EP2556121A1

EP2556121A1 - Means for removal of for example paint and the use of the same

Info

Publication number: EP2556121A1
Application number: EP11766251A
Authority: EP
Inventors: Patrik Gondel; Cecilia Groth
Original assignee: Envirochem IEC AB
Current assignee: Envirochem IEC AB
Priority date: 2010-04-08
Filing date: 2011-04-07
Publication date: 2013-02-13
Also published as: SE535484C2; WO2011126452A1; SE1050346A1; EP2556121A4

Abstract

The present invention relates to an agent for the removal of paint, varnish, glue, rubber, plastic, soot and coke or the like on objects. The agent contains: a) aromatic alcohol having the property of being partially soluble in water, b) water c) tenside, and d) acid. According to the invention, the tenside consists of anionic, alternatively zwitterionic ones of the type alkylbenzene sulphonate, alkylsulphonate or alkylamine diproprionate. The acid that is used as an activator (co- solvent) of the liquid cleaning agent in question is a weaker organic acid such as carboxylic acids such as hexane acid and heptane acid, divalent aliphatic carboxylic acids such as malonic acid and succinic acid, dihydroxydicarboxylic acid such as tartaric acid, aromatic carboxylic acids such as benzoic acid, a-hydroxy acids such as glycolic acid and/or lactic acid, or a mixture thereof. The invention also relates to a use of the agent for the removal of paint, etc., from objects.

Description

S87 P4PCT LG/KOE

Means for removal of, for example paint and the use of the same . The present invention relates to an agent for the removal of paint, varnish, glue, rubber, plastic, soot, coke or the like from objects, the agent containing: a) aromatic alcohol of the type benzyl

alcohol having the property of being partially soluble in water, b) water,

c) tenside, and

d) acid.

Background

There are many alternative commercial solutions for the removal of paint, varnish, glue, rubber, plastic, soot and coke. In many cases, chlorinated

solvents are still used as a commercial alternative in spite of their unwanted environmental properties.

For many years, strong bases or acids have, however, been the alternative. But their detergent power is poor at the same time as they are downright dangerous to handle from a working environment point of view. Another pair of negative aspects is that several materials and surface dressings are attacked by strong bases and acids, respectively, and that the waste is expensive to destruct after consumption.

The development has successively turned into solvents of the type alcohol compounds, NMP, DBE, and the like. The effect is strongly varying, and most often alkaline salts of the type hydroxides, alternatively strong acid compounds, are used as accelerators to achieve an acceptable effect. Again, this implies several

disadvantages since several materials do not resist said solutions, the working environment becomes bad, and the service life of the product upon repeated use will be limited.

Examples of some known solutions of the type mentioned are shown, e.g., in US 2007/0087952 Al, CA 2,275,304 Al and CA 2,378,886 Al .

Desirable properties of a liquid detergent within the mentioned area are the following:

• Water-based (common tap water)

• Low organic contents

• Low VOC

• Surface-active substances with low environmental

impact

• Kind to subjacent materials and surface dressings

• Thermally and chemically stable

• Environmentally proper/environmental-friendly

components

Additional desires of a mixture are that residues of paint and varnish should not be decomposed in the liquid since these decomposition products impair the detergent effect of the liquid until it is unusable. In earlier systems on the alkaline side, it has turned out that powder coatings are washed away in a fine powder that is rapidly decomposed and makes the liquid detergent unusable. In order to minimize this degradation, it is therefore desirable that, among other things, powder coatings are washed away as a skin so as to minimize dissolution of paint residues into the system.

Therefore, the main object of the present invention is primarily to solve, among other things, the problems mentioned above and also allow the simple and functional use of the agent.

Said object is achieved by means of an agent according to the present invention that essentially is characterized in that the tenside consists of anionic, alternatively zwitterionic ones of the type alkylbenzene sulphonate, alkyl sulphonate or alkylamine diproprionate, and that the acid that is used as an activator (co- solvent) of the liquid cleaning agent in question is a weaker organic acid such as carboxylic acids such as hexane acid and heptane acid, divalent aliphatic

carboxylic acids such as malonic acid and succinic acid, dihydroxydicarboxylic acid such as tartaric acid, aromatic carboxylic acids such as benzoic acid, a-hydroxy acids such as glycolic acid and/or lactic acid, or a mixture thereof .

Use of said agent for the removal of paint, etc., from objects according to the present invention is essentially characterized in that the agent is used for the removal of, e.g., paint, varnish, glue, rubber, plastic, soot or coke from fixtures or objects desired to be cleaned by dipping, spraying or application of a thickened composition of the same before renewed use or for, e.g., reprocessing.

Comparison with further prior art

According to the invention, tensides are utilized to make the aqueous phase and the solvent phase to coexist in a so-called microemulsion . A microemulsion is a homogeneous phase where small domains of a solvent exist together with other small domains of another solvent without the solvents being mixed with each other. In the present case, the phases are water and benzyl alcohol. This makes that the solvent is not diluted by water but it keeps its properties as a solvent. The structure in the microemulsion with water/solvent domains contributes to increase the function of the liquid compared with a diluted system.

The tensides that are mentioned in the patent application have on one hand met the requirement of forming a microemulsion between water and solvent, but they are also chemically stable in an acid environment at an elevated temperature for a longer time. After having tested some 50 tensides in these conditions, it has turned out that only three groups have managed to both form a microemulsion and be stable at a low pH at an elevated temperature. The tensides that have turned out to be usable are alkylbenzene sulphonate, alkyl sulphonate or alkylamine diproprionate .

US 5,454,985 A, US 7,052,556 Bl and US 2005/026799 Al concern agents that clearly differ from the new defined agent.

In US 5,454,985 A, sodium xylene

sulphonate is used, which is a hydrotrope and no tenside. The difference between a tenside and a hydrotrope is that a tenside is a strongly surface-active molecule and a hydrotrope is a very weakly surface-active molecule. This difference makes that a tenside self-aggregates while a hydrotrope only is accumulated at interfaces, which results in a hydrotrope not being able to form aggregates in the same way as a tenside can. Accordingly, it cannot by itself form a microemulsion of solvent and water as a tenside can. Hydrotropes are used, on one hand, to

dissolve hydrofob (non-water-soluble) substances into water, or to disrupt the order of tensides that have self- aggregated.

In US 7,052,556 Bl, they are using sodium lauryl sulphate that is a tenside that also has been tested, and it manages to form a microemulsion but it is not stable at a lower pH and elevated temperature, when it is being decomposed.

In US 2005/026799 Al, they mention

tenside, but they are at a pH > 7 as well as make use of hydrogen peroxide as an activator. The hydrogen peroxide is consumed, which makes that the liquid detergent cannot be used continuously but has to be replaced.

Alternatively, extra additions of hydrogen peroxide have to be made continuously. Controllable microstrueture and phase division

The present invention solves several problems in a very structural way. The invention consists of a solution consisting of primarily, however not limited to, water, benzyl alcohol, tenside and activator (co- solvent) .

The components should have such a

composition that they, in the desired cleaning condition, will form a single-phase system such as a microemulsion. The formation of microemulsion is controlled by

temperature, concentration of included components, pH and/or salt adjustments. This provides a two-phase system with a water-rich phase and a solvent-rich phase at low temperatures that, at a temperature increase, undergoes a phase transformation into a single-phase system

(microemulsion) . The phase transformation temperature can be controlled by the concentration of the included components being altered. The advantages of this are that an efficient process can be provided with economical as well as environmental advantages in the form of, among other things, the following:

• The product can be delivered in a single-phase

concentrate and be diluted with tap water on-site.

• The concentration of included components can be

minimized/optimized in respect of the desired cleaning temperature.

• A simple analysis method to determine the contents

(the content of water/solvent) in the bath generates an efficient and simple conditioning of the bath upon continuous use.

• A system for the purification and management of

rinsing water can be provided.

• A system for the return of desired components from the rinsing water to the cleaning liquid can be provided .

• A system that separates waste and used/consumed

liquid into different fractions depending on energy content, water content and impurities can be

provided.

Stable and efficient basic mixture

The main object of the present invention is to provide an efficient and stable mixture for said cleaning purposes combined with environmental and

economical advantages.

It is known that some solvents achieve a better cleaning power together with water, in the form of a stable microemulsion . Such a solvent has to be non- miscible or only partially miscible with water. A type of solvent that has turned out to have very good cleaning properties is aromatic alcohols, such as, e.g., benzyl alcohol

It has turned out that an increased amount of water in the single-phase system renders more effective the detergent effect for many paints, varnishes, plastics, etc. Benzyl alcohol together with a limited amount of water as well as the other mentioned components have also a certain detergent effect on some systems. However, it has turned out that a microemulsion with high water content gives an increased detergent effect on most materials, such as paint, varnish, glue, rubber, plastic, soot and coke. The high water concentration also reduces the ability of dissolution into the mixture of possible decomposition products from paint, varnish, glue, rubber, plastic, soot or coke, which contributes to an extended useful life of the liquid detergent. Furthermore, a high water concentration entails improved environmental

properties as well as better economical conditions for the liquid detergent.

Requirements of an efficient microemulsion:

• Good penetration of the liquid detergent through the material

• The microemulsion should be stable in spite of

dissolution of other components.

• The liquid detergent should not disintegrate residues of paint, varnish, glue, etc., but they should be kept integrated in skins in order to minimize the degradation of the liquid detergent.

Microemulsions are highly sensitive and phase-separate easily upon load in the form of, e.g., cleaning. On the contrary, said mixture has turned out to be very stable in spite of a certain intermixture of, e.g., paint residues. Depending on the concentration of the different components in the composition, also

different desirable properties can be achieved besides good cleaning power. The composition of the included components can be varied from a homogeneous mixture at room temperature, which provides products that can be used without heating (resulting in a lower detergent effect) , to mixtures that are not homogeneous at room temperature but at a higher temperature with a better and faster detergent effect as a result. In such a way, a mixture can be tailor-made so that it suits the specific application in the best way.

The phases of the mixture are stable in spite of temperature fluctuations above the temperature at which the microemulsion is formed. It is also possible to get a cooled mixture to become homogeneous again upon heating, this is independent of how many times that it occurs provided the mutual relationship between the components in the mixture is stable.

This phase separation may also be utilized in a possible destruction of the liquid detergent by it being possible to derive a phase having high water content and a phase having high organic contents.

Experiments have shown that said mixture has very good properties for the cleaning of details, surfaces and other things from paint, varnish, glue, rubber, plastic, soot and coke. The details can be cleaned either by dipping in a tank or by applying the solution on a desired surface by brushing or spraying. The cleaning properties are poor in a separated liquid but very good for a homogeneous liquid. It has also turned out that powder coatings, which disintegrate in many other liquid detergents, are depainted into skin, and in such a way, it is easier to be able to separate off the powder coating from the liquid detergent in order to minimize the decomposition of the paint. Stable liquid detergent

An essential property is that the liquid is stable, i.e., that the included components are

thermally and chemically stable as well as that it is not affected in connection with the cleaning process. In order to achieve an economically advantageous and efficient cleaning process, a stable liquid detergent having a long- term constant function is required. Furthermore, the working and external environments are important, which limit the selection of components included in the liquid.

Working tensides

In the light of obtaining a stable liquid detergent, particularly the tenside is of central

importance to the function of the liquid detergent. The requirements that are made on the tensides are the following :

1. Create a stable microemulsion .

2. Long-term thermally and chemically stable.

3. Improve the detergent effect of the liquid.

4. Approved according to new and stronger

legislation (the detergent directives).

Requirement 1 of creating a stable

microemulsion with desired components such as water, benzyl alcohol as well as an organic carboxylic acid has turned out to be difficult to fulfil for nonionic

tensides, e.g., of the type fatty alcohol ethoxylate, alkyl glucosides and alcohol ethoxylate, and anionic ones of the type metal salts of fatty acids, sulphosuccinate and fatty acid sulphonate.

Requirement 2 has further minimized the number of tensides, wherein it has turned out that tensides of the type alkyl sulphate, aminoxide and phosphate esters hydrolyse in the acid environment and thereby are not long-term stable.

Requirements 3 and 4 have further reduced the number of appropriate tensides, since most cationic ones of the type quaternary ammonium compounds are not approved according to the detergent directive.

Possible tensides that meet the four requirements are anionic, alternatively zwitterionic ones of the type alkylbenzene sulphonate, alkyl sulphonate, alkylamine diproprionate . Particularly, sodium C13-17 alkane sulphonate is preferred.

Activator (co-solvent)

The activator that is used in the liquid detergent needs to be an acid. It has turned out that many mineral acids provide too low a pH and contribute to decomposition of paints and varnishes in the liquid detergent, which results in the liquid detergent being degraded and losing effect rapidly. In order to be able to get the liquid detergent to keep its function for a long time, the activator should be a weaker organic acid that does not decompose the paint. Should the shortest

carboxylic acids, such as formic acid, acetic acid and oxalic acid be used, this also results in paints and varnishes being decomposed, as well as that they are aggressive to subjacent materials. Carboxylic acids that are more suitable for the system may be, e.g., longer carboxylic acids such as hexane acid and heptane acid, divalent aliphatic carboxylic acids such as malonic acid and succinic acid, dihydroxydicarboxylic acid such as tartaric acid, aromatic carboxylic acids such as benzoic acid, a-hydroxy acids such as glycolic acid and lactic acid .

Optimization

Optimization of the system by changing the contents of the included components is tremendously important for its final detergent power. 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 ratio of water/solvent, it has turned out that the best detergent effect is achieved close to the point of transition to microemulsion. This means that the sum of tenside and co-solvent should be minimized in relation to the amount of water/solvent.

Therefore, we have found that tenside and activator have to have double properties to achieve the best detergent effect as well as afford stability to the system.

• The tenside should be efficient in the formation of a microemulsion and have a proved increased detergent effect .

• The acid should work both as an activator (and pH

adjuster) and as a co-solvent.

A certain amount of acid activates the liquid detergent, but a further increased amount of acid does not always have to give a more efficient liquid detergent. This may also result in the activator

beginning to decompose cleaning residues emanating from, e.g., the paint, which in turn may cause the liquid detergent to lose efficiency. As a co-solvent, the acid should assist in forming a microemulsion so that the amount of tenside can be minimized. Should the amount of tenside become too great in the liquid detergent, this will cause the detergent efficiency to decrease.

Examples of highly efficient agents and the content of alcohol, water, tenside and acid included therein are according to the following:

The agent contains:

a) benzyl alcohol at a content lower than 30 % or higher than 80 %,

b) water at a content lower than 19 % or higher than 65 %, c) tenside at a content lower than 15 %, and

d) acid at a content of between 1 and 5 %.

For all examples and for the invention, it applies that pH < 7.

The effect of the included components is seen from the following test at 80 °C:

By adding an acid (activator) and/or a tenside, the cleaning time can be substantially decreas compared with that for the pure solvent. An addition of water to the solvent decreases the cleaning time furthe

If the amount of activator is increased the time to remove paint can be decreased somewhat, but simultaneously it has turned out that the paint is disintegrated considerably faster with a higher content of activator. This results in the liquid detergent being degraded and losing effect faster, which does not give rise to a stable and robust liquid detergent.

The efficiency of the liquid detergent with different types of acids shows that a low pH does not always provide the most efficient liquid detergent. The various acids may also be efficient for different paint systems .

Additional comparative tests between two different a-hydroxy acids as well as a

dihydroxydicarboxylic acid show that the shortest one of these acids, glycolic acid, has the greatest detergent effect on the liquid detergent.

Water Benzyl tenside Acid Amount PH Powder (%) alcohol (%) of mix

(%) acid (140 urn)

(%) (time unit)

47 34 13, 5 Tartaric 5,3 2, 51 >3 acid

47,5 34 14, 5 Lactic 3,4 2,87 >2, 5 acid

47,5 34 14,5 Glycolic 3,4 2, 87 1 acid

In a comparative test between glycolic acid and lactic acid, both a-hydroxy acids, it has turned out that glycolic acid is most efficient for different compositions of liquid detergents in a test on aluminium rims having powder paint, finishing coat and clear coat.

Benzyl Water tenside Acid Amount Temp Al rim alcohol

(%) (%) of (°C) (80 °C) (%)

acid (time (%) unit)

14 78 4,7 Lactic 3, 3 80 17 acid

25 64 6 Glycolic 3, 5 80 10 acid

25 64 6 Lactic 3,5 80 15 acid

30 60, 5 6, 5 Glycolic 3,5 80 10 acid

30 60, 5 6, 5 Lactic 3,5 80 >12 acid

35 53 8 Glycolic 3,5 80 11 acid

35 53 8 Lactic 3, 5 80 12 acid

47 41.5 8 Glycolic 3,5 80 14 acid An increased amount of solvent does not always provide more efficient liquid detergents, but there is a minimum in cleaning time depending on the amount of solvent. This can be observed for both a-hydroxy acids, and this optimum is at a solvent content of 25-30 % for the glycolic acid and 30-35 % for the lactic acid.

Paint stripping of an aluminum alloy wheel at 80°C

9

8

0 20 40 60 80 100

% solvent

It has also turned out that the glycolic acid has a certain co-solvent effect, which allows the amount of tenside to be decreased when the amount of acid increases .

Benzyl alcohol Water (%) Acid (%) tenside (%) (%)

22, 4 71 0 6,45

22, 4 70,4 0, 93 6,25

22, 4 69, 8 1,9 5, 95

22, 4 68, 9 3,2 5,5 Inhibitors

A problem that can arise in the cleaning of lacquered details is that the liquid detergent may affect subjacent materials by pickling, hydrogen gas generation, discoloration, etc. This is observed on steel, zinc phosphated, galvanized, cast iron, aluminium alloys, etc. In order to be able to avoid discoloration and possible hydrogen gas generation, the liquid detergent should contain inhibitors. The desires on the inhibitors are the following:

• environmentally proper

• do not affect the microemulsion

• stable

• analysable

It has turned out that possible inhibitors consist of benzotriazole, potassium iodide, hexamethylene tetramine, cinnamic aldehyde, cinnamonitrile, cinnamic acid, metallic salt of alkylamine monoproprionate, metallic salt of alkylamine diproprionate, methylamine, sulphadiazine, benzonitrile, chlorobenzonitrile , sodium nitrite, ethanol amines, sodium phosphate, hydroxyethane diphosphoric acid, calcium bicarbonate, metallic salt of polyphosphates, phosphonates , hexamethylene tetramine as well as bismuth trichloride. They have been tested on different metals and it has turned out that they reduce the formation of hydrogen gas substantially as well as that they decrease discoloration of the surfaces. It is possible to add all these inhibitors to the microemulsion without the same transforming into a two-phase system, i.e., they do not affect the detergent power or stability of the liquid detergent negatively. They are added in contents of between 0,05 % to 2 % of the total mixture

Complex formation

Often, details are cleaned that include metals/salts with the risk of the same being washed out and entering into the liquid detergent. This may in many cases affect the microemulsion and thereby also the function of the liquid detergent.

With said mixture, it has turned out to be possible to add chelating agents of the type EDTA, NTA, sodium

iminodisuccinate , glutaric acid-N, N-diacetic acid, phosphonates and polyphosphonates without this in turn affecting the microemulsion of the liquid detergent. The possibility for the liquid detergent to neutralize

dissolved metals/salts increases considerably and thereby the useful life of the liquid detergent.

Analysis

The composition of the liquid detergent makes that water mostly evaporates upon continuous use. In order to be able to maintain the function and stability of the microemulsion, the amount of water has to be held on a correct level. If the water content decreases in the liquid detergent, the efficiency of the liquid detergent may be decreased as well as that possible paint residues and varnish residues begin to disintegrate easier, which in the end results in the efficiency and the useful life of the liquid detergent decreasing. However, in a mixture that has lost much water, the water content can easily be restored by adding new common tap water up to the original content without risking phase separation. In order to be able to keep the water content on a constant level, this should be analysable in a simple and quick analysis in order to, in such a way, be able to check the water level as often as desirable. If the liquid is allowed to rest and cool down, a certain phase separation will occur so that a two-phase system arises having an upper water-rich and a lower solvent-rich phase. These two phases do not exhibit the correct water content, since the tenside still assists in dissolving a certain part of water into the solvent-rich phase and vice versa. The tenside is a neutralized sulphonic acid that, at a low pH, no longer holds its surface-active property when it has transformed into the pure acid again. This gives rise to the surface-active property of the tenside disappearing, and then it cannot assist in dissolving water into the solvent-rich phase and vice versa.

To a 100 ml sample of the liquid detergent, 20 ml of hydrochloric acid is added during stirring. The concentration of the acid can be varied depending on the quality of the liquid detergent. The sample is poured into a 100 ml graduated glass, and it is allowed to rest and separate until two phases have been formed. The lower phase contains water, water-soluble components from the liquid detergent as well as the added acid. In the upper phase, there are solvent and non-water-soluble components. In order to derive the volume of the aqueous phase in the liquid detergent, the volume of the added acid is

subtracted from the total volume of the lower phase in the graduated glass. Should the water content in the liquid detergent be incorrect, this can be adjusted by adding the amount of water up to the original content without risking phase separation. Method and process

Said mixture can be used for cleaning by dipping, spraying or application of a thickened

composition. The composition and concentration of the included components can be controlled for the desired application method and application temperature.

In dipping, the microstructure and the phase system can be controlled to achieve desirable effects on the environment and the economy in, e.g., the following way.

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

Before a destruction, a used bath may be fractionated/phase-separated in order to attain

environmental and cost benefits by division into, for example :

• Water

· Low-energy waste

• High-energy waste

Rinsing water may be separated by pH and salinity adjustments to derive salt water and other residues. Other residues may consist of low-energy waste and high-energy waste, respectively.

A cleaning system may reuse the rinsing water by

continuous phase separation where the alcohol phase is returned to the cleaning bath in the form of a back-flow model .

The invention is naturally not limited to the above-mentioned. Modifications are feasible without departing from the protection area of the invention such as it is defined in the claims. Made tests are conducted on varnishes, but the corresponding results apply also to other mentioned matter desired to be removed, such as rubber, soot, etc. It also applies that formulations for other water contents than the ones tested are naturally also allowed to be selected if required, depending on the matter desired to be removed, and on different conditions that exist.

Claims

S87 P4PCT LG/ASL CLAIMS

1. Agent for the removal of paint, varnish, glue, rubber, plastic, soot and coke or the like on objects, the agent containing:

a) aromatic alcohol of the type benzyl alcohol

having the property of being partially soluble in water,

b) water,

c) tenside, and

d) acid,

characterized in that the tenside consists of anionic, alternatively zwitterionic ones of the type alkylbenzene sulphonate, alkyl sulphonate or alkylamine diproprionate, and

that the acid that is used as an activator (co- solvent) of the liquid cleaning agent in question is a weaker organic acid such as carboxylic acids such as hexane acid and heptane acid, divalent aliphatic

carboxylic acids such as malonic acid and succinic acid, dihydroxydicarboxylic acid such as tartaric acid, aromatic carboxylic acids such as benzoic acid, -hydroxy acids such as glycolic acid and/or lactic acid, or a mixture thereof.

2. Agent according to claim 1, characterized in that the content of benzyl alcohol is between 6 and 94 % as counted on the total amount.

3. Agent according to any one of the

preceding claims, characterized in that the formed mixture contains an anti-corrosion inhibitor in the form of benzotriazole , potassium iodide, hexamethylene tetramine, cinnamic aldehyde, cinnamonitrile, cinnamic acid, metallic salt of alkylamine monoproprionate, metallic salt of alkylamine diproprionate, methylamine, sulphadiazine, benzonitrile, chlorobenzonitrile, sodium nitrite, ethanol amines, sodium phosphate, hydroxyethane diphosphoric acid, calcium bicarbonate, metallic salt of polyphosphates, phosphonates, hexamethylene tetramine as well as bismuth trichloride .

4. Agent according to any one of the preceding claims 1-2, characterized in that the formed mixture contains an anti-corrosion inhibitor, such as

benzotriazole, potassium iodide, hexamethylene tetramine, cinnamic aldehyde, cinnamonitrile, metallic salt of alkylamine diproprionate, benzonitrile as well as bismuth trichloride, or a mixture thereof.

5. Agent according to any one of the preceding claims, characterized in that the formed mixture contains a chelating agent, such as EDTA, NTA, sodium

iminodisuccinate , glutaric acid-N, N-diacetic acid, phosphonates and polyphosphonates , or a mixture thereof.

6. Agent according to any one of the preceding claims, characterized in that the formed mixture in addition contains a thickener of the type cellulose for increasing the viscosity.

7. Agent according to any one of the preceding claims, characterized in that the tenside consists of paraffin sulphonate.

8. Agent according to any one of the preceding claims, characterized in that the tenside consists of sodium C13-17 alkane sulphonate.

9. Agent according to any one of the preceding claims, characterized in that the content of water is between 6 and 94 % as counted on the total amount.

10. Agent according to any one of the preceding claims, characterized in that the tenside admixture is between 0,5 and 10 % of the total amount.

11. Agent according to any one of the preceding claims, characterized in that the portion of acid is 0,5-

20 % of the total amount.

12. Agent according to any one of the preceding claims 1-9, characterized in that the mixture consists of: a) aromatic alcohol at 20-50 % of the total amount, b) water at 25-80 % of the total amount,

c) tenside at 0,5-8 % of the total amount, and d) acid at 0,5-8 % of the total amount.

13. Agent according to any one of the preceding claims 1-9, characterized in that the mixture consists of: a) aromatic alcohol at 8-30 % of the total amount, b) water at 60-85 % of the total amount,

14. Agent according to any one of the preceding claims 1-9, characterized in that the mixture consists of: a) aromatic alcohol at 70-94 % of the total amount, b) water at 4-20 % of the total amount,

c) tenside at 0,5-6 % of the total amount, and d) acid at 0,5-6 % of the total amount.

15. Agent according to any one of the preceding claims, characterized in that the mixture in addition contains co-solvents at between 0,5-10 % of the total amount with the purpose of changing the physical and chemical properties.

16. Agent according to claim 1, characterized in that the agent contains :

a) benzyl alcohol at a content lower than 30 % or higher than 80 %,

d) acid at a content of between 1 and 5 %.

17. Agent according to any one of the preceding claims, characterized in that pH < 7.

18. Use of agent for the removal of paint, etc., on objects according to any one of the preceding claims, characterized in that the agent is used for the removal of, e.g., paint, varnish, glue, rubber, plastic, soot or coke from fixtures or objects desired to be cleaned from the same before renewed use or for, e.g., reprocessing.

19. Use according to claim 18, characterized in that the agent is used at an elevated temperature in the range of 40-90 °C.