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Full release type indoor fumigation agent

Full release type indoor fumigation agent

2015-06-25

First full release type indoor fumigation agent
I. overview
Around 1958, according to Thomas Donaldson's idea to develop this quite unique aerosol products. The basic concept of the product is a one-time full content of the aerosol release into the room or small unit, the fine mist particles may be permeated the regional, if the words of any openings in the wall. It can even infiltrated between the walls, thereby killing them in contact each insect. To guide the user closed all the doors and windows, close all ventilation, open the cabinet doors and drawer, the aerosol in the shop on the paper chair or table, after the start of the nozzle immediately left the scene, and, at least in the 2H (4h) do not enter the spray.
Fumigant borrow almost vertical upwardly toward the ceiling of the fog column play a role, the tank will continue to spray a few minutes, until the whole spray cans until the end, spewing out of the fog is very large quantities of air dilution and spread to the room or unit, its exposure to every insect killing. In many times, less than lethal concentration of fog will penetrate into the hidden crawler dark holes, cracks, corner, poison fog agent will strongly stimulate the insects and make them leave the hidden drug place of ran into the office, here the insecticide liquid concentration high enough to kill them.
Early release type indoor fumigation agent with great efficiency of pyrethrum prime cytotoxic agents based, add some propyl alcohol to prevent when using spray hole frost and the influence of the fog to the jetting direction, is rarely useful in essence. The rest are chlorofluorocarbons (CFC) propellant. This is not the amount of propellant combustion can be as high as 88%, so do not have to worry about combustion products. These formulations have been used in 1978, and then in the United States to ban CFC used in aerosol. At this time, the fumigation agent in the United States has been very popular, annual sales of about 55000000 cans. After 1978, Canada, Mexico, Europe and other places still use CFC, but in the United States must use other propellant, early with CFC free formulation can see table 2-1.
Table 2-1 the United States early in the recipe (1968~1978)
Component
The content (mass fraction) /%
Component
The content (mass fraction) /%
Extract of Chrysanthemum
(20% insecticidal active ingredients)
Piperonyl butoxide (technical grade)
Essence (selection)
2.50
1
0.20
Tasteless kerosene
ISO alcohol (99%)
CFC-11
CFC-12
7.30
9
32
48
Note: pressure, 21, 56.67kPa, 0.36Mpa pressure relief valve.
After 1978, the fumigant has used different propellant, the lowest price, the most popular way is with mass fraction of 28% hydrocarbon mixture A-70 (38% propane and 62% isobutane mixture). Other formulations include the use of two 46% ether, or 32%HCFC152a and 24%HCFC-22, the other formulations are combustible. From the 1980 European toxicology report pointed out that HCFC-22 is a mutagen. Before this, HCFC-22 used more. Since then, DuPont and other suppliers refused to supply it with application of aerosol, around 1987, other toxicological studies pointed out that in any concentration of aerosol spray it is not a mutagen.
In order to reduce the product flammability concerns, marketers in fumigant formulations used a lot of nonflammable chlorinated solvents, such as about 20% dichloromethane and greater amounts of L, l, l trichloro ethane. Around 1984 and meets another trouble. In order to verify the dichloromethane is mutagens or carcinogens, it is like similar to that of carbon tetrachloride, chloroform, and vinyl chloride monomer (CH2==CHCL) such as chlorine solvent that undergo each possible toxicological experiment, finally by tube feeding method will be 90% lethal amount of liquid dichloromethane daily infusion into sensitive to cancer of rat stomach. For several months, some survival rat appeared liver tumor. However, these are not cancer. The official explanation for this is that the discovery could prove to be an animal carcinogen.
This may also be a human carcinogen. Later, Dow Chemical Company and other studies show that, although the dichloromethane can cause damage, but not a carcinogen or mutagen. In spite of this, the United States Department of environment still refuses to register with the pesticide products containing the solvent.
The industry had to remove methylene chloride, only 1, 1, three 1- ethylene chloride to replace it. Used to generate three chloride after the fog thicker than the original, so must use a little more hydrocarbon or other propellant. See table 2-2 for this type of product formulation.
Table 2-1 the United States early in the recipe (1968~1978)
Component
The mass fraction of /%
Component
The mass fraction of /%
Pyrethrum extract
(20% insecticidal active ingredients)
Piperonyl butoxide (technical grade)
Essence (selection)
Tasteless kerosene
2.50
1
0.20
7.50
ISO alcohol (99%)
1, 1, 1, - three
Mixed hydrocarbon propellant (A-70 or A-85)
4.80
54
30
Note: pressure, 21, 66.67kPa, 0.41MPa pressure relief valve.
In 1988, an atmospheric scientist announced that in addition to CFCs and many substances can consume the earth's stratospheric ozone layer. These substances include carbon tetrachloride, methyl bromide (CH3Br), Hanlon (cf3br), HCFCs (CHCIF2) and trichloro ethane, the last one compound trichloroethane deplete the ozone layer is about 12% of CFC-11. In the second half of 1990, the Congress of the United States through the "essence of air regulations amendment", directed the U. S. environmental agency confirmed loss activity of trichloroethane, then disable it had been widely used solvent ban in 1994 effect. This is in fact a step by step implementation of the ban, but in fact, the immediate and complete ban on the use of three chlorine gas aerosol products

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