DE102008037898A1 - Method and device for sterilizing packaging and / or filter material and / or containers, use of plasma in this regard and appropriately treated material or container - Google Patents

Abstract

The invention relates to a method and a device for disinfecting or sterilizing packaging material and / or containers and / or filter material, wherein the material or the container is treated with a gas generated in a plasma reactor. The plasma treatment achieves a significantly improved sterilization of corresponding materials, in particular packaging materials and / or containers for packaging and / or storage of foods, beverages and other hygienically sensitive substances. Finally, the use of plasma to treat such materials or containers as well as appropriately treated materials or containers is suggested.

Description

The The invention relates to a method and a device for disinfection or sterilization of packaging material and / or containers and / or filter material, in particular for food, Drinks, cosmetics, medical devices and others Products with increased hygienic requirements, in particular also for air filters for germ-free filling and / or packaging equipment. Furthermore, the invention relates to Use of plasma for the treatment of such materials or Containers. Finally, the invention relates appropriately treated materials or treated accordingly Container.

Out In the industrial field are a variety of solid, liquid or pasty products known before use or for further transport into containers, such as bottles, Glasses or packaging to be filled or filled have to. To make the bottled products then more durable Different methods are used, of which the best known the heat treatment (boiling, autoclaving) is. there become germs contained in the product or packaging material, inactivated, leaving a later questionable bacterial contamination (Spoiling) of the product suppressed or completely prevented becomes.

It But there are a lot of products that you do not treat thermally can or wants, as this z. B. taste changes arise, valuable ingredients are impaired (eg, vitamins) or the product is adversely affected altogether (eg caramelizing, melting). Furthermore, the thermal Treatment increased demands on the container, the closure or the packaging and is also very costly overall, since high amounts of energy have to be spent and themselves Moreover, this process is very tedious.

Even though in the industrial processing and packaging of products usually highest hygienic care is applied comes it always comes back to microbiological contamination during the packaging or filling process. these can but not immediately after, but first after a long time (days, weeks) when the product already at the end user. This can be disadvantageous taste sensations or even serious at worst health problems occur.

Of the critical moment leading to microbiological contamination may take place when the product is bottling or Packaging with the material of the container or packaging comes into contact and the material is already undesirable Carries germs, the z. B. via the airway or through other contacts may have reached it.

In In this context, it is known to and / or packaging steps in virtually germ-free environment (so-called Aseptic Filling). The atmosphere in such germ-free filling / packaging systems is thereby High-performance filter, namely so-called high efficiency Particulate Airfilter (HEPA filter) provided. Such filters have such a small pore diameter that even viruses can be held back. however These filters also tend to germinate, so ultimately the sterility during the filling / packaging step can not be guaranteed.

Of the The present invention is therefore based on the object, a fast and gentle sterilization of packaging material and / or containers to be realized shortly before the filling or packaging process and to provide effective sterilization of filter material.

These Task is with respect to a method of disinfection or sterilization packaging material and / or containers and / or filter material, in particular of such plastic packaging materials, solved with the features of claim 1. After that is the material or the container with a in one Plasma reactor produced gas treated.

With the features of claim 22 is an inventive Device for disinfecting or sterilizing such materials or containers indicated.

Of Further are corresponding to the claims 24 and 25 treated packaging or filter materials or containers or the use of plasma for the treatment of such materials or Containers proposed.

advantageous Embodiments of the invention are the respective subsequent claims removable.

According to the invention It has been recognized that by treating with a plasma the hygienic properties packaging and container materials or filter materials, but especially of closure elements, in particular of plastic, can be significantly improved.

plasma is a partially or fully ionized gas, that to a considerable extent free charge carriers such as Ions, but especially free electrons. It can plasma from the ambient air or other suitable pure gases or Gas mixtures are generated.

The use of plasma has hitherto only been known from other technical fields. So will in US 6,467,467 B1 the use of plasma for the reduction of gaseous and / or solid impurities in the exhaust stream of internal combustion engines proposed.

in the Under the present invention, it has been recognized that the surface of packaging materials by contact with plasma or the modified gases produced in the plasma in a particularly advantageous manner becomes. Treated materials are sterilized in a few seconds, d. H. disinfected. The temperature only rises by a few degrees C, which does not affect the treated materials.

In According to the invention, the disinfection of the Surfaces of the packaging materials only a small Energy input required.

It is believed that the plasma partially breaks down the air molecules into atomic fragments and thereby generates so-called "reactive oxidizing species" (ROS), eg from air OH radicals In addition, the generation of plasma in the presence of oxygen is generally associated with the production of ozone (O ₃ ).

The Plasma causes an exchange of electrons on the surface the treated materials, resulting in a hydrophilization of the Surface leads and thus the "clumping" reduced by microorganisms.

The inventive method is not only suitable for disinfection or sterilization of packaging material, but can also be successfully used to treat filter material use to eliminate microbial contamination. Thus, the inventive Method especially in connection with filling and / or Packaging plants for the periodic treatment used there HEPA filters are used. However, there are also all other possible Filter materials treatable.

In A preferred embodiment of the method is the product and / or the product surface with a plasma, in particular with a non-thermal atmospheric plasma, in Brought in touch. An atmospheric plasma is obtained at ambient pressure from the surrounding air. At a non-thermal plasma, the electrons have a higher Temperature than the heavy particles. So can the temperature of the gas be settled in the range of ambient temperature, while individual electrons have very high energy contents. While the generation of an atmospheric, non-thermal Plasma is preferred, alternatively, the application of a low pressure or high-pressure plasma conceivable. Furthermore, the used Plasma also in complete or local thermal equilibrium are located. Alternatively, the product can not be used directly with the plasma, but much more in contact with the gas produced in the plasma become.

With The process of the invention will be particularly Good results are obtained when the plasma treated gas after the passage over the surface to be disinfected recycled, d. H. is fed again into the plasma zone.

An embodiment of the method is preferred in which the generated gas has ozone (O ₃ ) and / or OH radicals and / or further oxidants (reactive oxidizing species, ROS). Due to the presence of such strongly reactive constituents, on the one hand microorganisms are destroyed and on the other hand the surface of the material to be treated is conditioned in an advantageous manner as described above.

A further increase in efficiency results when looking at the plasma reactor supplies additional oxygen. As the nitrogen the air (about 78%) does not participate in the plasma reaction can This significantly increases the concentration of ROS.

In a further advantageous embodiment of the invention Process is the gas generation in terms of a high content optimized for OH radicals. In the context of the present invention could be found that an increased content of such Hydroxyl radicals in the gas stream in a surprising manner leads to a greatly improved sterilization. The OH radicals therefore have particularly effective antimicrobial properties on.

With regard to an increased content of OH radicals, it is preferred that water is supplied to the plasma reactor, in particular in the form of atmospheric moisture and / or water vapor. Thus, an increased yield of OH radicals can be achieved during the plasma generation, namely on the one hand from the water itself according to the reaction H ₂ O → OH + H, and on the other hand with further reaction of the molecular hydrogen with the ozone formed during plasma generation, namely the reaction H + O ₃ → OH + O ₂ .

A further preferred embodiment of the method is characterized in that in a first step, ozone generated in the plasma reactor is converted into OH radicals by subsequent application of UV radiation and subsequent contact with water. Thus, it has been found that ozone can be converted into electronically excited atomic oxygen by means of exposure to UV radiation, namely according to O ₃ .O ₂ + O (FIG. ¹ D). This electronically excited atomic oxygen O ( ¹ D) can be converted by the further reaction with existing water into OH radicals, namely according to O ( ¹ D) + H ₂ O → 2 OH.

With regard to a particularly effective formation of the electronically excited atomic oxygen O ( ¹ D), accompanied by the highest possible yield of OH radicals, it is proposed that the UV radiation used has a wavelength of about 240 nm up to about 300 nm, in particular about 270 nm. In the stated wavelength range, a particularly high yield of OH radicals could be obtained in a surprising manner.

In In a particularly preferred embodiment, the plasma is preferably a non-thermal atmospheric plasma, by a dielectrically impeded discharge (barrier discharge) won. Despite the prevailing ambient pressure, a plasma can be used produced far from thermal equilibrium is. This makes it possible to provide particularly high-energy electrons. Although the implementation of a dielectrically handicapped Discharge is preferred, the plasma can also by other species be generated, for example by laser radiation, by DC voltage (Sparkover), by microwave radiation, magnetic Suggestion or the like.

In addition, it is proposed that barriers are used which are coated with photoactive titanium dioxide, the barriers optionally having ceramic material. Ceramic materials initially provide particularly effective dielectrics. The barrier can now be coated with photoactive titanium dioxide. This titanium dioxide is characterized by an energy absorption during the discharge, wherein the absorbed energy is then released again, inter alia, as ultraviolet radiation. Accordingly, the UV radiation thus emitted can make a valuable contribution to the formation of electronically excited atomic oxygen O ( ¹ D) as described above.

in the With regard to plasma generation by means of electrical discharge a development of the method preferred in which the electrical Voltage of about 15 kV to about 40 kV and / or the Plasma frequency of about 5 kHz to about 50 kHz. With These parameters have been achieved particularly good results.

In a further advantageous embodiment of the inventive concept The plasma is pulsed generated, with a clock of about 0.1 sec until about 3 sec, in particular about 2 sec, is used. With these Parameters have been achieved good results.

The Treatment of the materials is advantageously carried out in such a way that the material and / or the material surface or the container and / or the container inner surface and / or the container surface with the plasma, in particular a non-thermal atmospheric plasma, is brought into contact. In the sense of a gentle treatment, especially taking into account a maximum limit of heat input, However, it may also be sufficient, the materials to be treated with the reactive gas generated in plasma in contact bring to. In this case, the generated reactive gas can be treated Materials are supplied. The materials can do this occupy a certain distance from the plasma or the discharge zone.

Preferably is the treatment of the product in a reactor and / or in or performed behind a discharge zone. Especially Preferably, a discharge zone is located in an in suitably encapsulated reactor. The product to be treated is then brought into contact with the reactive gas generated in the plasma. For a continuous operation is further one Provide bypass for the product flow through the reactor.

When particularly advantageous for the invention Procedure has a treatment duration of about 20 sec to about 120 sec, in particular about 60 sec to about 120 sec, and in particular about 90 sec exposed. The mentioned treatment times ask doing an optimal compromise between treatment success (germ killing) and economy. The material to be treated can optionally during the treatment also constantly in motion be kept (in-line treatment).

Provided the material to be treated is not in direct contact with the plasma should come or may, has a distance to be treated Material from the plasma or from the discharge zone of about 5 cm to about 20 cm, especially from about 11 cm to about 17 cm, as a special proved effective.

With the process of the invention can be materials or plastic containers particularly good antimicrobial to treat. Such materials generally do not tolerate strong ones Temperature increase, allowing a thermal treatment usually feasible only with an ultimately insufficient heating is.

Therefore These materials are predestined for the application the method according to the invention.

So can be materials or containers for packaging and / or Storage of food, drinks and other hygienic sensitive substances with the inventive Easy, gentle and quick sterilization process.

Especially Good results are in the treatment of beverage bottles and in particular the associated closure elements (screw cap) made of plastic. For the treatable beverage bottles It can be both disposable and reusable. Although the screw caps used always brand new on the beverage bottles be applied, a previous sterilization is necessary, in particular when bottling lemonade, juices or the like Soft drinks.

alternative or in addition can be with the inventive Process also any filter materials, but especially HEPA filters (High Efficiency Particulate Air Filter) treat which for air purification for germ-free filling and / or Packaging plants are used.

A preferred device for disinfecting or sterilizing packaging material and / or containers and / or filter material finally shows an input and / or rejection device for the treatment to be treated Material and / or container on. This is a continuous and rapid treatment of the materials.

It Now there are different ways of teaching the present Invention in an advantageous manner and further develop. On the one hand, on the subordinate claims, on the other hand, the following explanation of experimental examples to refer. The following examples are for closer Explanation of the subject invention, but without him to limit to this.

test Examples

Experimental Example 1

to Determination of the effectiveness of plasma-generated oxidizing Species (ROS), especially ozone and OH radicals, has become a variety of test dishes with a methylene blue solution produced Exposed to gas. Methylene blue is a phenothiazine derivative and a known redox indicator. An oxidizing effect of the produced Gas leads to a decolorization of the initial deep blue solution.

• – Abstand vom Plasma (6 cm, 11 cm und 17 cm),
• – Behandlungsdauer (60 sec, 90 sec und 120 sec),
• – Feed für den Plasmareaktor (Luft oder reiner Sauerstoff, ggf. mit Wasserbeimischung), und
• – zusätzlicher Einsatz von UV-Strahlung.

The following parameters have been varied:

• Distance from the plasma (6 cm, 11 cm and 17 cm),
• Duration of treatment (60 sec, 90 sec and 120 sec),
• - Feed for the plasma reactor (air or pure oxygen, possibly with added water), and
• - additional use of UV radiation.

The Experimental dishes were under variation of the above parameters treated with the gas generated in the plasma. The success of the treatment was determined by the achieved decolorization of each sample assessed.

While with the sole use of atmospheric air at all three intervals and a treatment duration of 120 sec only a slight discoloration can be detected could supplied the supply of the plasma reactor with pure Oxygen at distances of 6 cm and 11 cm already to one clear decolorization, taking here with a treatment period of 60 sec the worst result was achieved.

Has been the feed stream of pure oxygen additionally water admixed, could also at a distance of 17 cm and a Treatment period of 90 sec already a significant discoloration be determined. This discoloration was at the same distance and the same treatment time without the addition of water significantly less pronounced.

at a treatment time of 120 sec and the use of oxygen with the addition of water is at a distance of 17 cm one almost complete decolorization succeeded.

The By far the best results are with pure oxygen as a feed with the addition of water and the additional use succeeded by UV radiation with a wavelength of 270 nm. Here could at a distance of 11 cm and a treatment duration of 90 sec as well as at a distance of 17 cm and a treatment time 120 sec complete discoloration of the sample be achieved. At a distance of 6 cm and a treatment period After 60 seconds, the sample was significantly brightened, but not yet completely decolourised.

Experimental Example 2:

It were a variety of samples consisting of screw caps for plastic beverage bottles (polystyrene), artificially contaminated with various germs and spores and then subjected to treatment in plasma. In this case, the germs within 5 sec by 5 log levels (ie. H. 99.999%).

Experimental Example 3:

The inactivation rate achieved by the method according to the invention has been determined on the basis of two different microorganisms. On the one hand, contaminated samples have been prepared and treated with Aspergillus niger (black mold) and on the other hand with Bacillus atrophaeus (formerly Bacillus subtilis, hay bacillus, a widely distributed gram-positive, rod-shaped and flagellated bacterium which is an aerobic-growing endosporogen). The achieved reduction in the number of bacteria (CFU = colony-forming units) can be deduced together with the respective treatment time from the following table: of germ Treatment time [sec] Germ count [CFU] Plasma treatment BEFORE AFTER Reduction [log] Aspergillus niger 60 60 30 540,000 <2 94,000 <1 1,800 <2 5.7>5> 2.9 Bacillus atrophaeus (formerly Bacillus subtilis) 30 10 280,000 <3 50,000 <2 5.1> 4.6

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - US 6467467 B1 [0014]

Claims (25)

Method for disinfection or sterilization packaging material and / or containers and / or filter material, wherein the material or the container with a in one Plasma reactor produced gas is treated. Method according to claim 1, characterized in that that the gas generated in a plasma reactor has plasma. Method according to claim 1 or 2, characterized that the gas generated in a plasma reactor is a non-thermal having atmospheric plasma. A method according to claim 2 or 3, characterized in that the gas generated in a plasma reactor ozone (O ₃ ) and / or OH radicals and / or further oxidants ("Reactive Oxidizing Species" (ROS)) has. Method according to one of claims 1 to 4, characterized in that the plasma reactor supplied oxygen becomes. Method according to one of claims 1 to 5, characterized in that the gas generation in terms of a high content of OH radicals is optimized. Method according to one of claims 1 to 6, characterized in that the plasma reactor water, in particular in the form of humidity and / or water vapor supplied becomes. Method according to one of claims 1 to 7, characterized in that in a first step in the plasma reactor generated ozone by subsequent exposure to UV radiation and subsequent contact with water into OH radicals becomes. Method according to claim 8, characterized in that that the UV radiation used has a wavelength of approx. 240 nm to about 300 nm, in particular about 270 nm. Method according to one of claims 1 to 9, characterized in that the plasma by a dielectrically disabled discharge (barrier discharge) is generated. Method according to claim 10, characterized in that that barriers are used which react with photoactive titanium dioxide coated, the barriers optionally ceramic material exhibit. Method according to claim 10 or 11, characterized that the electrical voltage is from about 15 kV to about 40 kV and / or the plasma frequency is from about 5 kHz to about 50 kHz. Method according to one of claims 1 to 12, characterized in that the plasma is generated pulsed, wherein a clock of about 0.1 sec to about 3 sec, in particular about 2 sec, is used. Method according to one of claims 1 to 13, characterized in that the material and / or the material surface or the container and / or the container inner surface and / or the container surface with a plasma, especially with a non-thermal atmospheric Plasma, is brought into contact. Method according to one of claims 1 to 14, characterized. that treatment in a reactor and / or performed in or behind a discharge zone becomes. Method according to one of claims 1 to 15, characterized by a treatment time of about 20 sec about 120 seconds, especially about 60 seconds to about 120 seconds, and in particular about 90 sec. Method according to one of claims 1 to 16, characterized in that the distance of the treated Material from the plasma or from a discharge zone about 5 cm to about 20 cm, in particular about 11 cm to about 17 cm. Method according to one of claims 1 to 17, characterized in that to be disinfected Material or the container made of plastic. Method according to one of claims 1 to 18, characterized in that the material or the container for packaging and / or storage of food, beverages and other hygienically sensitive substances. Method according to claim 19, characterized that the material or the container beverage bottles, in particular of plastic, and / or closure elements, in particular made of plastic, for the same bottles. Method according to one of claims 1 to 20, characterized in that the material filter, in particular HEPA (High Efficiency Particulate Air Filter) filter which for air purification for germ-free filling and / or Packaging plants are used. Device for disinfection or sterilization packaging material and / or containers and / or filter material, characterized by a plasma reactor. Apparatus according to claim 22, characterized by an input and / or ejection device for the treated Material and / or container. Packaging material or container or Filter material, characterized in that the packaging material or the container or the filter material of a treatment has been subjected to plasma, and in particular to a method has been treated according to one of claims 1 to 21. Use of plasma for the treatment of packaging material and / or containers, in particular packaging material or containers of plastic, and in particular of packaging material or containers used for packaging and / or storage of Food, beverages and other hygienically sensitive Substances are provided, and / or for the treatment of filter material, especially HEPA filters.