Study On The Paint Dissolution Efficiency,Explosion Hazard And Environmental Toxicity Of Main Components Of Nitrocellulose Lacquer Thinner And Their Mixtures

Nitrocellulose lacquer thinner,a colorless,transparent,flammable and volatile mixed organic solution with strong odor,is widely used in the painting,paint removal and cleaning processes of furniture,decoration and automobile industries.Safety accidents caused by nitrocellulose lacquer thinners are pretty common.In addition,accidents of this type of organic solvents that cause a large number of leaks during transportation,which affect the environment,also occur from time to time.Nitrocellulose lacquer thinner is mainly composed of three types of solvents: true solvent,co-solvent and non-solvent.Among them,the true solvent refers to a solvent that can directly dissolve nitrocellulose,mainly esters and ketones.Cosolvent cannot directly dissolve nitrocellulose by itself,but can promote the dissolution of nitrocellulose when used together with a true solvent.The non-solvent refers to the solvent added to dissolve other components such as resin.The research objects of this article are 6 kinds of true solvents(methyl acetate,ethyl acetate,n-propyl acetate,butyl acetate,ethyl propionate and ethyl butyrate),3 kinds of cosolvents(ethyl alcohol,isopropanol and isobutyl Alcohol)and 3 kinds of non-solvents(nhexane,n-heptane and petroleum ether).We investigated the paint removal efficiency,explosion hazard and environmental impact of nitrocellulose lacquer thinner,through the curing paint film dissolution experiment,the lower explosion limit test and the algae growth inhibition experiment.And solvents with higher paint removal efficiency,relatively small explosion risk and relatively small environmental impact are selected from them.The conclusions of this article are as follows:(1)From the perspective of the efficiency of dissolving paint,methyl acetate is a better true solvent(39.64mg/min)in the comparison experiment of true solvents.In the comparison experiment of cosolvent,ethyl alcohol is better than the other two co-solvents,because the promotion effect is more obvious.When the concentration of the co-solvent is lower(the content is 20%),the effect of the co-solvent is better.In the non-solvent comparison experiment,the dissolving efficiency of the mixed solution composed of the three non-solvents on the cured nitro paint film is relatively close,but in general,the effect of n-hexane is better.(2)From the perspective of explosion hazard,in the comparison experiment of true solvents,methyl acetate has a higher lower explosion limit(3.17%),so methyl acetate is a safer true solvent.In the co-solvent comparison experiment,the increase in the content of ethanol helps to increase the lower explosive limit of the mixed solvent,so ethyl alcohol is a safer co-solvent.In the non-solvent comparison experiment,when the non-solvent concentration is low(for example,when the volume ratio of true solvent-cosolvent-nonsolvent is 4:1:1),the lower explosive limit of the mixed solvent containing n-hexane or petroleum ether is higher.n-heptane and petroleum ether are safer non-solvents at low concentrations.(3)From the perspective of environmental toxicity,in the comparison experiment of true solvent,methyl acetate has a higher IC50 value(20.47g/L),so methyl acetate is a less toxic true solvent.In the comparison experiment of cosolvents,mixed solvents containing ethyl alcohol or isopropyl alcohol have a higher IC50 value to algae,so ethyl alcohol and isopropyl alcohol are relatively less toxic cosolvents.In the comparison experiment of non-solvent,the mixed solvent containing n-heptane has a higher IC50 value to algae than the mixed solvent containing n-hexane or petroleum ether,but the discrepancy among several non-solvents is limited.In summary,we believed that for the main components of nitrocellulose lacquer thinner,methyl acetate(true solvent),ethanol(cosolvent)and n-hexane(non-solvent)can be mixed in a 4:1:1 volume ratio.This kind of combination has higher dissolving efficiency and lower explosion risk.Although it is not a combination with less environmental toxicity,the environmental toxicity of this combination is not much different from other combinations,and it is a relatively ideal combination.