This invention relates to a cleaning process, more particularly it relates to a process for elimination of organic and/or mineral marks from a solid surface (or substrate).
In electrical, electronic, optical and mechanical industries in particular, it is necessary to eliminate completely the mineral and/or organic marks from pieces or materials of products that are finished or that have to undergo subsequent transformation stages.
Traditionally, these surfaces were cleaned with 1,1,1-trichloroethane, a very polyvalent solvent, but which had been condemned by the protocol of Montreal because of its impact on the ozone layer.
It is also known to use cleaning compositions that come in the form of microemulsions that are stable at ambient temperature as described in Patent Application FR 2 795 088 that exhibit the advantage of eliminating both the organic and mineral marks because they combine a solvent portion and a mineral portion.
It is necessary, however, to carry out a rinsing with water of the treated surface with said microemulsion-type compositions and, in the above-mentioned technical fields, the surfaces should be not only free of any mineral and/or organic marks but also completely rid of water.
A cleaning process that makes it possible to eliminate all organic and/or mineral marks and the traces of water from a solid surface (or substrate) has now been found, characterized in that it comprises the following stages.
The microemulsion-type cleaning composition that is used according to the invention offers the advantage of being able to eliminate effectively any organic and/or mineral marks from the solid surface that is to be cleaned.
A preferred microemulsion-type cleaning composition is described in Patent Application FR2 795 088.
It comprises in particular:
in which:
Cleaning stage a) can be carried out in an immersion tank or a shower bath in combination with ultrasonic waves, vibrations or mechanical shaking.
The microemulsion-type cleaning composition will be used at a temperature that ranges from ambient temperature (about 20° C.) to 60° C. and preferably at a temperature of between 20° C. and 40° C.
The cleaning period of the solid surface—stage a)—is based on the type of mark and its adhesion to the solid surface.
This cleaning period does not exceed 5 minutes and preferably is between 1 and 3 minutes.
Organic solvent or solvents (B) that is/are contained in the microemulsion-type cleaning composition that is used in stage a) is/are selected preferably from among the aliphatic hydrocarbons, the alkylene glycol monoethers, and the dialkylene glycol monoethers.
The aliphatic hydrocarbons can be linear, branched, or cyclic hydrocarbons or combinations thereof. They contain in particular 3 to 24 carbon atoms, preferably 6 to 24 carbon atoms. Examples of aliphatic hydrocarbons that are commercially available are:
The monoethers of alkylene glycols can be in particular propylene glycol monoethers of C4-C25, such as propylene glycol monomethyl ether (PM), propylene glycol monoethyl ether (PR). propylene glycol mono-n-propyl ether (PNP), propylene glycol mono-tert-butyl ether (PTB), propylene glycol mono-n-butyl ether (PNB), and propylene glycol mono-hexyl ether.
The dialkylene glycol monoethers can be, for example, dipropylene glycol monomethyl ether (DPM), dipropylene glycol mono-n-propyl ether (DPNP), dipropylene glycol mono-tert-butyl ether (DPTB), dipropylene glycol mono-n-butyl ether (DPNB), and dipropylene glycol monohexyl ether; and diethylene glycol n-butyl ether (butyl diglycol ether-BDG), diethylene glyco) hexyl ether and diethylene glycol octyl ether.
The composition that can be used according to the invention can also contain:
The cleaned solid surface is subjected to a draining stage b) that consists in withdrawing said cleaned solid surface from the cleaning composition and in draining it at ambient temperature for a period that ranges from 30 seconds to 1 minute.
Finally, the drained solid surface is subjected to a rinsing stage c) that is carried out with an organic solvent or a mixture of organic solvents, inert, preferably non-inflammable and with a low boiling point.
This rinsing stage is carried out at a temperature that is less than 10 to 15° C., preferably less than 5° C., of the boiling point of the organic solvent or the most volatile compound from the mixture of organic solvents used for said rinsing stage.
Concerning mixtures of organic solvents, most particularly azeotropic mixtures or quasi-azeotropic mixtures will be used.
Organic solvent or a mixture of organic solvents of a low boiling point is currently defined as an organic solvent or a mixture of organic solvents that have a boiling point that is at most equal to 90° C. and preferably between 25° C. and 70° C.
The organic solvent or the mixture of organic solvents can be selected in particular from among:
Azeotropic mixtures or quasi-azeotropic mixtures of at least two of the above-mentioned compounds will be used.
By way of illustration of such azeotropic or quasi-azeotropic mixtures that can be used according to this invention as rinsing solvents, there will be cited:
Among all of these azeotropic mixtures most particularly preferred are the ternary azeotrope 4310 mee/365 mfc/CH3OH (12, 83, 5), the binary azeotrope 4310 mee/(CH2Cl2 (50/50), the binary azeotrope 365 mfc/CH2Cl2 (56.6/43.4), the binary azeotrope 4310 mee/365 mfc (9/91), the ternary quasi-azeotrope 365 mfc/CH2Cl2/CH3OH (89/7/4), the binary azeotrope 141b/methanol (96/4), and the ternary azeotrope 365/CH2Cl2/CH3OH (57/39.5/3.5).
According to this invention, drying surge d) is carried out by exposing the rinsed solid surface to the vapor that is produced by heating the organic solvent or the mixture of organic solvents used in rinsing stage c). In the case of a mixture of non-azeotropic, solvents, the rinsed surface will be dried by the vapor of the most volatile compound.
The drying period is at least 20 seconds and preferably between 30 seconds and 1 minutes
The process according to this invention pertains most particularly to the elimination of organic and/or mineral marks from the solid surfaces of metal pieces, ceramic pieces, glass pieces, plastic pieces, or printed circuits (electronic pieces, pieces of semi-conductors).
The process of this invention makes it possible to obtain clean solid surfaces that are free of any organic and/or mineral marks as well as traces of water. The pieces that are cleaned by means of the process according to the invention can be used immediately for other treatment operations, such as, for example, painting or electrodeposition.
The device for implementing the process according to the invention can consist of the sequence or the following devices:
The rinsing-drying stages are preferably carried out in an industrial machine that comprises at least two tanks that are provided with means for heating and condensation.
In a first tank, optionally equipped with means for ultrasound production, the rinsing of the piece is carried out by its immersion in a bath of organic solvent or a mixture of organic solvents that is brought to a temperature as defined above. Next, the piece is withdrawn from said bath and then conveyed to the second tank to be dried there. This second tank contains the organic solvent or the mixture of organic solvents that are used in the preceding rinsing tank that is brought to its boiling point.
The piece is therefore dried by the vapors of the organic solvent or the mixture of organic solvents that are used for the rinsing. These vapors are condensed by means of a condensation coil that is cooled and recycled in the liquid rinsing tank.
The following examples illustrate the invention.
Equipment:
Placed in a line are:
The diagram of the sequence is as follows:
Pieces to be Cleaned:
These plates and the grid are placed on a basket that carries out the sequence above.
Products that are Used:
The cleaning sequence is carried out according to the diagram above on the plates and the grid that are coated by the marks mentioned above. The bath temperature of the cleaning tank is 40° C.
The rinsing temperature is equal to Te-5° C., whereby Te is the boiling point of the organic solvent, the azeotrope or else the quasi-azeotrope.
The results are recorded in Table 1.
Number | Date | Country | Kind |
---|---|---|---|
01 00228 | Jan 2001 | FR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/FR02/00035 | 1/7/2002 | WO | 00 | 12/29/2003 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO02/055223 | 7/18/2002 | WO | A |
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