Epoxy curing agent toxicity and safe operation
Foreign scientists that energy and application of epoxy resin curing agent toxicity is the two issues can not be avoided. Therefore, the curing agent toxicity studies very seriously, focus on the curing agent toxicology test data on which the LD50 LD50 index as the main target. The so-called semi-lethal dose, that is, groups of animals (such as a group of rats) 50% lethal amount of drugs Liu, in mg / kg of the unit said. This is a curing agent that acute toxicity data. In addition, sub-acute test (the results may only be 90 days) and chronic toxicity (2a before it may be the result) data.
First, the toxic effects of curing agent
Curing agent of physical and chemical nature of the toxic influence. Such as the curing agent is liquid or solid, and its toxic effects are not the same, solid attached to the skin easily, and there are vapor pressure of liquid present. In general, the chemical activity of a large curing agent, then the biomass activity is also strong, lead poisoning, it seems to become law. Curing agent toxicity in the following areas.
1, the acute toxicity. Generally use the LD50 said. Amine curing agent toxicity is relatively strong. Most organic polyamines on rat respiratory tract irritation lethal vapor concentration of LD50 values of about 1000 ~ 12000ug / g, exposure time 4 ~ 6h. Primary amine, secondary amine tertiary amine stronger than irritating, toxic aromatic amines larger than the aliphatic amines. If the toxicity of m-phenylenediamine diethylenetriamine than 10 times more toxic. Pyridine, piperazine can cause liver and kidney damage, have greater systemic toxicity. Anhydride type curing agent can lead to dermatitis, and oral toxicity is relatively small.
2, the skin, mucous membrane stimulation. Curing agent poisoning, more important is reflected in the skin and mucous membrane irritation on. Because the amine is an organic base, soluble in water and fat, so fat can be dissolved in the skin, soaked, causing dermatitis. Long period of stimulation, easily lead to generalized inflammation of the skin strong, punctate erythema, the formation of blisters, cracking or even the formation of flake falling off, so that tissue necrosis. Hine, who carried out detailed research, the results shown in Table 3-52. Since amines have greater volatility, and its vapor irritates the eyes can cause conjunctivitis, tearing and corneal edema. In the high concentration range or long-term exposure to higher concentrations, will also significantly stimulated the respiratory tract, may cause tracheitis, bronchitis. Anhydride type of skin irritation is weak, but it's dust eye and nose, throat and other respiratory tract mucosa to stimulate a very strong, can cause bronchitis.
3, the curing agent of allergic effects. The so-called allergies, that is, once a compound effect on human skin, the formation of allergic body, or after the next contact repeatedly, not because of how the degree of exposure, dermatitis may also occur. After this occurs, you should break contact with the work of this kind of allergic compounds. More complex role in the occurrence of allergy, is continuing the use of Ciba's research Wanru pudding tests on animals for research. U.S. Plastics Industry Association (SPI) introduced their own standards.
4, curing agents and other toxic effects. In addition to aromatic amines, heterocyclic amine curing agent of visceral damage, biphenyl carcinogenic aromatic amine, has banned the production and use. M-phenylenediamine, diamino diphenyl sulfone has been confirmed for many toxicology workers not carcinogenic, be denied to the previous view.
Second, the use of the safe operation of curing agent
1, the curing agent with low toxicity to replace the toxic.
2, to improve the operating environment, operation of the operating area and non-conscious area gash, as automated as possible, tightly closed, install ventilation, and so on.
3, strengthen labor protection, the use of protective gloves, clothing and other measures to avoid skin contact with the curing agent.
4, the operation time cleaning establishments to maintain health.
5, timely cleaning hands, face and other exposed skin, if the eyes, throat and other organs have been infringed, you should ask the doctor to deal with.
Third, the toxicity of other related compounds
1, the epoxy resin (bisphenol A-type main discussion) of raw materials
Epichlorohydrin: Because epoxy, the presence of chlorine substituents, considerable toxicity in the 240ug / g environment can make 4h mice died. Gage made the maximum allowable value of MAC is 5ug / g, the other eye, nose and throat irritation are also high; Bisphenol A: Borman proposed LD50 of 2.4g/kg, so that the industry is very small harmful.
2, bisphenol A type epoxy resin Epon815, 820,828,1001,1007, and resorcinol ether compounds, have been proven to be very low toxicity, usually in the 10 ~ 30g/kg LD50 values range. Hine, who believe that thinner single ether compounds toxicity, mainly in the stimulation of the skin, the oral LD50 value is very low.
3, the toxicity of cured epoxy resin to cure the common epoxy resin (in octyl phthalate, the content of 50% to 70%) mixed in food (about 10%), by mouth to rats eat 26 weeks time, just cause weight loss, did not cause internal symptoms. And with the uncured resin mixture in food Epon828 (5% or so), after 26 weeks feeding, increase the number of mice died. So that completely cured epoxy resin (bisphenol-A) is non-toxic. However, if curing is not entirely a different matter.