause the reaction vessel to rupture or even explode. Therefore, attention should be paid to environmental ventilation when using it.
Peroxide initiator is a commonly used initiator for unsaturated polyester resin. Because it contains peroxy group -O-O-, its structure is unstable and prone to reactions. It is a flammable and explosive highly active compound such as methyl ethyl ketone peroxide. It is the most widely used room temperature initiator and is extremely flammable and explosive. When exposed to open flames or high-temperature environments, as well as excessive friction or severe vibration or violent impact, it may burn or explode. Therefore, when using methyl ethyl ketone peroxide, Care should be taken during the process.
Reinforcements and fillers can also be harmful to human health. For example, fiberglass can irritate people’s skin and cause skin cancer, itching and dermatitis; long-term exposure to asbestos powder fillers will cause a large amount of asbestos powder to be inhaled into the body and then adhere to and deposit in the lungs, causing lung diseases. If a person is exposed to an environment containing asbestos fibers for a long time, it may cause occupational diseases such as lung cancer and gastrointestinal cancer, and the symptoms of asbestos-related diseases often have an incubation period of more than ten years or even decades. Therefore, reasonable protection must be taken when engaging in relevant occupations.
Powdered materials dispersed in the air can also cause harm to the human body, so care should be taken during operation. If there is flying dust, a mask must be worn before operation. There are four levels of dust hazards: Level 1, highly hazardous dust, such as heated silica, crocidolite, blue asbestos, etc.; Level 2, hazardous dust, including quartz, silica, and asbestos other than crocidolite, etc. Level 3, moderately hazardous dust, such as talc, mica, kaolin, diatomaceous earth (unheated), cotton dust, graphite, etc.; Level 4, weakly hazardous dust, such as sandstone, barite, emery , cement, glass and glass fiber, iron oxide, limestone (excluding silica), magnesium oxide, dioxide, zinc oxide, halo oxide, cobalt silicate and other silicates, etc.