WO1994005765A1

WO1994005765A1 - Cleaning-fluid composition

Info

Publication number: WO1994005765A1
Application number: PCT/DE1993/000694
Authority: WO
Inventors: Jürgen Dötsch
Original assignee: Chemie X 2000 Schrupstock Gmbh & Co. Kg
Priority date: 1992-08-27
Filing date: 1993-08-06
Publication date: 1994-03-17
Also published as: DE4228461C1

Abstract

The invention concerns a cleaning-fluid composition, in particular a composition for cleaning precision-mechanical parts, electronic components and circuit boards, as well as textiles, plus a method of producing the composition and its use for the purposes stated above.

Description

Reinigunσsmediiimgi.KaTOmensetzunα

The present invention relates to a cleaning medium composition, and in particular to a cleaning medium composition for cleaning fine mechanical parts, electronic components and printed circuit boards as well as textiles, as well as a method for their production and their use for the aforementioned purposes.

Cleaning agents for the electronics and precision engineering industries are widely known in the prior art. In the

In the electronics industry, especially halogenated hydrocarbons, in particular chlorinated hydrocarbons and fluorochlorinated hydrocarbons (hereinafter referred to as CHCs and CFCs) are used. The halogenated hydrocarbons have a number of advantages due to their excellent cleaning action for certain applications. They dissolve practically all fats and waxes, even flux and rosin can be removed at normal temperature. In most cases, heating the substrate to be cleaned is just as unnecessary as a subsequent rinsing process with pure water. The cleaning process itself runs in very short periods of time. Due to the rapid evaporation of the halogenated hydrocarbons, the cleaned parts dry immediately with practically no external energy supply.

The many advantages of halogenated hydrocarbons are the only, but all decisive, disadvantage of extreme environmental hazards. On the one hand, they have a high ozone depletion potential, which means that their use due to legal measures to protect the ozone layer will be severely restricted in the next few years and will already be prohibited in some countries, on the other hand, CFCs and especially CHCs have a high water hazard potential.

Unlike other solvents such as alcohol or Acetone penetrates concrete floors themselves and can get into the groundwater.

Various possible solutions have been proposed in the prior art as alternatives to eliminating the above disadvantages.

With plasma technology as an environmentally compatible alternative, the parts to be cleaned are exposed to low-pressure plasma. The plasma itself is created by the action of microwave radiation on a certain process gas. For cleaning, oxygen, hydrogen and argon are used depending on the material of the parts to be cleaned.

The plasma reacts at relatively low temperatures in the range of 50 to 100 ° C with the fat or oil of the contaminated parts and brings these substances into the gas phase. These oxidative processes completely remove oil and grease films, and the part surfaces are cleaned right down to the molecular structures. However, this method has the disadvantage that it can only be used with slightly dirty mass parts with a uniform

Pollution degree can be applied. In certain cases, pre-cleaning with aqueous cleaners is necessary. Another disadvantage of this method is that the plasma chamber has to be charged separately for each cleaning process and, in the case of aqueous pre-cleaning, the plasma cleaning can only be carried out in an inert gas atmosphere. This results in cycle times that preclude the economical use of this process for many industrial sectors. In addition, there are the enormous investment costs, so that such a procedure is currently not sustainable for smaller companies.

Terpen-based cleaning agents have also been proposed as a replacement for the HKW. Due to their structure, which is close to that of aromatic hydrocarbons, natural terpenes are good solvents for fats, oils and resins and especially for those known as rosin summarized terpene resins. Rosin usually forms the basis of the soldering flux used in the electronics industry. However, the terpenes have the disadvantage of evaporating only very slowly from the cleaned workpieces due to their high boiling point. On the other hand, there is a difficulty in separating the high-boiling terpenes from the solutes by distillation. For this reason, the terpenes often have to be rinsed off with a different medium from the cleaned workpieces. Although water is suitable as a rinsing medium, the addition of an emulsifier and a

Rinsing step required and the water-wet workpieces require a relatively high amount of drying. In addition, in the case of semi-open structures, the solvent cannot be removed or can only be removed with difficulty due to a lack of flushing. Also require cleaning facilities that contain terpene

Solvents are used, an increased outlay on equipment, since precautions for explosion protection must be taken. In addition, many terpene-based cleaners, due to their skin-toxic properties, cause skin diseases such as skin scabies in workers, and such cleaners are therefore prohibited in the United States, for example.

The use of cleaning agents containing isopropyl as a substitute for HKW has also been proposed. However, these cleaning agents have the disadvantage that isopropanol has only a limited ability to dissolve greasy or wax-like impurities, and on the other hand the use of isopropyl alcohol due to its low flash point means that the cleaning systems are equipped with special agents to ensure fire safety.

The object of the invention is now to provide a novel cleaning medium composition which has excellent solvent properties for contaminants, for example in the case of fine mechanical or electronic Construction, possesses and at the same time requires little equipment for the cleaning systems, brings with it a low environmental impact and is easy and safe to use.

The inventors have now surprisingly found that the object of the invention is achieved by providing a cleaning medium composition which comprises a) 0.001 to 10% by weight, preferably 1 to 5% by weight, of a cyclic, straight-chain or branched aliphatic hydrocarbon with 5 to 15, preferably 6 to 8 carbon atoms, the hydrocarbon containing at least one alkenyl and / or alkynyl unit in the molecule and at least one hydroxyl group in the molecule and having a boiling point in the range from 50 to 200 ° C. at 1.013 × 10 ⁵ Pa, b) 5 up to 60% by weight, preferably 5 to 40% by weight, of a cyclic derivative of an aliphatic carboxylic acid with 5 or 6 ring atoms, which can be substituted by one or more alkyl groups with 1 to 6 carbon atoms, c) 10 to 70% by weight, preferably 30 to 65% by weight of one or more compounds of the formula (I)

R ^ CHOH-CH - (- 0-CHR ³ -CH ₂ -) _n -0R ² (I) in which R ¹ and R ³ , which may be the same or different, denote hydrogen, methyl or ethyl,

R ^{2 stands} for hydrogen or an alkyl group with 1-4 carbon atoms and n stands for a number of 0 or 1, the sum of the individual components a), b), and c) 100% by weight, based on the weight of the overall composition , is.

The composition according to the invention has excellent solvent properties for the contamination occurring in electronic or precision mechanical components. On the one hand, they are partially contained in the soldering flux

Rosin and its substitutes excellently solved, for others, boards or similar components which are already in use and which have been removed in the course of maintenance work, can easily be freed from contaminants such as dust, grease, inorganic particles and other organic contaminants.

Because of its formulation, the composition according to the invention has the advantage that, on the one hand, it has surfactant properties, but on the other hand it also has solvent properties that are close to pure solvents. So the solvency of the invention

Formulation beyond the capabilities of the HKW used so far. The effect of HKW and also the hydrocarbons that are sometimes proposed as substitutes for HKW is based exclusively on the dissolving of impurities, i.e. all impurities on the substrate that are soluble in the applied medium are removed from the surface. For this reason, the aforementioned solvents were mainly used to remove organic contaminants. Inorganic contaminants that are insoluble in the solvents, such as pigments, metal debris, chips, rust and cover layers have not been removed.

In contrast, such impurities and particles can be removed when using the formulation according to the invention. At the same time, the formulation according to the invention has the advantage that all of the components it contains are volatile and, if appropriate with a slight supply of heat, evaporate more or less rapidly, depending on the composition. It is thus possible to first treat the workpiece to be cleaned with the formulation according to the invention, to rinse it with the formulation according to the invention in a second step and then to dry the substrate in a third step. There are no intermediate rinsing steps with water and / or other solvents before the drying process. Drying, if the treated substrate permits, can increase the rate of evaporation in addition to the supply of heat and also by lowering the gas pressure in the environment in which the substrate is ready for drying, can be accelerated. In addition, the formulation according to the invention has the advantage that the components contained in it are all biodegradable. The cleaning medium composition according to the invention contains as component a) 0.001 to 10% by weight, preferably 1 to 5% by weight, of a cyclic, straight-chain or branched aliphatic hydrocarbon having 5 to 15, preferably 6 to 8 carbon atoms, the hydrocarbon at least one alkenyl and / or contains alkynyl unit in the molecule and at least one hydroxyl group in the molecule and has a boiling point in the range from 50 to 200 ° C. at 1.013 × 10 ⁵ Pa.

If the boiling point of the component is above 200 ° C, drying times for the cleaned substrate are too long. If the boiling point is below 50 ^° C, the flash point of the hydrocarbon drops so much that safe handling of the cleaning medium composition is made difficult and additional measures in the area of fire safety are required. The boiling point of that used as component a)

Hydrocarbon is related to the degree of branching and the number of carbon atoms, as well as the number of hydroxyl groups and unsaturation in the molecule. Since component a) is essentially responsible for the surfactant properties of the composition according to the invention, the person skilled in the art can easily select the compounds which meet the conditions with regard to the number of carbon, boiling point and number of unsaturations and hydroxyl groups in the molecule. The surfactant properties of component a) depend mainly on the numerical ratio of the hydrophilic groups to the hydrophobic groups and the length of the hydrophobic chain to the number of hydrophilic groups. Other factors are the number of carbon atoms, the degree of branching and the number of unsaturations in the

Molecule. The boiling point is strongest from the number the hydroxyl groups affected.

The surfactant properties of component a) are desirable in order to facilitate the wetting of the oily and greasy soiling to be removed, and lead to an increase in the dissolution rate due to the creeping action. Component a) preferably contains only one hydroxyl group, which is preferably terminal or in the 2- or 3-position.

Component a) preferably contains an unsaturation (alkenyl / alkynyl) which is preferably terminal.

Examples of compounds a) are 3-hydroxy-l-pentin, 3,4-dimethyl-3-hydroxy-l-pentin, 3-methyl-3-hydroxy-l-pentin, 3-methyl-3-hydroxy-l- hexyne, 3-hydroxy-1-hexene, 2-methyl-4-hydroxy-1-heptene, 3,5-dimethyl-3-hydroxy-1-hexyne, 3-methyl-3-hydroxy-1-octyne.

The use of 3,5-dimethyl-3-hydroxy-1-hexyne is particularly preferred. This compound is commercially available under the name Surfynol 61 (trademark of Air Products). Because such connections that have a terminal

Having unsaturation, compared to the corresponding compounds which have a non-terminal unsaturation and a lower boiling point, terminal unsaturation is preferred in compounds a).

5 to 60% by weight, preferably 5 to 40% by weight, of a cyclic derivative of an aliphatic carboxylic acid having 5 or 6 ring atoms, which can be substituted by one or more alkyl groups having 1 to 6 carbon atoms, are used as component b of the cleaning medium composition according to the invention , used. Lactams and lactones are understood here as cyclic derivatives of an aliphatic carboxylic acid for the purposes of the invention. Examples of the compounds which can be used according to the invention as component b) are γ-butyrolactone, N-methyl-γ-butyrolactam, δ-valerolactone and δ-valerolactam and their alkyl-substituted derivatives. The use of N-methyl-butyrolactam, also called N-methyl-pyrrolidone, is particularly preferred. Γ-Valerolactone can also be used.

Component b) serves as an inert, stable and polar aprotic solvent for a number of compounds and mainly for dissolving resins such as rosin and also as an auxiliary solvent and cleaning enhancer for oils and fats. When using N-methyl-pyrrolidone, a weakly swelling influence on the treated substrate can sometimes be observed, which is not disturbing and can also be desirable at times.

At the same time, component b) enables the preparation of a homogeneous solution of the composition according to the invention as a solubilizer, in particular if the composition contains water. In any case, the

Component b) can be evaporated under the drying conditions, if appropriate with the addition of heat.

As component c) of the composition according to the invention, 10 to 70% by weight, preferably 30 to 65% by weight, of one or more compounds of the formula (I) are used, R ^x -CHOH-CH ₂ - (- 0-CHR ³ -CH ₂ -) _n -0R ² (I) in which R ¹ and R ³ , which may be the same or different, denote hydrogen, methyl or ethyl, R ^{2 represents} hydrogen or an alkyl group having 1-4 carbon atoms and n represents a number from 0 or 1. The compounds of formula (I) are monoalkyl ethers of ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol as well as mixed propylene-ethylene glycols. Examples are given here

Ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol methol ether, propylene glycol n-butyl ether and ethylene glycol n-butyl ether. Such propylene glycol ethers are commercially available, for example, under the Dowanol trademark from Dow Chemicals. Depending on the intended use and the substrate to be cleaned the compounds used as component c) can be adapted to the required dissolving properties for the impurities by varying the alkyl radical of the ether unit and adapting the molecular size in relation to lipophilicity or hydrophilicity.

Component c) serves as a solubilizer for the water-insoluble contaminants and acts as an auxiliary solvent for greasy contaminants.

It is particularly preferred to use mixtures of several compounds c) which are of the general formula

(I) fall. By a suitable choice of the different compounds c) with the formula (I), the person skilled in the art can select a wide range of solutions for a large number of compounds.

In any case, the compounds used as component c) must have a boiling point which allows these compounds to evaporate within an acceptable period of time, possibly with the addition of heat. The boiling point of the compounds of components c should therefore not be above 250 ° C., preferably not above 200 ° C., at 1.013 × 10 ⁵ Pa (atmospheric pressure).

The lipophilic character is enhanced by a larger proportion of short-chain propylene glycol or ethylene glycol ethers, whereas the dimeric ethylene glycol ethers or propylene glycol ethers impart a stronger hydrophilic proportion to the composition.

In a particular embodiment of the composition according to the invention, if mono- or dipropylene glycol compounds are used as component c), an ethylene glycol monoalkyl ether can additionally be present as component d) with up to 12% by weight, preferably up to 8% by weight, particularly preferably up to 5% by weight, with the formula (II)

R ⁴ -0-CH ₂ -CH ₂ -0H (II),

wherein R ^{4 represents} a straight-chain or branched alkyl group having 1 to 6, preferably 2 to 5 carbon atoms, the The sum of the individual components is 100% by weight, based on the weight of the total composition, and the compounds of the formula (I) and of the formula (II) are different. The additional use of this compound d) improves the solvent properties of the composition according to the invention.

Examples of compounds which can be used as component d) are ethoxyethanol, propoxyethanol, iso-propoxyethanol, n-butoxyethanol and 2-butoxyethanol. The use of n-butoxyethanol is particularly preferred.

In any case, component d) must be a different compound than component c).

If the surface of the substrate to be treated is not impaired by contact with water, the composition according to the invention can also contain up to 30% by weight, preferably up to 15% by weight, of water. The addition of water increases the hydrophilicity of the mixture and ensures that dirt particles are easily dispersible in the cleaning solution. Such a water-containing solution is well suited for cleaning printed circuit boards.

In a further embodiment, the composition according to the invention can additionally contain up to 20% by weight, preferably up to 10% by weight, of a lower aliphatic alcohol having 1 to 6 carbon atoms. The addition of the alcohol serves to increase the rate of evaporation due to azeotrope formation during the evaporation of the cleaning medium composition according to the invention. Examples of the alcohols that can be used are here

Ethanol, propanol, isopropanol, butyl alcohol, isobutyl alcohol, pentanol, cyclopentanol, hexanol and cyclohexanol. Isopropyl alcohol is preferred. Instead of a single alcohol, it is also possible to use mixtures of different alcohols which meet the aforementioned condition. To produce the cleaning medium composition according to the invention, the individual components, which are in liquid form at room temperature, are combined in the proportions covered by the claim formulations and intimately mixed with one another. The compositions thus produced are ready for immediate use.

For cleaning printed circuit boards, the cleaning medium compositions according to the invention thus produced can be used undiluted like a pure solvent. The substrates to be cleaned are immersed in the cleaning solution and optionally pre-cleaned with mechanical support, for example by ultrasound treatment. In a next step, the substrates are rinsed with a second cleaning solution and dried with hot air after drying.

If the first detergent solution is used up due to a high absorption of impurities, the detergent solution used for rinsing in the second cleaning step can be used instead of the first for cleaning and a fresh detergent solution instead of the second for rinsing, so that a high utilization of the solution is ensured and the consumption of detergent is reduced. If the substrate surface is not sensitive to water, cleaning can be carried out with a dilute aqueous solution of the cleaning medium composition. For this purpose, the substrate is prewashed with a 5 to 15% solution, if necessary with mechanical support by means of ultrasound, flooding, spraying and / or

Heat input, then rinsed with the same solution and dried with hot air after draining. With this cleaning, the rinsing bath in cascades can later be used as the actual cleaning bath. When cleaning printed circuit boards in this way, any residues of detergent composition are removed Blowing out of blind holes and cracks easily expelled, since a typical capillary effect as with conventional surfactants is not observed. The soldered components remain intact in this process, and the used cleaning baths can easily be freed from the impurities, for example by evaporation, and reprocessed.

To clean fine mechanical components, a cleaning medium composition according to the invention without water content is generally used in order to prevent a risk of corrosion. Preventing corrosion is particularly important for the reason that metal surfaces of these components are machined to within a few micrometers and often seal without additional seals, e.g. in brake systems such as brake calipers, ABS devices for motor vehicles. The function of these components can thus be particularly easily impaired by corrosion.

These components are optionally cleaned with mechanical support in the undiluted cleaning composition according to the invention and rinsed and dried in a second cleaning step with the cleaning composition. Soiling such as machining oils, abrasives, anti-corrosion agents and brake fluids are easily removed, and pigment soiling such as e.g. Lapping agent removed. The degreasing of the metallic surfaces is so extensive that fittings for oxygen and microswitches, which serve as safety switches, can be reliably degreased with the cleaning medium composition according to the invention. Even surfaces of plastics that do not

Interactions with the components of the cleaning composition can be reliably degreased in this way.

It is also possible to pre-clean the precision mechanical components with the cleaning composition in a pre-cleaning step, and the pre-cleaned substrates, one have a small, relatively evenly distributed residual amount of cleaning composition on the surface, then subject to plasma cleaning without a drying step. The cleaning composition according to the invention is also suitable for removing underbody protection and / or paints that are not or only partially polymerized. To do this, the cleaning composition can simply be placed on a wipe, and then the excess polymer residues are dissolved and wiped off the surface. It is also possible to use the invention

Use cleaning medium composition as a substitute for the halogenated hydrocarbons previously used in the cleaning of textile fabrics. The textiles are immersed in appropriate baths which contain the cleaning composition according to the invention, preferably in undiluted form, and are left in the baths for a while, if necessary with mechanical support. The length of time the textiles are left in the baths depends on the degree of soiling and can last from a few minutes to several hours. Of course, a short exposure time is economical in view of the short cycle times of the cleaning system. The textiles to be cleaned can consist of the materials which are usually cleaned in conventional cleaning systems in which halogenated hydrocarbons are used and generally show No impairments or interactions due to the treatment with the cleaning composition according to the invention, except for those fabrics which consist partly or entirely of polyester and which swell or dissolve completely in the cleaning composition.

However, the person skilled in the art can determine by simple preliminary tests which textile fabrics are suitable for treatment with the cleaning composition according to the invention.

In all of the cleaning processes mentioned above, the drying process can advantageously be accelerated in that the cleaned substrate, which after cleaning and / or Rinse off a thin film from the

Can have cleaning composition on the surface, is introduced into a corresponding chamber, in which the internal pressure is reduced and the evaporation is accelerated. Depending on the suitability of the substrate, the pressure can be reduced to a value of a few hundred Pa, effectively speeding up drying.

In all cleaning processes, the decisive advantages of the cleaning medium composition according to the invention over the formulations known from the prior art are the residue-free vaporizability of the cleaning composition without intermediate rinsing steps with other solvents, including water, and the biodegradability of the individual components.

Claims

1. cleaning medium composition, characterized in that the composition comprises:

a) 0.001 to 10 wt.%, preferably 1 to 5 wt.%, of a cyclic, straight-chain or branched aliphatic hydrocarbon having 5 to 15, preferably 6 to 8 carbon atoms, the hydrocarbon at least one alkenyl and / or alkynyl unit in the molecule and contains at least one hydroxyl group in the molecule and has a boiling point in the range from 50 to 200 ° C at 1.013 x 10 ⁵ Pa,

b) 5 to 60% by weight, preferably 5 to 40% by weight, of a cyclic derivative of an aliphatic carboxylic acid with 5 or 6 ring atoms, which can be substituted by one or more alkyl groups with 1 to 6 carbon atoms,

c) 10 to 70% by weight, preferably 30 to 65% by weight, of one or more compounds of the formula (I)

R ^ CHOH-CH _, - (- 0-CHR ³ -CH ₂ -) _n -0R ² (I) in which R ¹ and R ³ , which may be the same or different, denote hydrogen, methyl or ethyl,

R ^{2 represents} hydrogen or an alkyl group with 1-4 carbon atoms and n stands for a number of 0 or 1, the sum of the individual components a), b) and c) being 100% by weight, based on the weight of the total composition.

2. Cleaning medium composition according to claim 1, characterized in that it additionally d) up to 12 wt.%, Preferably up to 8 wt.%, Particularly preferably up to 5 wt.%, Of a compound of formula (II)

R ^{4 contains} -0-CH ₂ -CH ₂ -0H (II), wherein R ^{4 represents} a straight-chain or branched

Alkyl group with 1 to 6, preferably 2 to 5 carbon atoms is, the sum of the individual components is 100% by weight, based on the weight of the total composition, and the compounds of the formula (I) and of the formula (II) are different.

3. cleaning medium composition according to claim 1 or 2, characterized in that it additionally contains up to 30% by weight, preferably up to 15% by weight, water, the sum of the individual components being 100% by weight, based on the weight of the total composition.

4. Cleaning medium composition according to one of claims 1 to 3, characterized in that it additionally contains up to 20% by weight, preferably up to 10% by weight, of a lower, cyclic, straight-chain or branched aliphatic

Contains alcohol with 1 to 6 carbon atoms, the sum of the individual components is 100% by weight, based on the weight of the entire composition.

5. Cleaning medium composition according to one of the

Claims 1 to 4, characterized in that a straight-chain or branched aliphatic hydrocarbon having 7 to 11 carbon atoms is used as component a), the hydrocarbon containing at least one alkynyl unit in the molecule and at least one hydroxyl group in the molecule and a boiling point in the range from 50 to 200 ° C at 1.013 x 10 ^s Pa.

6. Cleaning medium composition according to claim 5, characterized in that 3,5-dimethyl-l-hexin-3-ol is used as component a).

7. cleaning medium composition according to any one of claims 1 to 6, characterized in that as component b) a cyclic derivative of an aliphatic carboxylic acid with 5 ring atoms, which by one or more alkyl groups with 1 to 6 carbon atoms can be used.

8. cleaning medium composition according to one of claims 1 to 7, characterized in that as component c) a mixture of at least two different compounds of formula (I)

R ^ CHOH-CH, - (- 0-CHR ³ -CH ₂ -) _n -0R ² (I) is used, wherein for a first compound R ^{1 is} methyl, R ² for an alkyl group with 1-4 carbon atoms and n stand for the number 0, and being for a second

Compound R ¹ and R ^{3 are} methyl, R ^{2 is} an alkyl group with 1-4 carbon atoms and n is the number 1.

9. Process for the preparation of the cleaning medium composition according to one of claims 1 to 8, characterized in that the individual components are mixed with one another in such proportions that an essentially clear solution results.

10. Use of the cleaning medium composition according to one of claims 1 to 8 for cleaning fine mechanical parts, electronic components and printed circuit boards.

11. Use of the cleaning medium composition according to one of claims 1 to 8 for the removal of non or partially polymerized underbody protection and paints in the automotive industry.

12. Use of the cleaning medium composition according to one of claims 1 to 8 for cleaning textile fabrics.