Handbook of Solvents - George Wypych - ChemTech - Ventech!

1498 Kaspar D. Hasenclever
in accordance to the national regulations (in Germany Druckbehälter Verordnung certification).
Tanks and/or containers for LCD have three to four times the weight of their net capacity.
21.4.1.2 State of the art
The stability of textiles, textile dyes, buttons, zips, interlinings under influence of high pressure
in LCD and ScCD was tested at DTNW, Krefeld, DWI/TH Aachen. Both, LCD and
ScCD, if they are pure, do not harm textiles and dyes. After treatment in ScCD buttons and
plastic zips are destroyed, when the decompression of CO2 runs fast.
LCD and ScCD are able to penetrate into apolar polymers such as polyester and
polyamide, and plasticize the material so that dispersed substances can migrate into them.
This behavior is used for dyeing processes with dispersion dyestuffs in ScCD, which allows
textile dyeing without waste. The same procedure can cause greying in drycleaning, if resolved
pigments are dispersed in LCD cleaning fluids.
In Journal of Supercritical Fluids, (1990), 3, 51-65 Consani and Smith of Battelle Pacific
Northwest Laboratories report the Observation on the Solubility of Surfactants and Related
Molecules in Carbon Dioxide at 50°C. Nearly all known surfactants are classified.
In US patent 5,467,492 Hughes Aircraft Company claims a dry cleaning in LCD with
the distinguishing feature of a non moving basket together with jet agitation to the load by
current circulation of the LCD cleaning fluid. In order to reach this aim, the pressure vessel
contains a cylindrical perforated basket to take the load. After the pressure vessel is totally
filled with LCD, the load is then set into motion and agitated by high velocity fluid jets. A
dry cleaning machine presented at Las Vegas in 1997 was equipped with a 135 l pressure
cylinder and the capability to clean a load of textiles of about 10 kg.
At the same exhibition Miccel, Technologies, Inc.; North Carolina State University
presented the MiCARE Garment Cleaning Fluid System, which consists of LCD together
with patented surfactants as cleaning fluid and a dry cleaning machine for LCD, equipped
with a moving basket, creating agitation in the conventional manner.
In Science, Feb. 1996, E. Goldbaum published a report on the development of a team
of scientists of the University of Texas, the University of Nottingham and the University of
Colorado, using water in CO2 microemulsions with fluorinated surfactants in place of conventional
solvents, such as chlorinated hydrocarbons or hydrocarbons. This research was
funded by a Department of Energy grant of the US.
The Research Institute Hohenstein together with other German Research Institutes
and industrial Partners (Kreussler) are working on a basic research project, to define the interactions
between LCD, textiles, surfactants, dissolved, emulsified and/or dispersed matter
in this system.
The Dutch Research Institute TNO, Delft works together with industrial partners on a
project to develop the complete background for textile cleaning in LCD under practical conditions.
As part of this project Kreussler is responsible for the research and development of
detergents and the cleaning process.
21.4.1.3 Process technology
Outer garments - apparel - in average of European countries contain about 15 g/kg soiling,
when they are brought to dry cleaning. This “soiling” contains:
50% pigments aerosols, carbon black, iron oxides, dust;
30% water soluble perspiration, salt, body excrements;