DE4202320A1 - Impregnating substrate by contact with supercritical fluid contg. impregnant - followed by conversion of fluid to subcritical state - Google Patents

Abstract

In impregnation of substrates, the impregnant is taken up in a super-critical fluid and the substrate is contacted with the fluid. During and/or after the contact, the fluid is converted to the sub-critical state. Impregnation is at 10-300 (32-180) deg.C and 60-400 (140-300) bars. The supercritical fluid is an alkane, esp. ethane, propane or pentane, NH3, a fluorochloroalkane, CO2 and/or CO, opt. contg. 1-10 (2-5) vols.% of a moderator. The impregnants are preservatives, light protectants, plasticisers, hydrophobising or hydrophilising agents, antistatics, anti-parasite agents, bactericides, bacteriostats, perfumes, flavourings, and/or dyes. After the given time of application, the pressure is reduced in stages. USE/ADVANTAGE - The process is environment-friendly, uses no organic solvent, and gives a substrate free from residues of fluid. The fluid and residual impregnant can be collected and re-used. Claimed substrates are natural substrates, ceramics, leather, paper, wood, books, antiquities, cereals, plant seeds, seed corn, foods, luxuries, medicaments or carriers for medicaments, pharmaceuticals or pharmaceutical additives, rubber, synthetics, waxes and soaps. Cigarettes can be impregnated with flavourings or aromas, and cosmetics, lipsticks, fashion trimmings and souvenirs can be impregnated with perfumes or dye

Description

The present invention relates to a method with the Merk paint the preamble of claim 1.

To substrates, such as semi-finished or finished products made of leather, paper, wood or the like, against external influences protect, it is known to impregnate these substrates to provide kidney agents. Imprints can also be made on substrates kidney agents are applied, the corresponding active ingredients included, so as to determine the impregnated substrate to lend. In order to impregnate such The means to apply substrates are usually in dissolved organic solvents and then arrive with the Substrate in contact.  

However, the use of such solvents involves some problems. So when using it a number of Safety regulations to be observed, which in some cases considerable effort is required. Depending on the solvent used can also pose a hazard both the workplace and an environmental hazard the environment occur. In addition, according to the Impregnation of solvent residues on the substrate Adsorption or absorption stick, which in particular is very worrying when it comes to toxic solvents act and the substrates for human or animal consumption are suitable.

The present invention is based on the object Processes for impregnating substrates are available too with the corresponding environmentally friendly Impregnants can be applied to substrates.

This object is achieved by a method with the characterizing features of claim 1 solved.

The method according to the invention for impregnating substrates provides that the impregnating agent is in a fluid takes and then the substrate with the fluid for a certain Time in contact. At least one is used as the fluid supercritical fluid, which one after the elapse of the certain Time transferred to the non-critical state. With others Words is in the method according to the invention in the  State of the art solvents used by an overcri table fluid replaced. Here the supercritical fluid serves that also as a supercritical fluid or supercritical or supercritical gas is referred to as a carrier medium for the impregnation agent to be applied to the substrate. Under over critical fluid are within the scope of the present application such originally gaseous or liquid systems stand by increasing the pressure and increasing accordingly hung the temperature above its critical point for each Fluid is a characteristic quantity. Here then has such a supercritical fluid approximately the viscosity of a gas and a density based on that approximately with the density of the corresponding liquefied Gases is comparable. This leads to an overcri table fluid with excellent dissolving properties a variety of waterproofing agents and due to its gas-like viscosity an excellent penetration ver likes of substrates.

The method according to the invention has a number of advantages on. This is due to the fact that the inventive method dispensed with organic solvents and replaced them instead table fluids are used in the inventive method ren the security requirements required in the prior art fonts reduced to a minimum. Furthermore, it can the method according to the invention does not result in an ad or ab sorption of used to apply the impregnating agent Solvents come because of the process according to the invention  supercritical fluids used by a relatively simple pressure reduction or temperature increase to be carried out or by a corresponding increase in volume in the gaseous state, thereby achieving that possibly ad- or absorbed residues of the substrate Fluids are converted to the gas state and thus that suitably impregnated substrate absolutely free of Fluid residue. Also, in the ver drive the fluid used relatively easily caught and thus used again for impregnation will.

Furthermore, the method according to the invention has the advantage that impregnant residues present in the fluid can be used easily and without problems it is only necessary to change the Pressure, temperature and / or volume. The impregnating agent then falls as a corresponding sub punch while the fluid escapes in gaseous form and correspond can be collected and reused if necessary.

Basically, the method according to the invention is directed the temperature at which the impregnation is carried out according to the fluid used and the temperature resistance of the substrate to be impregnated. Practice The impregnation is carried out at one temperature between about 10 ° C and about 300 ° C, preferably between about 32 ° C and 180 ° C.  

Regarding the pressure, it should be noted that this depends on the Weil selected temperature and the respectively used Fluid depends. Here pressures are used, the between about 60 bar and about 400 bar, preferably between about 140 bar and about 250 bar.

The selection of the one used in the method according to the invention On the one hand, ten fluids depend on the respective application impregnating agent, d. H. the solubility in the respective against fluid, and on the other hand depending on whether the substrate is also in is insoluble in the selected fluid. Under consideration These two criteria can be considered in the case of the invention In principle, any fluid can be used according to the method. For this purpose, alkanes are preferably used as the supercritical fluid, especially ethane, propane or pentane, ammonia, fluorine-chlorine Alkanes, and / or carbon monoxide, either alone or in Mix used with each other. It is particularly suitable yes, if you use carbon dioxide as a supercritical fluid det, because this fluid is toxicologically and ecologically harmless is.

For example, using the method according to the invention a non-polar impregnating agent are applied, so suitable alkanes, preferably ethane, are used in this fluid Temperatures above about 35 ° C and a pressure of about is preferred above 50 bar. The same applies to propane temperatures above about 100 ° C and the pressure  above about 42 bar, while the supercritical fluid pen tan, which is also used to apply non-polar impregnation medium is used, temperatures above about 197 ° C. and pressures above about 34 bar.

The supercritical fluid trifluorochloroethane, which in comparison is more polar to the abovementioned alkanes Impregnations with more polar impregnants, the corresponding temperatures here above 29 ° C and the corresponding pressure is above about 38 bar.

If the supercritical fluid is selected, ethylene will be used Impregnation temperatures above 9 ° C and impregnation pressures preferred above 50 bar, while the polar overcri table fluid ammonia temperatures above 132 ° C and requires a pressure above about 120 bar.

Particularly good results in terms of impregnation one aims in the process according to the invention if one with supercritical carbon dioxide works in this supercritical fluid the temperatures above 32 ° C and the pressures are above 74 bar. Could be surprising found that this supercritical fluid is very good Dissolving properties for a variety of impregnating agents points without causing undesirable changes in properties of the substrate. Furthermore, this is supercritical tables fluid carbon dioxide nontoxic, so that in the event of a leak activity in each case to carry out the invention  In the process, autoclaves used no significant danger occurs. This supercritical fluid is also in the required quantities from natural sources are available, so that when using carbon dioxide no additional order world impairment occurs.

Another embodiment of the method according to the invention provides that the supercritical fluid is a moderator adds in order to achieve that the respective Imprä gnierier is more soluble in the supercritical fluid. By adding the moderator, the polarity of the change critical fluids in any way. For example the polarity of the supercritical fluid is increased, This is how moderators are used, who are already there are polar, such as water or aqueous brine sung. In the same way, by adding moderators the polarity of the fluid can be reduced, e.g. B. by Zu set of alkanes to polar fluids, such as Ammonia.

The concentrations are usually the above ten moderators in the supercritical fluid or fluid mixture between about 1% by volume and about 10% by volume, preferably between about 2% by volume and about 5% by volume, based on the Volume of the fluid or fluid mixture used in each case.

According to the method of the invention, both as sub strat intermediates as well as finished products treated  the. The Ver according to the invention can be particularly successful drive on natural substrates, such as leather in particular, Use paper, wood or porous ceramics as follows is still based on the exemplary embodiments. Also it was found that valuable antiques, such as for example books or wooden antiques, permanently against Environmental influences are protected without it becoming a unwanted damage to these antiques comes. The far ren are even in the application of the Ver driving biological pests, such as woodworms, killed.

The method according to the invention can also be used for Use rubber articles or other plastics to make them Subsequent impregnation of substrates with suitable plasticizers kidneys to compensate for age-related embrittlement sieren.

Another application of the method according to the invention lies in that seeds are impregnated with appropriate products niert, so for example the shelf life of this seed to improve good.

A particularly preferred application of the invention The procedure is to be seen in the fact that it is in accordance with the invention is possible, pharmaceutical active ingredients in simple and gentle way on a suitable carrier sub deposit strat or in a suitable carrier substrate  bring. By varying the fluid, the temperature, the Pressure, the treatment time and the substrate is then possible, the carrier substrates used here with ent speaking pharmaceutically active ingredients in a given Amount to impregnate.

Especially in the case of combination products strongly differing concentrations of pharmaceutical active substances to be applied, the invention Use procedures particularly effectively. Then here every active ingredient is applied from the specific fluid, the choice of fluids is then chosen so that each Active ingredient only soluble in a special fluid and in the is not or only sparingly soluble in other fluids.

In the food sector, corresponding products, such as for example, cigarettes, cookies, drops or the like, according to the inventions Process according to the invention with appropriate flavorings or flavors are impregnated. This is where this shows method according to the above already described above Share on that it is based on non-toxic fluids, such as in particular Carbon dioxide, because the supercritical fluids after impregnation without residue in the corresponding Gas state can be transferred. This ensures that the products treated in this way are free from solvents.

Furthermore, the method according to the invention can be just if used with soaps, waxes or the like, so perfume or  Apply dyes. This also shows up in particular then the superiority of the method according to the invention compared to the state of the art in cases where such Products such as soaps, cosmetics, lipsticks or the like, which is in direct contact with human skin arrive, absolutely solvent-free with appropriate Impregnating agents, such as perfume or dyes, can be provided.

Likewise, costume jewelry or other souvenir items, which are preferably made of plastics, according to the inventor Process according to the invention with perfume, dyes or other Impregnating agents are impregnated.

The previously described applications of the invention Procedures all have the further decisive advantage that the desired change in properties targeted and only immediately before using the corresponding products can be generated. Here is a further economic advantage of the invention Procedures to see, because a complex inventory of Finished products can be omitted and on the other hand at Fashion articles, the strong taste fluctuations subject to no unsaleable residual items.

Regarding the impregnating agent according to the invention The method to be applied to the substrates should be noted ten that these impregnating agents according to the respective An  application of the method according to the invention and thereby aimed at desired changes in the properties of the substrate judges. Preservatives are particularly successful here Flame retardants, light stabilizers, plasticizers, Water repellents, water repellents, antistatic agents, Anti-pesticides, bactericides, bacteriostatics, perfumes, Dyes, flavors and / or fragrances on the various substrates mentioned above and active pharmaceutical ingredients on appropriate carriers been applied.

A particularly suitable embodiment of the invention The method provides for impregnation of the substrates the pressure of the supercritical fluid with the impregnating agent gradually lowered. This will make the Impregnant in the supercritical fluid like this deteriorates that the impregnating agent ad- or is absorbed. The pressure is preferably reduced to 4 to 20 levels by a value between 5 bar and 20 bar per level. In addition to this pressure drop or instead of that Lowering the pressure is also possible, the temperature to change such that the solubility of the impregnating agent is deteriorated accordingly in the supercritical fluid. This then also leads to a corresponding impregnation of the Substrate with the impregnating agent.

Advantageous further developments of the method according to the invention are specified in the subclaims.

The method according to the invention is described below with the aid of Embodiments explained in more detail.

Embodiment 1 Impregnation of books

A miniature lexicon (Langenscheidts, "Spelling") 40.153 g was pressed into a sleeve in the compressed state given a laboratory autoclave. On the bottom of the autoclave was 1 g tert. Butylated hydroxyanisole (BHA, antioxidant). Carbon dioxide was introduced into the autoclave at 40 ° C. without stirring introduced. The autoclave was at 120-122 ° C at a Carbon dioxide pressure brought from 250-270 bar and there for left like this for an hour. Then was in up to 100 bar 12 steps for a total of 30 minutes expands. The autoclave was then at 100 bar for 4 Minutes brought to normal pressure.

Using blind tests, it was found that the Paper did not contain butylated hydroxyanisole prior to impregnation.

After treatment, the book weighed 40.09 g. H. the original Water adsorbed on paper was due to the treatment dried away. The middle of the book became 24 pages removed, the edges of which were trimmed so that 3 g of paper resulted. This paper was made with ethyl acetate extracted. Thin layer chromatography  was able to find qualitative butylated hydroxyanisole in this extract be directed. The gas chromatographic determination of the Butylhydroxyanisols showed that 2.4% by weight of butylhydroxyanisole in the paper taken from the middle of the book were. The gas released after the treatment Carbon dioxide had no butylated hydroxyanisole.

Embodiment 2 Impregnation of wood

Two pieces of wood of 11.26 g and 11.22 g (diameter 22.5 each mm) were placed in the sleeve of a laboratory autoclave. On the The bottom of the laboratory autoclave was 1 g tert. Butyl hydroxyanisole. Carbon dioxide was added at 40 ° C. without stirring give. The autoclave was at 120-122 ° C with a coal brought dioxide pressure of 250-270 bar. After a dwell The autoclave was raised to 100 bar in 12 hours Steps (13 bar per step, step duration 4 min.) Expan dated. The residual pressure was, as described above, in drained one step.

After the treatment, the pieces of wood now weighed 10.94 g or 10.97 g.

2 layers of 3 mm were machined from the outer layers. The remaining core was then divided into 3 samples, each sample being extracted with ethyl acetate. Thin-layer chromatography was able to qualitatively detect butylated hydroxyanisole in each extract. The quantitative gas chromatographic determination on the extracts gave the following values over the wood cross section:
Inner layer 0.057 mg BHA / cm ³ wood,
Middle layer 0.063 mg BHA / cm ³ wood,
Outer layer 0.124 mg BHA / cm ³ wood.

There was no butylated hydroxyanisole in the wood prior to treatment (BHA) included. This also indicated for the impregnation applied carbon dioxide after expansion in the gaseous No butylated hydroxyanisole.

Embodiment 3 Killing woodworms

A wood infested with woodworms became as in Example 2 treated. After the treatment, microscopic detection was possible that the woodworms had been killed.

Embodiment 4 Impregnating wood with silicone oil

Two pieces of wood (10.33 g, 6.27 g) were made as in Example 2 described, treated, but here instead of Butylhydroxyanisols as impregnating agent silicone oil AK10 (Fa. Wacker) was used. After impregnation, the Pieces of wood have a reduced weight (10.16 g or 6.18 g),  which is attributed to a drainage of the wood. The outer surface of the pieces of wood were removed and the Extracted nucleus with ethyl acetate. In the extract was able to qualitatively detect silicone oil using FT-IR analysis will.

Using blind tests, it was found that the Untreated wood does not contain any silicone oil components exhibited.

Embodiment 5 Impregnation of clay

Pottery shards were, as described in Example 4 above, impregnated with silicone oil AK10 (from Wacker). The shards were which is then rinsed from the outside with ethanol and then extracted with ethyl acetate. In the extract, quanti The silicone oil content was determined. It was 1% by weight.

Embodiment 6 Impregnation of luxury goods

Chewing gum and fruit candies were placed in a laboratory autoclave given. The bottom of the laboratory autoclave was filled with 2 g lemon oil loaded. The autoclave was at 40 ° C with carbon dioxide filled and brought to 50 ° C and 280 bar with stirring. To After a residence time of 1 hour, the pressure was raised to 45 ° C Atmospheric pressure brought.  

Both the chewing gum and the fruit candy smelled intense siv after lemon oil. After external rinsing with ethanol showed both stimulants in addition to their original taste still a clear lemon taste.

Embodiment 7 Impregnation of soap, sugar cubes, Candles, biscuit and pumice sponge

As described in Embodiment 6 above Lump sugar, soap, biscuit impregnated with lemon oil, being however, deviating from embodiment 6, the temperature during the impregnation was 75 ° C.

Furthermore, according to the previously described writing candles and pumice sponge at 50 ° C with lemon oil impregnated.

In both cases the pressure was 280 bar and the treatment time 1 hour.

The sensory test (taste or fragrance) showed that the impregnated substrates clearly tasted of lemon oil or smelled.  

Embodiment 8 Impregnated peeled hazelnuts and tea bags

As described in Embodiment 6 above peeled hazelnuts and tea bags at 95 ° C and pressure of 280 bar impregnated with lemon oil. The treatment time was 1 hour. After cooling to 45 ° C the pressure was on Brought atmospheric pressure.

The treated substrates (tea bags, peeled hazelnuts) were then rinsed with ethanol. It smelled after drying tea in the teabags intensely after lemon oil, while the hazelnuts smelled faintly of lemon oil and tasted good.

Embodiment 9 Impregnation of drug capsules

12 gelatin capsules were filled with gelatin powder fills (filling mass 230-240 mg). In a laboratory autoclave the capsules are placed in a carrier basket. The bottom of the Laboratory autoclaves were loaded with 1 g of vitamin E. The car Klave was at a pressure of 250-270 bar and at a tem temperature of 55-58 ° C with carbon dioxide. To After a treatment time of 45 minutes, the autoclave was  bar increments, each step lasting 3 minutes erte. The filler was removed from the capsules and with Extracted ethanol. By quantitative analysis (UV spectros Copically) 2.5 mg vitamin E could be detected per capsule the.

Embodiment 10 Impregnation of seeds

50 g of grain (wheat, whole grain) were placed in the husk of an Au filled toklaves. The bottom of the autoclave was 1 g Loaded with vitamin E. At a pressure of 260-280 bar and at a temperature between 55 and 58 ° C the sample became a Treated with carbon dioxide for an hour. Then in 5 to 8 bar increments, the expansion time being 4 Minutes per step. The impregnated grain was externally briefly rinsed with ethanol, then crushed and that crushed grain extracted with ethanol at room temperature. In the extract, 3 mg Vitmain E / g grain could be determined by UV spectroscopy be detected.

Sowing experiments showed that the germination ability was in such a way deltered grains had been preserved.  

Embodiment 11 Impregnation of polyvinyl chloride

Polyvinyl chloride powder (Solvic 374 MB, Solvay) was added 0.5 mm thick tablets pressed and in a laboratory autoclave treated with diisononyl phthalate at 120 ° C and 250 bar, where carbon dioxide was used as the fluid. After a treatment time of one hour, the pressure was increased in 12 steps expanded to a pressure of 100 bar. The tablets were rinsed externally with ethanol. At the core of the tablets could qualitative infrared spectroscopic diisononyl phthalate be detected.

Embodiment 12 Impregnation of leather, rubber and Polypropylene

Commercial samples made of leather, rubber and polypropylene were in each case in the laboratory autoclave at 100 ° C and 250 bar Impregnated butylated hydroxyanisole. The fluid became supercritical Carbon dioxide used. After a treatment period of 30 Minutes the pressure was on within 10 minutes Normal pressure expands.  

The treated substrates were externally covered with ethanol rinses. The substrates were then extracted with ethanol. Thin-layer chromatography was able to extract Butylhydroxyanisole can be detected qualitatively.

Claims (16)

1. A method for impregnating substrates, in which the impregnating agent is taken up in a fluid and the substrate is then brought into contact with the fluid for a certain time, since it is characterized by the fact that a supercritical fluid is used as the fluid and that during the contacting and / or thereafter the fluid is brought into the subcritical state. 2. The method according to claim 1, characterized in that one at temperatures between 10 ° C and 300 ° C, preferably between between 32 ° C and 180 ° C, impregnated. 3. The method according to claim 1 or 2, characterized in that at a pressure between 60 bar and 400 bar, preferably between 140 bar and 300 bar, impregnated.   4. The method according to the preceding claims, characterized characterized in that the supercritical fluid is alkanes, especially ethane, propane or pentane, ammonia, fluorine Chlorine alkanes, carbon dioxide and / or carbon monoxide used alone or in a mixture. 5. The method according to the preceding claims, characterized characterized in that the supercritical fluid at least adds a moderator. 6. The method according to claim 5, characterized in that the Moderator in the supercritical fluid in a concentration between about 1% by volume and about 10% by volume, preferably between about 2% by volume and about 5% by volume is present. 7. The method according to any one of the preceding claims, characterized characterized in that a natural Select substrate. 8. The method according to claim 7, characterized in that one a substrate made of ceramic, leather, paper or Selects wood. 9. The method according to claim 7 or 8, characterized in that the substrate is books or antiques. 10. The method according to claim 7, characterized in that the Substrate grains, plant seeds or seeds.   11. The method according to any one of claims 1-6, characterized records that as a substrate food or luxury food selects. 12. The method according to any one of claims 1-6, characterized records that as a substrate drug or Drug carriers. 13. The method according to claim 12, characterized in that that one acts as an impregnating agent or pharmaceutical additives. 14. The method according to any one of claims 1-6, characterized characterized in that rubber, plastics, Waxes or soaps. 15. The method according to any one of the preceding claims, characterized characterized in that as a waterproofing agent preserve agents, light stabilizers, plasticizers, hydrophobicity agents, hydrophilizing agents, antistatic agents, anti Pesticides, bactericides, bacteriostatics, perfumes, Selects flavors, fragrances and / or colors. 16. The method according to any one of the preceding claims, characterized characterized in that the pressure after the pre given time gradually lowered.