SE535484C2 - Means for removing e.g. color and use of the agent - Google Patents

Abstract

The present invention relates to a means for removing paint, varnish, glue, rubber, plastic, soot and coke or the like on objects. The composition contains: a) aromatic alcohol with the property of being partially soluble in water, b) waterc) surfactant, andd) acid. The invention also relates to a use of the agent removal of paint etc on objects. The agent is used for removal of e.g. paint, varnish, glue, rubber, plastic, soot or coke from fixtures or objects that you wish to clean by immersion, spraying or application of a thickening composition from the same before re-use or for e.g. revision.

Description

25 30 535 484 Examples of some known solutions of the type indicated are shown, for example, in US 2007/0087952 Al, CA 2,275,304 Al and CA 2,378,886 Al. Desirable properties for a washing liquid in the aforementioned area are the following: 0 Water-based (ordinary tap water) 0 Low organic content I Low VOC 0 Surfactants with low environmental impact 0 Gentle on underlying materials and surface treatments 0 Thermally and chemically stable 0 Environmentally friendly components Further wishes for a mixture are that paint and varnish residues should not break down in the liquid as these breakdown products impair the washing effect of the liquid to the point where it is unusable. In previous systems in the alkaline side, it has been found that powder coatings are washed away in a fine powder which quickly breaks down and makes the washing liquid unusable. To minimize this degradation, it is therefore desirable that powder coatings, among other things, are washed away like a cloth to minimize the release of paint residues into the system.

The main purpose of the present invention is therefore primarily to solve, among other things, the above-mentioned problems and also to enable the simple and functional use of the agent.

Said object is achieved by means of an agent according to the present invention, which is essentially characterized in that the agent is a stable microemulsion with a water content of between 60-85% or 4-20% of the total amount that is effective in forming a microemulsion and whose content amounts to a maximum of 8% calculated on the total amount, consists of anionic or zwitterionic of the type; alkylbenzene sulfonate, alkyl sulfonate or alkylamine diproprionate, that the benzyl alcohol content is between 8-30% or 70-94% of the total amount and that the acid used as an activator (co-solvent) of the washing liquid in question consists of a weaker organic acid such as carboxylic acids such as hexanoic acid and heptanoic acid, divalent aliphatic carboxylic acids such as malonic acid and succinic acid, dihydroxy dicarboxylic acid such as tartaric acid, aromatic carboxylic acids such as benzoic acid, d-hydroxy acids such as glycolic acid and/or lactic acid or a mixture thereof.

The use of said agent for removing paint etc. from objects according to the present invention is essentially characterized by using the agent for removing e.g. paint, varnish, glue, rubber, plastic, soot or coke from fixtures or objects that one wishes to clean from the same before reuse or for e.g. reworking.

In the technology of washing liquids, according to the present invention, the molecular structure of the mixture is one of the most important parameters for increasing the effect on the washing liquid. By going from a 2-phase system with mixing to forming a microemulsion (1-phase system), the paint stripping effect on the washing liquid increases considerably. In a microemulsion, the two solvents (water and organic solvent) are not dissolved in each other but exist in different domains next to each other. The domains are so small that they do not refract light and therefore a clear solution is formed. This does not result in diluting the organic solvent with water, but the solvent still has the same concentration as if the solution had been in a 2-phase system.

Tests show that washing liquids based only on an organic solvent have a relatively low effect. By adding surfactant or acid, the washing effect of the liquid increases slightly. However, if a microemulsion is formed between solvent and water, it has been shown that the effect of the washing liquid increases considerably. These washing liquids lift the paint from the material instead of dissolving the paint. The water and the organic solvent cooperate when the paint is lifted from the material, which increases the effect. By changing the water content in the microemulsion, the washing liquid can be optimized with respect to the type of paint, application temperature, time aspects, etc.

The function of the surfactant in this technology is of different nature, where all functions are important: 0 Increase the washing effect of the washing liquid. Adding surfactant to the pure solvent increases the effect on the paint removal.

I Be able to form a microemulsion between water and organic solvent. By using a microemulsion, the effect of the washing liquid can be significantly improved. 0 Be stable for a long time at the desired temperature in order to maintain the internal structure of the washing liquid and thus obtain a sustainable washing liquid. 0 Be stable for a long time at low pH in order to maintain the internal structure of the washing liquid. 0 It must not be classified as environmentally hazardous or harmful to health. 10 15 20 25 30 535 484 According to the invention, the internal structure of the solution, i.e. the formation of a microemulsion, is an important parameter for the effect of the washing liquid. The internal structure of the solution is affected by the concentration ratio of the components in relation to each other and is therefore a very important part of the technology. It has also been shown empirically that within the concentration intervals specified there are optima for the effect of the washing liquid, which justifies the choice of the selected intervals. The aspect regarding the internal structure of the solution is not included in, for example, US 7,052,556 B1.

In the aforementioned US 7,052,556 B1, benzyl alcohol and water are used and a small amount of surfactant, xylene, 2-mercaptobenzothiazole and glycolic acid are added. The phase behavior of the mixture is not noted in the patent, but after our own experiments we know that to form a microemulsion, significantly more surfactant is needed than is used there. Xylene has also been added to this mixture, which is completely insoluble in water (but it probably dissolves in benzyl alcohol). The addition of xylene should result in the benzyl alcohol becoming even less soluble in the water phase and the probability that a microemulsion has been formed is very small.

Saqda US 7 052 556 Bl contains according to claim 3: Benzyl alcohol 50-55% Water 30-40% Sodium Lauryl sulfate 0.5-1.5% Glycolic acid 5-10% 2-Mercaptobenzothiazole 0.5-1.5% Xylene 0.1-1 o\° 10 15 20 25 30 535 484 Thus, the agent now defined according to the invention exhibits novelty in comparison with the agent shown to be previously known by US 7 052 556 Bl. Neither US 545985 A1 nor US 2005/026799 A1 discloses any agent according to the invention.

Controllable microstructure and phase separation The present invention solves several problems in a very constructive way. The invention consists of a solution consisting primarily of, but not limited to, surfactant and active water, benzyl alcohol, tor (co-solvent).

The components have such a composition that at the desired washing conditions they form a single-phase system, such as a microemulsion. The formation of a microemulsion is controlled by temperature, concentration of the components, pH and/or salt adjustments. This gives a two-phase system with a water-rich phase and a solvent-rich phase at low temperatures which, when the temperature increases, undergoes a phase transformation to a single-phase system (microemulsion). The phase transformation temperature can be controlled by changing the concentration of the components. The advantages of this are that a rational process can be achieved with economic as well as environmental benefits in the form of, among other things, the following: 0 The product can be delivered in a single-phase concentrate and diluted with tap water on site. 0 The concentration of the components can be minimized/optimized with respect to the desired washing temperature. 0 A simple analytical method for determining the content (water/solvent content) in the bath generates an 10 15 20 25 30 535 484 effective and simple conditioning of the bath during continuous use. 0 A system for cleaning and handling rinse water can be created. 0 A system for returning desired components from the rinse water to the cleaning liquid can be created. 0 A system for separating waste and used/consumed liquid into different fractions depending on energy content, water content and impurities.

Stable and rational basic mixture The main purpose of the present invention is to provide an effective and stable mixture for said cleaning purposes combined with environmental and economic benefits.

It is known that certain solvents achieve a better cleaning effect together with water, in the form of a stable microemulsion. Such a solvent must be immiscible or only partially miscible with water. One type of solvent that has been shown to have very good cleaning properties is aromatic alcohols, such as benzyl alcohol. It has been shown that an increased amount of water in the single-phase system increases the cleaning effect for many paints, varnishes, plastics, etc. Benzyl alcohol together with a limited amount of water and the other components mentioned also has a certain cleaning effect on certain systems. However, it has been shown that a microemulsion with a high water content provides an increased cleaning effect on most materials such as paint, varnish, adhesives, rubber, plastics, soot and coke. The high water concentration also reduces the solubility of any degradation products from paint, soot or coke in the mixture, which contributes to an extended service life of the washing liquid. Furthermore, a high water concentration results in improved environmental properties as well as better economic conditions for the washing liquid.

Requirements for a rational microemulsion: 0 Good penetration of the washing liquid through the material 0 The microemulsion should be stable despite the dissolution of other components. 0 The washing liquid should not dissolve residues of paint, varnish, glue, etc. but they should be held together in the leather to minimize the degradation of the washing liquid.

Microemulsions are very sensitive and phase separate easily when subjected to stress, such as washing. The aforementioned mixture, however, has proven to be very stable despite a certain admixture of, for example, paint residues. Depending on the concentration of the various components in the composition, various desirable properties can also be achieved in addition to good cleaning effect.

The composition of the components can be varied from a homogeneous mixture at room temperature, which gives products that can be used without heating (with a lower cleaning effect as a result) to mixtures that are not homogeneous at room temperature but at higher temperatures with a better and faster cleaning effect as a result. In this way, a mixture can be tailored to best suit the specific application.

The phases of the mixture are stable despite temperature changes that are above the temperature at which the microemulsion is formed. It is also possible to make a cooled mixture become homogeneous again by heating, this is independent of how many times it happens as long as the mutual relationship between the components of the mixture is stable.

This phase separation can also be utilized in the event of a possible destruction of the washing liquid, as it is possible to obtain a phase with a high water content and a phase with a high organic content.

Experiments have shown that the mixture has very good properties for cleaning parts, surfaces and other things from paint, coke, varnish, glue, rubber, plastic, soot and The parts can be cleaned either by dipping in a tank or by applying the solution to the desired surface by brushing or spraying. The cleaning properties are poor in a separated liquid but very good in a homogeneous liquid. It has also been shown that powder coatings, which dissolve in many other washing liquids, are stripped in leather and in this way it is easier to separate the powder coating from the washing liquid to minimize the degradation of the paint.

Stable washing liquid An essential property is that the liquid is stable, i.e. that the components are thermally and chemically stable and that it is not affected in connection with the washing process. In order to achieve an economically advantageous and rational washing process, a stable washing liquid with consistent function over a long period of time is required. Furthermore, the working environment and external environment are of great importance, which limits the choice of components in the liquid.

Functional surfactants In view of achieving a stable washing liquid, the surfactant in particular is of central importance for the function of the washing liquid. The property requirements placed on the surfactants are as follows: 1. Create a stable microemulsion 2. Thermally and chemically stable for a longer period of time. 3. Improve the washing effect of the liquid. 4. Approved according to new and stricter legislation (the detergent directives).

The property requirement to create a stable microemulsion with desired components such as water, benzyl alcohol and an organic carboxylic acid has proven to be difficult to meet for nonionic surfactants such as fatty alcohol ethoxylates, of the type; alkyl glucosides and alcohol ethoxylates and anionic surfactants of the type metal salts of fatty acids, sulfosuccinates and fatty acid sulfonates.

Property requirement 2 has further minimized the number of surfactants where it has been shown that surfactants of the alkyl sulfate, amine oxide and phosphate ester types hydrolyze in the acidic environment and are thus not stable for a longer period of time.

Property requirements 3 and 4 have further reduced the number of relevant surfactants as most cationic quaternary ammonium compounds are not approved according to the detergents directive.

Possible surfactants that meet the four property requirements are anionic or zwitterionic of the type: alkylbenzene sulfonate, alkyl sulfonate, alkylamine diproprionate. Sodium C13-17 alkane sulfonate is particularly preferred.

Activator (co-solvent) The activator used in the washing liquid needs to be an acid. It has been shown that many mineral acids give a pH that is too low and contribute to the breakdown of paint and varnish in the washing liquid, which results in the washing liquid breaking down and losing its effect quickly. In order to be able to make the washing liquid maintain its function for a long time, the activator should be a weaker organic acid that does not break down the paint. If the shortest carboxylic acids are used, such as formic acid, acetic acid and oxalic acid, it also results in the breakdown of paint and varnish and that they are aggressive towards underlying materials. Carboxylic acids, which are more suitable for the system, can be e.g. longer carboxylic acids such as hexanoic acid and heptanoic acid, divalent aliphatic carboxylic acids such as malonic acid and succinic acid, dihydroxy dicarboxylic acids such as tartaric acid, aromatic carboxylic acids such as benzoic acid, d-hydroxy acids such as glycolic acid and lactic acid.

Optimization Optimization of the system by changing the concentrations of the components is of enormous importance for its final washing function. The amount of water and solvent can be varied depending on the requirements of the product such as efficiency, cost, amount of VOC, etc. For a given water-solvent ratio, it has been shown that the best washing effect is reached near the turning point to micro-emulsion. This means that the sum of surfactant and co-solvent should be minimized in relation to the amount of water-solvent. We have therefore found that surfactant and activator must have dual properties to achieve the best washing effect and provide stability to the system. 0 The surfactant should be effective in forming a micro-emulsion and have a proven increased washing effect. 0 The acid should function partly as an activator (and pH adjuster) and partly as a co-solvent. 10 l5 20 535 484 12 A certain amount of acid activates the washing liquid, but a further increased amount of acid does not always give a more effective washing liquid. It can also result in the activator starting to break down washing residues from, for example, the paint, which in turn can lead to the washing liquid losing its effectiveness. As a co-solvent, the acid should help form a microemulsion so that the amount of surfactant can be minimized. If the amount of surfactant in the washing liquid is too high, the washing efficiency will decrease because of this.

The effect of the components is seen from the following test at 80°C: Benzyl- Surfactant Acid Water Mix- ED- Polyester Epoxy- alcohol (%) (äs) (%) powder varnish (powder- polyester (fis) 120um varnish) (mix powder) (time units) 1 O O l O >l 6 > 1 3 2 , 5 91.5 5.5 3 3 >16 4 2.5 96 3.4 3 >16 l 1 88 5.5 3.4 3 >l,5 >3.5 6 2.5 24 8 , 5 3 , 4 64 l l l l By adding an acid (activator) and/or a surfactant, the washing time can be reduced significantly compared to the pure solvent. Adding water to the solvent reduces the washing time further.

If the amount of activator is increased, the time to remove paint can be reduced somewhat, but at the same time it has been shown that the paint dissolves much faster with a higher content of activator. This leads to the washing liquid breaking down and losing its effect faster, which does not lead to a stable and robust washing liquid. 535 484 13 The effectiveness of the washing liquid with different types of acids shows that a low pH does not always give the most effective washing liquid. The different acids can also be effective on different paint systems. 5 Water Benzyl- Surfactant Acid Amount pH Car- Powder- (%) alcohol (%) acid plate mix (%) (100um) (time (time unit) unit) 77 13 9 Oxalic acid 0, 1 1, 93 >6 >3 77 13 9 Benzoic acid 1 2,8 3 2,5 77 13 9 Heptanoic acid 1 3, 63 5 2 77 13 9 Hexanoic acid 1 3,12 5 2,5 77 13 9 Succinic acid l 2,6 2 2,5 77 13 9 Malonic acid O, 5 2, O 3 2 76 13 7 Lactic acid 3,5 2,08 >6 l 77 13 9 Malonic acid 0,38 1,88 >6 >1,5 Lactic acid O, 75 Further comparative tests between two different d-hydroxy acids and a dihydroxy dicarboxylic acid show that the shortest of these acids, glycolic acid, has the greatest washing effect on the washing liquid.

Water Benzyl- Surfactant Acid Amount pH Powder mix (ice) alcohol (ice) acid (140um) (fi) (%) (time unit) 47 34 13.5 Tartaric acid 5.3 2.51 >3 47.5 34 14.5 Lactic acid 3.4 2.87 >2.5 47.5 34 14.5 Glycolic acid 3.4 2.87 1 In a comparative test between glycolic acid and lactic acid, both d-hydroxy acids, it has been shown that 15 glycolic acid is most effective for different compositions of 10 535 484 14 washing liquids when tested on aluminum rims with powder paint, topcoat and clearcoat.

Benzyl- Water Surfactant Acid Amount Temp Al-rim alcohol (%) (%) acid (°C) (80°C) (8) (i) (time unit) 14 78 4.7 Lactic acid 3.3 80 17 25 64 6 Glycolic acid 3.5 80 15 30 60.5 6.5 Glycolic acid 3.5 80 10 30 60.5 6.5 Lactic acid 3.5 so >12 35 53 8 Glycolic acid 3.5 80 12 47 41.5 8 Glycolic acid 3.5 80 14 An increased amount of solvent does not always give more effective washing liquids, but there is a minimum in washing time depending on the amount of solvent. This can be seen for both d-hydroxy acids and the optimum is at a solvent content of 25-30% for glycolic acid and 30-35% for lactic acid.

Stripping of aluminum rims at 80C 18 17 16 15 14 13 12 11 10 Time unit - -l - Glycolic acid å -o- Volic acid 0 20 40 60 80 100 e % solvent 15 20 25 30 535 484 15 It has also been shown that glycolic acid has a certain co-solvent effect which means that the amount of surfactant can be reduced when the amount of acid increases.

Benzyl alcohol Water Acid Surfactant (%) (%) (%) (%) 22.4 71 O 6.45 22.4 70.4 0.93 6.25 22.4 69.8 1.9 5.9 22.4 68.9 3.2 5.5 Inhibitors A problem that can arise when washing painted parts is that the washing liquid can affect the underlying material through pickling, hydrogen evolution, discoloration, etc. This is seen on steel, zinc phosphated, galvanized, cast iron, aluminum alloys, etc. In order to avoid discoloration and possible hydrogen evolution, the washing liquid should contain inhibitors. The desired characteristics of the inhibitors are as follows: 0 environmentally friendly 0 do not affect the microemulsion 0 stable 0 analyzable It has been shown that possible inhibitors consist of benzotriazole, cinnamaldehyde, potassium iodide, hexamethylenetetramine, cinnamonitrile, cinnamic acid, metal salt of alkylamine monoproprionate, metal salt of alkylamine diproprionate, methylamine, sulfadiazine, benzonitrile, chlorobenzonitrile, sodium- sodium nitrite, ethanolamines, 10 15 20 25 30 535 484 16 phosphate, hydroxyethane diphosphonic acid, calcium bicarbonate, metal salt of polyphosphates, phosphonates, hexamethylene tetramine and bismuth trichloride. They have been tested on various metals and have been shown to reduce hydrogen formation significantly and to reduce discoloration on surfaces. All of these inhibitors can be added to the microemulsion without it turning into a two-phase system, i.e. they do not negatively affect the washing function or stability of the washing liquid. They are added in concentrations between 0.05% to 2% of the total mixture. Complex formation Often parts that include metals/salts are washed with the risk that these will leach out and enter the washing liquid. This can in many cases affect the microemulsion and thus also the function of the washing liquid. With the aforementioned mixture, it has proven possible to add complexing agents such as EDTA, NTA, sodium iminodisuccinate, glutamic acid N,N-diacetic acid, phosphonates and polyphosphonates without this in turn affecting the microemulsion of the washing liquid.

The ability of the washing liquid to render dissolved metals/salts harmless increases significantly, and thus the lifespan of the washing liquid.

Analysis The composition of the washing liquid means that most of the water evaporates during continuous use.

In order to maintain the function and stability of the micro-emulsion, the amount of water must be kept at the right level. If the water content in the washing liquid decreases, the effectiveness of the washing liquid can be reduced and any paint and varnish residues can begin to dissolve more easily, which ultimately results in the effectiveness and life of the washing liquid being reduced. However, in a mixture that has lost a lot of water, the water content can easily be restored by adding new ordinary tap water up to the original level without the risk of phase separation.

In order to keep the water content at a constant level, this should be able to be analyzed in a simple and quick analysis in order to be able to check the water level as often as desired. If the liquid is allowed to stand and cool, a certain phase separation will occur so that a two-phase system arises with an upper water-rich and a lower solvent-rich phase. These two phases do not show the true water content as the surfactant still helps to dissolve a certain part of the water in the solvent-rich phase and vice versa. The surfactant is a neutralized sulfonic acid which at a low pH no longer has its surface-active property as it has changed back to the pure acid.

This causes the surfactant's surface-active properties to disappear and it cannot then help dissolve water in the solvent-rich phase and vice versa.

To a 100 ml sample of the washing liquid, 20 ml of hydrochloric acid is added while stirring. The concentration of the acid can be varied depending on the quality of the washing liquid.

The sample is poured into a 100 ml measuring glass and allowed to stand and separate until two phases have formed. The lower phase contains water, water-soluble components from the washing liquid and the added acid. The upper phase contains solvent and water-insoluble components.

To obtain the volume of the water phase in the washing liquid, the volume of the added acid is subtracted from the total volume of the lower phase in the measuring glass. If the water content in the washing liquid is incorrect, it can be adjusted by adding the amount of water up to the original content without risk of phase separation. 10 15 20 25 30 535 484 18 Method and process The mixture can be used for cleaning by dipping, spraying or applying a thickened composition. The composition and concentration of the components can be controlled for the desired application method and temperature.

During dipping, the microstructure and phase system can be controlled to achieve desirable environmental and economic effects, for example in the following ways.

The product can be delivered as a concentrate and diluted at the time of use to a ready-to-use solution.

A used bath can be fractionated/phase separated prior to destruction to achieve environmental and cost benefits by dividing it into, for example; 0 Water 0 Low energy waste 0 High energy waste Rinse water can be separated by pH and salinity adjustments to remove salt water and other residue. Other residue can itself consist of low energy waste or high energy waste.

A cleaning system can reuse the rinse water through continuous phase separation where the alcohol phase is returned to the cleaning bath in the form of a back-flow model.

The invention is of course not limited to the above. Modifications are possible without departing from the scope of the invention as defined in the claims.

Tests conducted were performed on varnishes, but corresponding results also apply to other specified agents 535 484 19 that are desired to be removed, such as rubber, soot, etc. It also applies that formulations for other water contents than those tested can of course also be selected if necessary, depending on the agent that is desired to be removed, and under different conditions that apply.

Claims (12)

10 15 20 25 30 535 484 20 PATENT REQUIREMENTS 1. l. Agents for removing paint, varnish, glue, rubber, plastic, soot and coke or the like on articles containing the agent; a) aromatic alcohol of the benzyl alcohol type with the property of being partially soluble in water, b) water, c) surfactant, and d) acid, characterized in that the agent is a stable microemulsion with a water content of between 60-85% or 4- 20% of the total amount, which is effective in the formation of the surfactant, of a microemulsion and whose content amounts to a maximum of 8% calculated on the total amount, consists of anionic or zwitterionic type; alkylbenzene sulfonate, alkylsulfonate or alkylamine diproprionate, the benzyl alcohol content is between 8-30% or 70-94% of the total amount and that the acid used as activator (co-solvent) of the detergent is a weaker organic acid such as carboxylic acids hexanoic acid and heptanoic acid, divalent aliphatic carboxylic acids such as malonic acid and succinic acid, dihydroxy dicarboxylic acid such as tartaric acid, aromatic carboxylic acids such as benzoic acid, d-hydroxy acids such as glycolic acid and / or lactic acid or a mixture thereof. Composition according to Claim 1, characterized in that the mixture formed contains an anti-corrosion inhibitor in the form of benzotriasol, cinnamon aldehyde, potassium iodide, hexamethylene tetramine, cinnamonitrile, cinnamic acid, metal salt of alkylamine monopropionate, metal salt of 48 , methylamine, sulfadiazine, benzonitrile, chlorobenzonitrile, sodium nitrite, ethanolamines, sodium phosphate, hydroxyethane diphosphoric acid, calcium bicarbonate, metal salt of polyphosphates, phosphonates, hexamethylene tetramine and bismuth trichloride. Agent according to Claim 1, characterized in that the mixture formed contains an anti-corrosion inhibitor, such as benzotriasol, potassium iodide, hexamethylenetetramine, cinnamaldehyde, cinnamonitrile, metal salt of alkylamine diproprionate, benzonitrile and bismuth trichloride. Composition according to any one of the preceding claims, characterized in that the mixture formed contains a complexing agent such as EDTA, NTA, sodium iminodisuccinate, glutaric acid, N, N-diethic acid, phosphonates and polyphosphonates or a mixture thereof. Agent according to one of the preceding claims, characterized in that the mixture formed also contains cellulose-type thickeners for increasing the viscosity. Agent according to one of the preceding claims, characterized in that the surfactant is paraffin sulfonate. Composition according to any one of the preceding claims, characterized in that the surfactant is sodium C13-17 alkanesulfonate. 10 15 20 25 30 535 484 22 Agent according to any one of the preceding claims, characterized in that the mixture consists of; a) aromatic alcohol 8-30% of the total amount, b) water 60-85% of the total amount, c) surfactant 0.5-8% of the total amount and d) acid 0.5-8% of the total amount. Composition according to any one of the preceding claims 1-7, characterized in that the mixture consists of; a) aromatic alcohol 70-94% of the total amount, b) water 4-20% of the total amount, c) surfactant 0.5-6% of the total amount and d) acid 0.5-6% of the total amount. Composition according to any one of the preceding claims, characterized in that the mixture additionally contains co-solvents of between 0.5-10% of the total amount for the purpose of altering the physical and chemical properties. 11. ll. Use of agents according to any one of the preceding claims, characterized in that the agent is used for removing e.g. paint, varnish, glue, rubber, plastic, soot or coke from fixtures or objects that you wish to clean from the same before re-use or for e.g. revision. Use according to claim 11, characterized in that the agent is used at an elevated temperature in the range 40-90 ° C.